FAQ

Batteries


General: Does the battery have to be disconnected from the vehicle when it is being charged with a CTEK charger?
No, CTEK chargers cannot damage sensitive electronics. So, you don't have to disconnect the battery from the vehicle! However, you should take extra care when using Recond because the voltage is 15.8V. Most manufacturers consider everything to be fine as long is voltage is below 16V and CTEK is under that limit by a good margin, even during Recond. Note that the service life of some components is shortened by high voltage. A rule of thumb says that a light bulb's life span is halved by increasing voltage by 5%, but this is normally not any great danger. If you have any sensitive electronics for which the manufacturer warns against high voltage: disconnect them!; What happens if I use the charger for batteries that are larger than you recommend?
Using a small charger makes the charging time longer. Sometimes, this is critical. In such cases, you should use a larger charger. If you only use the charger for maintenance charging, a really small charger is often sufficient.; Can I maintenance charge several batteries at the same time?
CTEK chargers are fully capable of charging or maintenance charging several batteries connected in parallel provided that the total size of the batteries (Ah) does not exceed the recommended size for the charger. Remember to completely charge each battery individually before connecting them. Otherwise, there is a risk of current surges between that batteries that can cause unnecessary wear.; Are there CTEK chargers for other battery types?
CTEK has decided to make the world's smartest battery chargers for lead/acid batteries. And we're satisfied with that for now. We do not currently offer chargers for other battery types.; Can a frozen battery be charged?
No, the battery must be thawed first. Note that the battery was discharged first. Otherwise, it would not have frozen. Check the battery carefully for cracks or other damage. A fully-charged battery freezes at -67 degrees Celsius, while a drained battery can freeze at just a few degrees below zero. If you think your battery is or was frozen, we recommend that you have the battery tested. It has probably been damaged and may have to be replaced.; Can I connect all of my 12V batteries and maintenance charge them all at the same time?
That is possible. But remember that all batteries should be fully charged individually before they are connected in parallel. Bear in mind that the combined size of the batteries must not exceed the recommended charging range of the charger. If the batteries differ greatly in size (Ah), age and condition, this could cause great wear to the batteries that are in the best condition. A battery in good condition that is being stored for the winter might self-discharge under 90% of fully charged once or twice over the course of the winter. But, batteries in poor condition may do this once or twice a week. If the batteries are parallel connected with a charger connected, each individual battery does not get the charge it needs. It may be easier to set a Comfort Indicator on all individual batteries and move a charger between the batteries needing charging. This gives each battery the best charging based on its individual needs and no battery will become worn and require early replacement.; How much electrical energy does it take to charge a lead-acid battery with a CTEK charger?
Here is an easy way to calculate the electrical energy expenditure when charging a lead-acid battery with CTEK chargers.

Given:
Battery voltage, Bv = 12V
Battery size, Bs = 75Ah
The battery's charge level, Bl = 50%
The battery's efficiency level = 87%
CTEK charger's efficiency level = 80%

Calculate:
Energy consumed from the mains supply to fully charge the battery (En)

First, how much energy is needed to fill the battery?
12V x 75Ah x 50% = 12x75x0.5=450Wh

How much energy does the charger need to deliver based on the battery's efficiency level?
450Wh / 87% = 450/0.87 = 517Wh

How much energy does the mains supply deliver to the charger when taking the efficiency level into consideration?
En = 517Wh / 80% =517 / 0.8 = 647Wh or 0,647kWh.

Answer:
0.647kWh is used to charge the battery based on the given data.
With today's electricity prices, the cost is about SEK 1 to charge a halv-charged 75Ah battery.

It is possible to calculate to 80% efficiency for all models of CTEK chargers.
Vary the battery sizes (Bs) and charging level (Bl) to calculate other examples.


Battery type: Can I charge lithium ion batteries with my CTEK charger?
Our chargers have a charging curve suited to lead-acid batteries. We have heard reports from around the world that our chargers are also used for Li-Ion batteries, but this is outside our charger recommendations. If you study Li-Ion manuals, it is amazing how well several of our chargers match 4x Li-Ion batteries. However, we cannot guarantee that everything is perfect and you assume all risk and liability if you use the charger with these types of batteries. Lithium is an extremely reactive material and battery manufacturers put great efforts into controlling and monitoring the batteries. Consider CTEK chargers as a smart power source that CTEK will not guarantee for any batteries other than lead-acid batteries.; What do the abbreviations MF, GEL and AGM mean?
Gel, AGM, Vlies, MF, Calcium/Calcium and Hybrid are abbreviations for different types of lead-acid batteries. Thus, they can be charged with CTEK chargers. Read more about what the different abbreviations stand for and how they are different in the battery school.; I have an AGM battery. Do I charge it in snowflake mode?
It depends. Optima and Hawker recommend snowflake mode. If there is no indication on the battery, use car mode for batteries over 14Ah or MC mode for batteries under 14Ah.; Can I charge GEL batteries with my CTEK charger?
GEL batteries are a type of lead/acid battery where the acid is bound in a gel. These batteries can be charged with a CTEK charger with no problems whatsoever.; Are there CTEK chargers for other battery types?
CTEK has decided to make the world's smartest battery chargers for lead/acid batteries. And we're satisfied with that for now. We do not currently offer chargers for other battery types.


Charger settings: I have an AGM battery. Do I charge it in snowflake mode?
It depends. Optima and Hawker recommend snowflake mode. If there is no indication on the battery, use car mode for batteries over 14Ah or MC mode for batteries under 14Ah.


Installation: Can I maintenance charge several batteries at the same time?
CTEK chargers are fully capable of charging or maintenance charging several batteries connected in parallel provided that the total size of the batteries (Ah) does not exceed the recommended size for the charger. Remember to completely charge each battery individually before connecting them. Otherwise, there is a risk of current surges between that batteries that can cause unnecessary wear.; Can I connect all of my 12V batteries and maintenance charge them all at the same time?
That is possible. But remember that all batteries should be fully charged individually before they are connected in parallel. Bear in mind that the combined size of the batteries must not exceed the recommended charging range of the charger. If the batteries differ greatly in size (Ah), age and condition, this could cause great wear to the batteries that are in the best condition. A battery in good condition that is being stored for the winter might self-discharge under 90% of fully charged once or twice over the course of the winter. But, batteries in poor condition may do this once or twice a week. If the batteries are parallel connected with a charger connected, each individual battery does not get the charge it needs. It may be easier to set a Comfort Indicator on all individual batteries and move a charger between the batteries needing charging. This gives each battery the best charging based on its individual needs and no battery will become worn and require early replacement.


