Trying to wake up the CS ONE via the CTEK app, but the battery doesn't start.    
Disconnect the battery from the vehicle or from the load and run wake up procedure again. If it still does not work, the battery might be broken or has closed down (LiFePO4). CTEK recommend to get the battery tested - it may need replacing.

The CS ONE shows two steady red lights, what does that mean?    
If the indication shows immediately when attempting a charge, check that the connection is not short circuited or the battery voltage is higher than 16V. If the indication shows some time after charging has started, this means the charge is interupted as there might be something wrong with the battery. Disconnect all possible consumers and try again. If the problem persists, CTEK recommend to get the battery tested - it may need replacing.

The CS ONE shows two BLINKING red lights, what does that mean?    
This shows that the CS ONE does not work as it should. Please disconnect from battery and mains and wait several minutes, reconnect and try again. If this happens every time the CS ONE is used, please contact the dealer, the CS ONE may be broken and need to be replaced.

The CS ONE shows two BLINKING blue lights, what does that mean?    
This can be seen during the first 2 minutes after connecting, and tells you that the CS ONE is ready to be paired with a mobile device via bluetooth.

What is the bluetooth range of the CS ONE?    
The bluetooth range of the CS ONE is approximately 10 meters. 

Is there WiFi-connection to the CS ONE?    
No. The mobile device will need to be close to the CS ONE when using the app.

The white lights keeps circling on the CS ONE after the battery is connected, why?    
The circling white light on the CS ONE is an indication for poor contact between the battery and the charger - or a battery drained too low (<1,5V for lead acid and a lithium that has closed down, Under Voltage Protection).
Check all connection points, including connections into the CS ONE. If the problem persists, using the free CTEK APP begin the 'WAKE UP' procedure to start the charge. If the problem persists, CTEK recommend to get the battery tested - it may need replacing."

What does it mean when the 'START' indicator is blinking?    
It means that the battery does not have enough power to start the vehicle. Wait until the 'START' indicator becomes permanantly lit.

What does it mean when the 'START' indicator is permenantly lit and  '>8' is blinking?    
It means that the battery will have power enough to start the vehicle and that the CS ONE is charging the battery.

What does it mean when '6' is lit and '4' is blinking    
It means that it is up to 6 hours left before the battery is fully charged. The CS ONE is charging the battery at this time.

What does it mean when '4' is lit and '2' is blinking?    
It means that it is up to 4 hours left before the battery is fully charged. The CS ONE is charging the battery at this time.

What does it mean when '2' is lit and '1' is blinking?    
It means that it is up to 2 hours left before the battery is fully charged. The CS ONE is charging the battery at this time.

What does it mean when all LED segments are pulsing slowly with a white colour?    
This means the battery is fully charged and the CS ONE has gone into maintenance care.

The charger shows two steady white lights, '<8' and '2', what does that mean?    
It means that the CTEK APP is being used and controlling the CS ONE.

I have used the 'SUPPLY' function from the CTEK APP but it will not go back to charging, why?    
After using the 'SUPPLY' function from the CTEK APP, choose the operation 'RESET TO APTO' to make the battery charge again.

The CTEK APP cannot find the CS ONE, the status is shown as being offline, why?    
Check that Bluetooth is active on the mobile device. Check that the mobile device and the CS ONE are within the receiving range of the Bluetooth. 

Cannot choose the 'WAKE UP' function on the app, why is it missing?    
WAKE UP' is only available when the CS ONE cannot find the battery. Open the app and start the CS ONE - but doesn't connect the charger to the battery (or to recommended charge points) it will show up on the app directly.

How does the 'SUPPLY' function work in the CTEK APP?    
In 'SUPPLY' the CS ONE works as a supply unit, giving out a constant voltage of 13,6 volt and as much current as required (max 8 ampere). There is also an output power limit of 100 watt.

How does the 'RECOND' function work in the CTEK APP?    
The 'RECOND' function should only be used on wet  lead acid batteries (Not Lithium LiFePO4, GEL or AGM batteries). In 'RECOND' the CS ONE will firstly go through all of the charging steps until the battery is fully charged. The voltage is then raised in a controlled way to prevent acid stratification and rolong battery life. 'RECOND' should only be used 1-2 times per year."

What type of batteries can CS ONE charge?    
The CS ONE charges all types of 12V batteries from 3