Series & parallel connection: Can I maintenance charge several batteries at the same time?
CTEK chargers are fully capable of charging or maintenance charging several batteries connected in parallel provided that the total size of the batteries (Ah) does not exceed the recommended size for the charger. Remember to completely charge each battery individually before connecting them. Otherwise, there is a risk of current surges between that batteries that can cause unnecessary wear.; Can I connect all of my 12V batteries and maintenance charge them all at the same time?
That is possible. But remember that all batteries should be fully charged individually before they are connected in parallel. Bear in mind that the combined size of the batteries must not exceed the recommended charging range of the charger. If the batteries differ greatly in size (Ah), age and condition, this could cause great wear to the batteries that are in the best condition. A battery in good condition that is being stored for the winter might self-discharge under 90% of fully charged once or twice over the course of the winter. But, batteries in poor condition may do this once or twice a week. If the batteries are parallel connected with a charger connected, each individual battery does not get the charge it needs. It may be easier to set a Comfort Indicator on all individual batteries and move a charger between the batteries needing charging. This gives each battery the best charging based on its individual needs and no battery will become worn and require early replacement.; Can I charge a 24V system with two 12V chargers connected in series?
Yes, this is perfectly OK and is actually preferable for the batteries. Connect one charger for each battery.; I'm thinking about installing an electric motor in my sailboat. The motor is run on 48V and I was thinking about either running on eight 6V batteries (deep cycle batteries) or four 12V batteries (type AGM).
Yes, you can use two 24V chargers in your 48V system, but you would get the best results from using four 12V chargers instead. This gives you better control so all batteries obtain the same degree of charge. For two serial-connected batteries, a 24V charger has no control over the voltage being equally distributed over the two batteries. On a wet battery, it is normal for there to be some gassing so that the battery can become fully charged. But, CTEK chargers do not overload the batteries, which prevents major gassing from occurring. If it is not possible to ventilate away the oxy-hydrogen gas, we recommend against using such batteries. Some “wet” batteries have a hose nipple that you can use to connect a hose for venting away the oxy-hydrogen gas. Even though oxy-hydrogen gas is not a problem during normal charging, problems can arise with the battery, e.g. cell fault. In such cases, gassing can be huge if the accident occurs before the charger switches off.


Choosing a charger: Can I charge lithium ion batteries with my CTEK charger?
Our chargers have a charging curve suited to lead-acid batteries. We have heard reports from around the world that our chargers are also used for Li-Ion batteries, but this is outside our charger recommendations. If you study Li-Ion manuals, it is amazing how well several of our chargers match 4x Li-Ion batteries. However, we cannot guarantee that everything is perfect and you assume all risk and liability if you use the charger with these types of batteries. Lithium is an extremely reactive material and battery manufacturers put great efforts into controlling and monitoring the batteries. Consider CTEK chargers as a smart power source that CTEK will not guarantee for any batteries other than lead-acid batteries.; Can I charge GEL batteries with my CTEK charger?
GEL batteries are a type of lead/acid battery where the acid is bound in a gel. These batteries can be charged a CTEK charger with no problems whatsoever.; What happens if I use the charger for batteries that are larger than you recommend?
Using a small charger makes the charging time longer. Sometimes, this is critical. In such cases, you should use a larger charger. If you only use the charger for maintenance charging, a really small charger is often sufficient.; Are there CTEK chargers for other battery types?
CTEK has decided to make the world's smartest battery chargers for lead/acid batteries. And we're satisfied with that for now. We do not currently offer chargers for other battery types. Read more at Charging school – battery types.

Marine


General: Are the primary and secondary sides galvanically separated in your chargers?
Yes, all CTEK chargers are galvanically separated.


Installation: I'm thinking about installing an electric motor in my sailboat. The motor is run on 48V and I was thinking about either running on eight 6V batteries (deep cycle batteries) or four 12V batteries (type AGM).
Yes, you can use two 24V chargers in your 48V system, but you would get the best results from using four 12V chargers instead. This gives you better control so all batteries obtain the same degree of charge. For two serial-connected batteries, a 24V charger has no control over the voltage being equally distributed over the two batteries. On a wet battery, it is normal for there to be some gassing so that the battery can become fully charged. But, CTEK chargers do not overload the batteries, which prevents major gassing from occurring. If it is not possible to ventilate away the oxy-hydrogen gas, we recommend against using such batteries. Some “wet” batteries have a hose nipple that you can use to connect a hose for venting away the oxy-hydrogen gas. Even though oxy-hydrogen gas is not a problem during normal charging, problems can arise with the battery, e.g. cell fault. In such cases, gassing can be huge if the accident occurs before the charger switches off.; I have a 10-metre motorboat with two engines. I have two 115Ah starter batteries and a consumer bank of four batteries of 115Ah each. What would be your charging recommendation for my boat?
I have two possible solutions for you, depending on your charging needs. Charging during travel: In order to be out on the water for a long time with the consumer bank being discharged, you can connect a DC/DC charger, D250S DUAL, on the cable between the generator and the starter battery. This lets you charge the consumer bank up to 20A when the generator is running. You can also connect another current source, such as a solar panel. D250S DUAL has CTEK's different charging stages and temperature compensation that ensures that voltage is correct regardless of the temperature around the battery. If you want more powerful charging, you can add a SMARTPASS. This increases charging to up to 60A. Charging via land current: When you have access to 220 sockets, I recommend one charger for the starter bank and one for the consumer bank. Choose the size based on the discharged batteries themselves and how quickly you want them recharged. I would recommend an M100 for the starter batteries and an M300 for the consumer bank.

Installation


General: Can CTEK chargers be used for caravans and boats?
Yes, all CTEK chargers can be permanently connected. It is often a good idea to choose a slightly larger charger considering how often consumers (e.g. lamps and refrigerators) are connected. Some charger models have ring terminals for quick mounting, e.g. M200 and M300. The chargers with a quick connector always have access to both ring terminals and battery clamps.; Does the battery have to be disconnected from the vehicle when it is being charged with a CTEK charger?
No, CTEK chargers cannot damage sensitive electronics. So, you don't have to disconnect the battery from the vehicle! However, you should take extra care when using Recond because the voltage is 15.8V. Most manufacturers consider everything to be fine as long is voltage is below 16V and CTEK is under that limit by a good margin, even during Recond. Note that the service life of some components is shortened by high voltage. A rule of thumb says that a light bulb's service life is halved by increasing voltage by 5%, but this is normally not any great danger. If you have any sensitive electronics for which the manufacturer warns against high voltage: disconnect them!; Why do you connect minus to ground and not to the battery?
You can connect a CTEK charger directly to the minus pole instead of to the chassis without any risk. CTEK recommends connecting the minus clamp to ground instead of the minus pole to eliminate the risk of sparking close to the battery. Explosive oxy-hydrogen gas could be found near the battery. However, CTEK chargers are non-sparking and with their smart charging, generate minimal oxy-hydrogen gas. There is therefore very little risk associated with connecting both clamps to the battery poles.


Car: I want to permanently install a CTEK in my car to charge the car battery when the car's engine/passenger compartment heater is connected to the mains. How do I do this?
We don't have any description for this, but the installation is not so complicated. The charger must not be installed inside the engine compartment. In such cases, the main cable (230V) must be of an engine heater type as per Nordic regulations. The charger should instead be installed in the passenger compartment. Connect the mains cable to the passenger compartment heater socket, with a branching if so desired. Connect the battery cable to the car battery, preferably with the ring terminals supplied with the charger. If the battery is mounted in the engine compartment in the car, you can route the battery cable through the car bulkhead (the wall between the passenger compartment and the engine compartment). You should install a fuse on the plus battery cable (red), as close to the battery as possible since it is a permanent installation.


Boat: Can CTEK chargers be used for caravans and boats?
Yes. All CTEK chargers can be permanently connected. It is often a good idea to choose a slightly larger charger considering how often consumers (e.g. lamps and refrigerators) are connected. Some charger models have ring terminals for quick mounting, e.g. M200 and M300. The chargers with a quick connector always have access to both ring terminals and battery clamps.


Caravan/Camper: Can CTEK chargers be used for caravans and boats?
Yes. All CTEK chargers can be permanently connected. It is often a good idea to choose a slightly larger charger considering how often consumers (e.g. lamps and refrigerators) are connected. Some charger models have ring terminals for quick mounting, e.g. M200 and M300. The chargers with a quick connector always have access to both ring terminals and battery clamps.


Series connection: Can I charge a 24V system with two 12V chargers connected in series?
Yes, this is perfectly OK and is actually preferable for the batteries. Connect one charger for each battery.; I'm thinking about installing an electric motor in my sailboat. The motor is run on 48V and I was thinking about either running on eight 6V batteries (deep cycle batteries) or four 12V batteries (type AGM).
Yes, you can use two 24V chargers in your 48V system, but you would get the best results from using four 12V chargers instead. This gives you better control so all batteries obtain the same degree of charge. For two serial-connected batteries, a 24V charger has no control over the voltage being equally distributed over the two batteries. On a wet battery, it is normal for there to be some gassing so that the battery can become fully charged. But, CTEK chargers do not overload the batteries, which prevents major gassing from occurring. If it is not possible to ventilate away the oxy-hydrogen gas, we recommend against using such batteries. Some “wet” batteries have a hose nipple that you can use to connect a hose for venting away the oxy-hydrogen gas. Even though oxy-hydrogen gas is not a problem during normal charging, problems can arise with the battery, e.g. cell fault. In such cases, gassing can be huge if the accident occurs before the charger switches off.

Accessories


General: I have a COMFORT INDICATOR connected to the battery in my car. The red lamp flashes even after I've fully charged the battery with my MULTI XS 3600/ MXS 3.6/Zafir 45/M45. Should it do this? I thought the COMFORT INDICATOR would be green when the battery is fully charged?
The CTEK COMFORT INDICATOR is exactly what the name says – an indicator. It provides a snapshot of the system voltage level and works best when the battery has reached a rest level (this can take up to a few hours after the battery was used). As soon as you open a car door or turn on the ignition, the COMFORT INDICATOR will show the actual status, which means that the voltage level will be temporarily indicated as yellow or even red. This is nothing to worry about. The COMFORT INDICATOR is working correctly. To make things easier, you can position the COMFORT INDICATOR where you can see it without having to unlock or use any voltage in the car.; I have a COMFORT INDICATOR connected to the battery all the time. Is there any risk of the battery discharging?
No, the purpose of the indicator is to allow you to quickly and easily see whether the battery must be charged, thereby reducing the risk of the battery being damaged because of being discharged. The COMFORT INDICATOR uses about 1.5mA. This would cause the battery to discharge only a few minutes faster than without the indicator.; How do I interpret the colour markings on my COMFORT INDICATOR?
GREEN: battery voltage is over 12.65 = battery is fully charged and does not require charging YELLOW: battery voltage is between 12.65 and 12.4V = battery is well charged. Recharge if you have time and opportunity RED: battery voltage is below 12.4V = time for charging to prevent battery damage; Can I use your COMFORT CONNECT CIG PLUG to charge the battery through the cigarette socket in my car?
Yes, but you should check that you have voltage to the socket even if the vehicle is switched off. If, for example, you can charge a mobile phone or get a GPS to work when the car ignition is switched off, you can also charge the car battery this way.; Does CTEK have a Y-cable so you can charge 2 MCs with one charger? It would be practical so I could maintenance charge 2 MCs all winter without having to switch the charger back and forth between two motorcycles.
CTEK has never supplied Y-cables because it is an unsafe solution. With a Y-cable, you connect the batteries of the two motorcycles. You could compare this to the starter cables you use to jump-start a car. If one battery is fully charged and the other is completely drained, there is an incredibly high current between the batteries. But, the difference is that the cable is much thinner than if you have starter cables between 2 cars. There are two risks. The cable could burn off – and then you'd have to pray to a higher power that the cable is the only thing burned. If the Y-cable is fuse protected and the fuse is tripped, you think you're charging even though you're not. This leads to a lot of anger and expense when spring arrives. A better method is to have one COMFORT INDICATOR on each MC. When you check on the bikes, you can then easily see if you need to switch the charger from one MC to the other. Naturally, it would be even easier to have one charger for each MC.


Installation: I have a COMFORT INDICATOR connected to the battery all the time. Is there any risk of the battery discharging?
No, the purpose of the indicator is to allow you to quickly and easily see whether the battery must be charged, thereby reducing the risk of the battery being damaged because of being discharged. The COMFORT INDICATOR uses about 1.5mA. This would cause the battery to discharge only a few minutes faster than without the indicator.; Can I use your COMFORT CONNECT CIG PLUG to charge the battery through the cigarette socket in my car?
Yes, but you should check that you have voltage to the socket even if the vehicle is switched off. If, for example, you can charge a mobile phone or get a GPS to work when the car ignition is switched off, you can also charge the car battery this way.


Choosing a charger: Can I charge a 24V system with two 12V chargers connected in series?
Yes, this is perfectly OK and is actually preferable for the batteries. Connect one charger for each battery.; I'm thinking about installing an electric motor in my sailboat. The motor is run on 48V and I was thinking about either running on eight 6V batteries (deep cycle batteries) or four 12V batteries (type AGM).
Yes, you can use two 24V chargers in your 48V system, but you would get the best results from using four 12V chargers instead. This gives you better control so all batteries obtain the same degree of charge. For two serial-connected batteries, a 24V charger has no control over the voltage being equally distributed over the two batteries. On a wet battery, it is normal for there to be some gassing so that the battery can become fully charged. But, CTEK chargers do not overload the batteries, which prevents major gassing from occurring. If it is not possible to ventilate away the oxy-hydrogen gas, we recommend against using such batteries. Some “wet” batteries have a hose nipple that you can use to connect a hose for venting away the oxy-hydrogen gas. Even though oxy-hydrogen gas is not a problem during normal charging, problems can arise with the battery, e.g. cell fault. In such cases, gassing can be huge if the accident occurs before the charger switches off.

Charger functions

Functions

I have a MXS 3.6/ M45/Zafir 45: The light which indicates 'charging' is lit. The green lamp lights if I press the MODE button repeatedly or if I temporarily cut-off the mains power.

Yes, this is quite right. The battery was charged to more than 90% but not 100% fully charged when charging was interrupted. Explanation: When you start charging a battery, the 'charging' lamp lights until the battery is 100% fully charged. Then the green 'fully charged' lamp lights. The green lamp lights when the charger switches over to 'maintenance charging'. The charger continues in this mode until the voltage of the battery falls below 90% fully charged. The orange 'charging' lamp then lights again and the battery is charged up to 100% again..and again.. The charger restarts and checks how charged the battery is, if you press the MODE button or cut-off the mains power before the battery is fully charged. If the battery is more than 90% charged, then the green 'fully charged' lamp will light. The green light continues to be lit until the voltage falls below 90%. Charging the starts again as described above.

The charger quickly switches over to maintenance charging but without any battery capacity being achieved.

The charger's behaviour can be explained in two different ways, from the battery's point of view: a) Sealed batteries which have lost fluid can behave in this way. The voltage rises quickly but capacity is near zero. This is shown by the battery remaining at a relatively high voltage after having been disconnected from the charger. It can seem as though a 50Ah battery has changed into perhaps a 20Ah battery. Measure the battery voltage with the charger disconnected. If the voltage is 13V or more, then this is probably the correct explanation. The battery is dead and must be replaced. If fluid has been lost, then the upper parts of the battery's plates can be oxidised and therefore dysfunctional. b) A sulphated battery can also result in this behaviour. The sulphate layer insulates and no current flows. Voltage is also measured with the charger disconnected in this situation. But the voltage instead falls quickly to 12V or lower. The charger should, due to the voltage falling so quickly, respond to this by rapidly switching on and off. It is also unlikely of achieving any long term battery life in this case. A CTEK charger tries to 'wake' this type of battery with pulses. The battery will however soon be dead even where it can be brought back to life. Both these faults can be avoided where a CTEK battery charge is used during the out of season period.

When I start charging, the green diode lights steadily and the orange diode flashes quickly. What does this mean?

This can be due to several reasons: 1) Poor contact. Twist the connectors a little. Check that Comfort Connect (or the white plastic contact on the charge cable) is fully home. Also check that contact with the battery is good and that the poles are clean. 2) Sulphated battery is a likely explanation. CTEK chargers have a unique feature for dealing with this. An insulating layer of lead sulphate has formed internally in sulphated batteries. The layer is not fully continuous, as it is still possible to measure a voltage across the battery. The charger, in this situation, pulses out a little energy until the battery starts to receive charging. Batteries which 'do not receive charging' can often be woken in this way. Let the charger charge for an hour. If the charger still flashes, then the battery is probably dead and must be replaced. If the yellow or green lamps light, then you have managed to wake the battery and will probably function. But it is at the end of its life. Chargers which charge using 5A or more trigger alarms (the error lamp lights) if desulphating has continued for more than four hours. This is also to remind you that the remaining battery life is very short. The sulphate crystals are large and no charger in the world can break them down. 3) Fault in battery cell. If a battery starts charging normally as indicated by the orange lamp being lit but which then begins to flash, then this is due to an interruption somewhere. The easiest cause of this is where the connection has fallen off. But it can also be due to an interruption inside the battery. Set the charger in OFF/STANDBY mode and then back to charging. If it is an interruption, then charging does not start.

Can you really just connect up and then forget the charger?

Always check that the charger has switched to maintenance charging mode before leaving the charger unattended and connected for long periods of time. Chargers must be disconnected from batteries where the charger does not switch to maintenance charging within three days. If the charger has switched over to maintenance charging, then everything is as it should be, the battery is probably healthy and will function for a long period of time together with your CTEK charger. If the charger has not switched over to maintenance charging (green lamp lit) within a couple of days, then this is a sign that something is wrong. Possible causes:

A large older type of battery, antimony batteries, behave differently.
Charging takes longer and the battery can be overcharged if large consumers are connected to the battery.
The battery is sulphated from start. Charging will then take longer, as the battery's higher inner resistance limits how much current it can receive.
The battery is spent and needs to be replaced.

Will a CTEK charger remember the settings if you disconnect it from the mains power?

If you disconnect both battery and mains power. The battery must have a voltage above 6V for MXS 3.6 and Zafir 45 chargers to remember settings. Avoid placing a MULTI charger too close to extremely strong electrical fields such as ignition systems, as this can result in the charger losing the settings.

My MXS 5.0/MXS 10 jumped from Float (step 7) to Absorption (step 4) and restarted, is that normal?

In order to keep the battery in good condition The charger will restart in Float if the battery voltage drops below 12.5 V. That may occur if for example the car is locked or locked up while charging.The charger will go back to step 7 (Float) as soon as the battery is 100% charged again. 10 new days of Float will follow, and after that step 8 (Pulse).


General: A CTEK charger is so small. How can it charge so quickly and efficiently, when compared with ordinary chargers?
CTEK's chargers use the same type of technology that computers use to reduce dimensions, to increase power and to charge using a well controlled and 'pure' current. Also, think how big mobile telephones were 15 years ago and how small they are today, and can even so do so much more.; What aspects should I think about when choosing a charger?
Answer: You should think about 3 things when choosing a charger: 1. How large the battery you want to charge is. 2. How discharged it will be before you get a chance to recharge it. 3. How quickly you need the battery to fully recharge. If the battery is large, completely flat and must be charged quickly! Then you should choose a powerful charger such as the MXS 25 or M300. If you instead want to be sure that your motorcycle battery is charged and is kept charged no matter whether you are going to use it tomorrow or in 6 months, then time is not so important and a small charger will work well. XS 8.0 or MXS 3.6 are, for example, good choices.; A supplier only recommends MXS 3.6 up to 75Ah, while it says 120Ah on the box. Why?
New answer. MXS 3.6 works excellently also up to 120Ah. But the MXS 3.6 can seem a bit too slow if the 120Ah is flat and you need to charge it quickly. The less time you have to charge the battery, then the larger the charger you should choose. For example the MXS 7.0 or MXS 10. (This is primarily a weighing up of price and performance.); How deeply discharged can a battery be and still be recharged by a CTEK charger?
A battery is considered to be discharged when the voltage is below 10.5V. It can however provide energy all the way down to 7-8 volts. Most models can handle batteries with voltages down to 2V. XS 0.8 charges from 6V while XC 0.8 charges from 3V. MXS 7, MXS 25 and MXT 14 in Supply mode can still charge from zero volts in the battery. Note that some batteries can be damaged by discharging that is too deep. CTEK chargers try to save these batteries through pulsing, to reduce sulphation or soft-start (some models). A battery which is below these levels is often in poor condition and needs to be replaced.; I think my charger is defective. What should I do?
If the charger does not work, then you should submit a guarantee claim. • The product should be returned with the receipt to the retailer. • The retailer will distribute claim products via distributors to CTEK. • Fill in and print out the guarantee claim form and attach it to the product, to ensure quick and correct fault tracing. • The product guarantee only applies to faults which have not been caused by the user and to claims submitted within the guarantee period. 2, or 5 years depending on product and model. Products purchased before 1 January 2007 have a 2 year guarantee. Refer to the user manual. • CTEK will not repair the product under guarantee if no receipt is attached to the product. • The guarantee ceases if the product has been opened, intentionally damaged or has been modified in any other way. • CTEK does not compensate customers for any incidental or consequential damages which are caused by faulty products or which arise in association with the use of the product. • CTEK will return the product if CTEK’s investigation shows that the product is not faulty. • Faulty products will be repaired or be replaced with equivalent products. • The credited amount can be redeemed at the next purchase. • Products will be returned without being examined if the product‘s guarantee has expired and the product is not clearly faulty. Note that the quality of the product cannot be guaranteed by CTEK. • Faulty units that cannot be repaired are disposed of by CTEK. • If a guarantee claim for a faulty product is not approved, then the charger will only be returned if you specifically request this. You must however cover the postage yourself.; What is ripple and how does it affect batteries?
Ripple is a measurement of the unevenness of the current and voltage supplied by the charger. High current ripple results in the heating up and drying out of a battery and in a shortened lifetime. High voltage ripple results in imprecise charging and can damage a vehicle‘s electronics. CTEK's chargers have a very 'pure' charge current and voltage, i.e. minimal ripple.


Charger settings: Which charger settings should I use?
It depends on battery type, size and area of use. Read more under Battery types & Settings for each charger.

Trouble Shooting Guide


XC 0.8: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: The charger has to be connected to battery for the LED’s to light up.; No LED is lit when the charger is connected to both the power outlet and the battery
Explanation: The battery voltage could be under 4V.
Test: Test against another battery that is fresh.; The charger does not switch from into maintenance charging
Explanation 1: Larger loads are connected to the battery at the same time.
Test: Disconnect the loads from the battery and try to charge again.

Explanation 2: Defective battery.
Test: If possible, measure the voltage on the battery when the charging is completed. If the voltage is under 7V the battery is probably faulty.
Test: Try the charger on another fresh battery.; and is lit (flashing rapidly) simultaneously and there is a ticking sound
Explanation 1: Bad connection.
Test: Move the clamps and make sure there is no loose connection in the quick connector, Comfort Connect.

Explanation 2: The charger is working in the desulphation phase.
Test: Leave the charger to charge for 24h (with some supervision). If the charger does not start charging (one of the LED’s are lit) within 24h the battery is in very poor condition.; switches to after the charge has been stopped
Explanation: When the charger restarts the battery voltage is monitored. If the battery voltage is above 6,5V, the charging will not commence. When the battery is between 6,5V and 7,2V it is considered as fully charged. The charging will automatically start again when the battery voltage drops below 6,5V.; The error LED is lit
Explanation: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.


XS 0.8: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s in the bottom row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2+/-0.5V.
Test: Test the charger on a fresh battery.; is flashing
If no battery or if the battery voltage is too low the led will start to flash to indicate the unit has entered power save mode.
Test: Test the charger on a fresh battery.; is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.

Explanation 3: The charger is not connected to a 12V battery.
Test: Test with a fresh 12V battery.

Explanation 4: The charge cycle is interrupted in step 1.
Test: Test to restart the charge cycle, if it still fails in step 1 the battery is sulphated and needs to be replaced.

Explanation 5: The charge cycle is interrupted in step 4.
Test: Test to restart the charge cycle, if it still fails in step 4 the battery is can’t be charged and needs to be replaced.


XS 800: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: The charger has to be connected to battery for the LED’s to light up.; No LED is lit when the charger is connected to both the power outlet and the battery
Explanation: The battery voltage could be under 6V.
Test: Test against another battery that is fresh.; The charger does not switch from into maintenance charging
Explanation 1: Larger loads are connected to the battery at the same time.
Test: Disconnect the loads from the battery and try to charge again.

Explanation 2: Defective battery.
Test: If possible, measure the voltage on the battery when the charging should be finished. If the voltage is under 7V the battery is most likely faulty.
Test: Try the charger on another fresh battery.; and is lit (flashing rapidly) simultaneously and there is a ticking sound
Explanation 1: Bad connection.
Test: Move the clamps and make sure there is no loose connection in the quick connector, Comfort Connect.

Explanation 2: The charger is working in the desulphation phase.
Test: Leave the charger to charge for 24h (with some supervision). If the charger does not start charging (one of the LED’s are lit) within 24h the battery is in a very poor condition.; switches to after the charge has been stopped
Explanation: When the charger restarts the battery voltage is monitored. If the battery voltage is above 12,9V, the charging will not commence. When the battery is between 12,9V and 14,4V it is considered as fully charged. The charging will automatically start again when the battery voltage drops below 12,9V.; The error LED is lit
Explanation: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the - cable/clamp is connected to the - terminal.


MXS 3.6, MULTI XS 3600, Zafir 45, M45: No LED is lit when the charger is connected only to the battery
Explanation: The charger requires voltage from the battery for the Standby LED to be lit.
Test: Connect the charger to a fresh battery.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s at the lower row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED is lit when the charger is connected to both the power outlet and the battery
Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Test against another battery that is fresh.; The charger does not switch from into maintenance charging
Explanation 1: Larger loads are connected to the battery at the same time.
Test: Disconnect the loads from the battery and try to charge again.

Explanation 2: Defective battery.
Test: If possible, measure the voltage on the battery when the charging should be completed. If the voltage is under 14,1V the battery is most likely faulty.
Test: Try the charger on another fresh battery.; and is lit (flashing rapidly) simultaneously
Explanation 1: Bad connection.
Test: Move the clamps and make sure there is no loose connection in the quick connector, Comfort Connect.

Explanation 2: The charger is working in the desulphation phase.
Test: Leave the charger to charge for 24h (with some supervision). If the charger does not start charging (one of the LED’s are lit) within 24h the battery is in a very poor condition.; switches to after the charge has been stopped
Explanation: When the charger restarts the battery voltage is monitored. If the voltage is above 12,9V, the charging will not commence. When the battery is between 12,9V and 14,4V it is seen as fully charged. The charging will automatically start again when the battery voltage drops below 12,9V.; The charger goes into Standby mode after the power is cut and the charging does not start again
Explanation: The charger will turn into Standby if the voltage in the battery is below 6V when the power is back on.
/ Test: Start the charging again by pressing on the mode button.; The error LED is lit
Explanation: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.


MXS 5.0, MXS 5.0 CHECK, MXS 5.0 Polar, MXS 4003: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s in the bottom row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Test the charger on a fresh battery.; is flashing
If no battery or if the battery voltage is too low the led will start to flash to indicate the unit has entered power save mode.
Test: Test the charger on a fresh battery.; is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.

Explanation 3: The charger is not connected to a 12V battery.
Test: Test with a fresh 12V battery.

Explanation 4: The charge cycle is interrupted in step 1.
Test: Test to restart the charge cycle with the mode button, if it still fails in step 1 the battery is sulphated and needs to be replaced.

Explanation 5: The charge cycle is interrupted in step 2.
Test: Test to restart the charge cycle with the mode button, if it still fails in step 2 the battery is can’t be charged and needs to be replaced.

Explanation 6: The charge cycle is interrupted in step 5.

Explanation 6.1: Large loads are connected to the battery and drain the voltage.
Test: Disconnect the loads and try charging again.

Explanation 6.2: The battery cannot retain the charge provided.


MXS 7.0, MULTI XS 7000, Zafir 100, M100: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s at the lower row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the lowest row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Try to charge the battery in Supply mode for approximately 5 min. Then try regular charging.
Test: Test the charger on a fresh battery.; is lit for 4 hours and then turns into error mode
If the battery voltage is not above 12,5V after 4h the charger will turn into error mode, because the voltage has not increased in the way it should have done.

Explanation 1: The battery is too large in relation to the capacity of the charger.
Test: Make sure that the battery/batteries size is not larger than the recommendations for Multi XS 7000 (225Ah).
Test: Try to restart the charger because the charger might need more time to charge the battery.

Explanation 2: Larger loads are connected to the battery.
Test: Disconnect the battery and try to charge it without the loads.
Test: Try to restart the charger because the charger might need more time to charge the battery.

Explanation 3: If the battery is warm and/or is boiling heavily during the charging, it is most likely due to a defective cell in the battery.
Test: Change the battery.; is flashing for 4 hours, then turns into error mode
Explanation: The battery is probably too sulphated to revive. The battery is faulty and it is time to change it.; is lit and then turns into error mode
The analysis phase is testing if the battery can retain the charger given.

Explanation 1: Large loads are connected to the battery and are draining the voltage.
Test: Disconnect the battery and try charging again.

Explanation 2: The battery cannot retain the charge given.
Test: The battery needs replacing.; The error LED is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: The clamps are short circuited.

Explanation 3: For chargers of the older type the error mode is flashing when only the plug is connected.


MXT 4.0, MULTI XT 4000: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s at the lower row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the lowest row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Test the charger on a fresh battery.; is lit for 4 hours and then turns into error mode
If the battery voltage is not above 25,5V after 4h the charger will turn into error mode, because the voltage has not increased the way it should have done.

Explanation 1: The battery is too large in relation to the charger capacity.
Test: Make sure that the battery/batteries are not larger than the recommendations for Multi XT 4000 (100Ah).
Test: Try to restart the charger because the charger might need more time to charge the battery.

Explanation 2: Larger loads are connected to the battery.
Test: Disconnect the battery and try to charge it without the loads.
Test: Try to restart the charging, the charger might need more time to charge the battery.

Explanation 3: If the battery is warm and/or is boiling heavily during the charging, it is most likely a defective cell in the battery.
Test: Change the battery.; is flashing, then turns
Explanation: The battery is probably too sulphated to revive. The battery is faulty and it is time to change it.; is lit and then turns into error mode
The analysis phase is testing if the battery can retain the charger given.

Explanation 1: Large loads are connected to the battery and draining the voltage.
Test: Disconnect the battery and try charging again.

Explanation 2: The battery cannot retain the charger given.
Test: The battery needs replacing.; The error LED is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: The clamps are short circuited.

Explanation 3: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.


MXS 10: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s in the bottom row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Try to charge the battery in Supply mode for approximately 5 min. Then try regular charging.
Test: Test the charger on a fresh battery.; is flashing
If no battery or if the battery voltage is too low the led will start to flash to indicate the unit has entered power save mode.
Test: Test the charger on a fresh battery.; is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.

Explanation 3: The charger is not connected to a 12V battery.
Test: Test with a fresh 12V battery.

Explanation 4: The charge cycle is interrupted in step 1.
Test: Test to restart the charge cycle with the mode button, if it still fails in step 1 the battery is sulphated and needs to be replaced.

Explanation 5: The charge cycle is interrupted in step 2.
Test: Test to restart the charge cycle with the mode button, if it still fails in step 2 the battery is can’t be charged and needs to be replaced.

Explanation 6: The charge cycle is interrupted in step 5.

Explanation 6.1: Large loads are connected to the battery and drain the voltage.
Test: Disconnect the loads and try charging again.

Explanation 6.2: The battery cannot retain the charge provided.; Temperature LED is lit
Explanation: This led is turned on automatically when the temp sensor is connected.; Temperature LED is not lit
Explanation: The temperature sensor is disconnected or has been damaged. The charger will assume room temperature and charge without temperature compensation.; Temperature LED is flashing
Explanation: The temperature is above + 65 °C. The current is reduced until the temperature has dropped below + 65 °C. The charger reverts to normal charging current when the temperature drops below + 65 °C.


MXS 25, MULTI XS 25000: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s at the lower row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Try to charge the battery in Supply mode for approximately 5 min. Then try regular charging.
Test: Test the charger on a fresh battery.; is lit for 4 hours and then turns into error mode
If the battery voltage is not above 12,5V after 4h the charger will turn into error mode, because the voltage has not increased the way it should have done.

Explanation 1: The battery is too large in relation to the chargers capacity.
Test: Make sure that the battery/batteries are not larger than the recommendations for MXS 25 and Multi XS 25000 (500Ah).
Test: Try to restart the charger because the charger might need more time to charge the battery.

Explanation 2: Larger loads are connected to the battery.
Test: Disconnect the battery and try to charge it without the loads.
Test: Try to restart the charging, the charger might need more time to charge the battery.

Explanation 3: If the battery is warm and/or is boiling heavily during the charging, it is most likely a faulty cell in the battery.
Test: Change the battery.; is flashing, then turns into error mode
Explanation: The battery is probably too sulphated to revive. The battery is faulty and it is time to change it.; is lit and then turns into error mode
The analysis phase is testing if the battery can retain the charge given.

Explanation 1: Large loads are connected to the battery and drain the voltage.
Test: Disconnect the battery and try charging again.

Explanation 2: The battery cannot retain the charge given.
Test: The battery needs replacing.; The error LED is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.

Explanation 3: The clamps are short circuited in Supply mode.
Test: Separate the clamps.; Temperature LED is lit
Explanation Multi XS 25000: DC interruption or short circuit in the cable.

Explanation MXS 25: This is normal, the LED is on indicating that the temperature sensor is activated. If the LED is turned off here is a DC interruption or short circuit in the cable.; Temperature LED is flashing
Explanation: The temperature is above + 65 °C. The charging is interrupted. Press the MODE button to restart charging when the temperature has dropped below + 65 °C.


M200, M300: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s at the lower row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 2 +/- 0.5V.
Test: Test the charger on a fresh battery.; is lit for 4 hours and then turns into error mode
If the battery voltage is not above 12,5V after 4h the charger will turn into error mode, because the voltage has not increased the way it should have done.

Explanation 1: The battery is too large in relation to the chargers capacity.
Test: Make sure that the battery/batteries are not larger than the recommendations for M200 and M300 (500Ah).
Test: Try to restart the charger because the charger might need more time to charge the battery.

Explanation 2: Larger loads are connected to the battery.
Test: Disconnect the battery and try to charge it without the loads.
Test: Try to restart the charging, the charger might need more time to charge the battery.

Explanation 3: If the battery is warm and/or is boiling heavily during the charging, it is most likely a faulty cell in the battery.
Test: Change the battery.; is flashing, then turns into error mode
Explanation: The battery is probably too sulphated to revive. The battery is faulty and it is time to change it.; is lit and then turns into error mode
The analysis phase is testing if the battery can retain the charge given.

Explanation 1: Large loads are connected to the battery and drain the voltage.
Test: Disconnect the battery and try charging again.

Explanation 2: The battery cannot retain the charge given.
Test: The battery needs replacing.; The error LED is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.

Explanation 3: The clamps are short circuited in Supply mode.
Test: Separate the clamps.; Temperature LED is lit
Please note that the function of temperature sensor has changed for M200 and M300. The charger will indicate differently depending on when it was purchased.

Explanation M200 and M300 purchased before 2011: DC interruption or short circuit in the cable.

Explanation M200 and M300 purchased from 2012 and later: This is normal, the LED is on indicating that the temperature sensor is activated. If the LED is turned off here is a DC interruption or short circuit in the cable.; Temperature LED is flashing
Explanation M200 and M300 purchased from 2012 and later: The temperature is above + 65 °C. The charging is interrupted. Press the MODE button to restart charging when the temperature has dropped below + 65 °C.


MXT 14, MULTI XT 14000: No LED is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s to be lit.; No LED is lit when the charger is connected only to the power outlet
Explanation: One of the LED’s in the bottom row should light up when the charger is connected to the power outlet.
Test: Make sure that there is power from the power outlet.; No LED’s are lit on the top row when the charger is connected to both the power outlet and the battery
The LED’s on the bottom row are lit and you can change charging mode. None of the LED’s in the top row, indicating charging status, are lit.

Explanation: The battery voltage could be under 7V.
Test: Try to charge the battery in Supply mode for approximately 5 min. Then try regular charging.
Test: Test the charger on a fresh battery.; is lit for 4 hours and then turns into error mode
If the battery voltage is not above 25,5V after 4h the charger will go into error mode, because the voltage has not increased the way it should have done.

Explanation 1: The battery is too large in relation to the capacity of the chargers.
Test: Make sure that the battery/batteries are not larger than the recommendations for XT 14000 / Multi XT 14000 (500Ah).
Test: Try to restart the charger because the charger might need some more time to charge the battery.

Explanation 2: Larger loads are connected to the battery.
Test: Disconnect the battery and try to charge it without the loads.
Test: Try to restart the charging, the charger might need more time to charge the battery.

Explanation 3: If the battery is warm and/or is boiling heavily during the charging, it is most likely a defective cell in the battery.
Test: Change the battery.; is flashing, then turns
Explanation: The battery is probably too sulphated to revive. The battery is faulty and it is time to change it.; is lit and then turns into error mode
The analysis phase is testing if the battery can retain the charge given.

Explanation 1: Large loads are connected to the battery and drain the voltage.
Test: Disconnect the battery and try charging again.

Explanation 2: The battery cannot retain the charge provided.; The error LED is lit
Explanation 1: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the – cable/clamp is connected to the – terminal.

Explanation 2: Loads are connected to the battery which requires more power than the charger can provide.
Test: Turn off or disconnect the loads when charging.; Temperature LED is lit
Explanation Multi XT 14000: DC interruption or short circuit in the cable.

Explanation MXT 14: This is normal, the LED is on indicating that the temperature sensor is activated. If the LED is turned off here is a DC interruption or short circuit in the cable.; Temperature LED is flashing
Explanation: The temperature is above + 65 °C. The charging is interrupted. Press the MODE button to restart charging when the temperature has dropped below + 65 °C.


MXTS 70: No LED or display is lit when the charger is connected only to the battery
Explanation: The plug has to be connected for the LED’s and the displays to be lit.; No LED or display is lit when the charger is connected only to the power outlet
Explanation: The displays and LED’s should light up when the charger is connected to the power outlet. The fans should also turn on.
Test: Make sure that there is power from the power outlet.; is lit
Explanation: This led is lit when the charger has been set to a current less than the maximum.; is lit
Explanation: This led is lit when the charging has been stopped or not started. Press the START/PAUSE button to start or resume.; is lit
This indication always has an explanation in the Ah & info display.

E01: Reverse polarity.
Test: Make sure that the + cable/clamp is connected to the + terminal and the - cable/clamp is connected to the - terminal.

E02: Over voltage. The battery connected has a higher voltage than the selected charge program.
Test: Make sure that the battery and the selected charge program corresponds to each other.

E03: Time out step 1: Desulphation. The battery is sulphated and can´t be charged correct.
Test: Try to restart the charge cycle, if it still fails in step 1 the battery is sulphated and needs to be replaced.

E04: Time out step 2. Soft start. The battery can´t be charged correct.
Test: Try to restart the charge cycle, if it still fails in step 1 the battery is sulphated and needs to be replaced.

E05: Analyze. The charger can´t keep the charge.
Test: Remove all parallel loads on the battery and restart the charge cycle. If the analyze fails again the battery needs to be replaced.

E06: battery overheated. The charger has detected a too warm battery, over + 60 °C. Push Pause/Start to resume charging when temperature is below.
Test: Make sure that it is not the ambient that is too warm. If that is not the case the battery need to be replaced.

E07: Low battery voltage in supply program. The battery connected has too low voltage to continue. The battery connected is either a 12V and the charger is in 24V mode or the parallel loads are too high.
Test: If a 12V battery is connected check if the unit is in 24V mode. Try to remove all parallel loads.

E08: Over current in supply. The charger has switched off the output due to too high current.
Test: Make sure that the clamps not are shortened. Also check if there are massive parallel loads on the battery.

E99: Over voltage protection. If battery voltage is below 17V the ERROR LED is lit when 24V mode has been selected.
Press the START/PAUSE button to proceed with in 12V mode. To change to 24V mode press INCREASE or DECREASE.; Temperature LED is lit
Explanation: This led is turned on automatically when the temp sensor is connected.; Temperature LED is not lit
Explanation: The temperature sensor is disconnected or has been damaged. The charger will assume room temperature and charge without temperature compensation.


D250S DUAL: Power LED is not lit
Explanation: The target battery voltage must be above 9V.; The Power LEDs are flashing rapidly or glowing faint
Explanation: The charger has entered power save mode due to low voltage.; The charger does not start charging
Explanation: In order to start charging the supply voltage needs to be above 13.1V on the supply battery input or above 11.5V on the solar input. The voltage on the target battery also needs to above 5V. The solar voltage also needs to be higher than the alternator input voltage.
Test: Test Use a voltmeter to verify that the voltages are within the levels specified above.; The charger does not stop charging the target battery even though the alternator or charger on the supply battery has been turned off
When charging of the supply battery is turned off the voltage will drop. The output power of the charger is dependent on the input voltage. With lower input voltage the output power is lower. Due to this it may take some time until the charger stops. It will however not drain the supply battery, the charger will turn off when the voltage has dropped below 12.8V. If there is power on the solar panel, this will be used to charge the target battery.; is flashing
Explanation: The charger has detected a problem. This LED is always flashing with some other LEDs lit to tell what the problem is.

If only the power on lamp is lit then the temperature at the target battery is too high. The charger will not charge the battery if the temperature is above 65 °C, as soon as the temperature is lower, the charging will automatically restart.

If the alternator or solar LED or both are lit when the error led is flashing a connection problem is detected with the target battery, check the connections.


SMARTPASS: The Power LED is flashing rapidly or glowing faint
Explanation: The charger has entered power save mode due to low voltage. There is no charger or alternator turned on for the supply battery.; The SMARTPASS does not start charging
Explanation: In order to start charging the supply voltage needs to be above 13.1V. The voltage on the target battery also needs to above 5V.
Test: Test Use a voltmeter to verify that the voltages are within the levels specified above.; The SMARTPASS does not stop charging the target battery even though the alternator or charger on the supply battery has been turned off
When charging of the supply battery is turned off the voltage will drop. The SMARTPASS will turn off when the voltage has dropped below 12.8V, if there are no parallel loads this will take some time.; The SMARTPASS does not supply the consumers from the consumer battery
The SMARTPASS will turn off the consumer output if the consumer battery reaches 11.5V. This will prevent the battery from being damaged due to being drained too much. To turn on the consumer output again the consumer battery needs to be charged.; is lit
Explanation: The SMARTPASS has detected a problem. This LED is always lit with some other LEDs flashing to tell what the problem is.

Led 1 flashing: A problem is detected with the service battery. The current to the battery is too high or the SMARTPASS is overheated. If the current is too high the SMARTPASS will try to start charging the battery five times. If all five tests fails the SMARTPASS needs to be disconnected from both batteries before it can restart. If this is the case check the cables for short circuit. If the SMARTPASS is overheated charging will automatically restart when the temperature has dropped.

Led 2 flashing: A problem is detected with the consumer output, while the consumer output is connected to the starter battery input. The current to the output is too high or the SMARTPASS is overheated. If the current is too high the SMARTPASS will try to start charging the battery five times. If all five tests fails the SMARTPASS needs to be disconnected from both batteries before it can restart. If this is the case check the cables for short circuit, there could also be too many consumers connected. If the SMARTPASS is overheated output will automatically turn on when the temperature has dropped.

Led 3 flashing: A problem is detected with the starter battery while maintenance charging. The current to the battery is too high or the SMARTPASS is overheated. If the current is too high the SMARTPASS will try to start charging the battery five times. If all five tests fail the SMARTPASS needs to be disconnected from both batteries before it can restart. If this is the case check the cables for short circuit. If the SMARTPASS is overheated output will automatically turn on when the temperature has dropped.

Led 4 flashing: A problem is detected with the consumer output, while the consumer output is connected to the consumer battery. The current to the output is too high or the SMARTPASS is overheated. If the current is too high the SMARTPASS will try to start charging the battery five times. If all five tests fails the SMARTPASS needs to be disconnected from both batteries before it can restart. If this is the case check the cables for short circuit, there could also be too many consumers connected. If the SMARTPASS is overheated output will automatically turn on when the temperature has dropped. It could also mean that the battery voltage on the consumer battery is too low, this case is discussed above.

Led 1, 3 and 4 flashing: The temperature on the service battery is too high. The SMARTPASS will not charge the battery if the temperature is above 65 °C, as soon as the temperature is lower, the charging will automatically restart.

Error lamp
Power lamp
1. Service battery charging lamp
2. Alternator battery consumption
3. Alternator battery charging lamp
4. Service battery consumption lamp

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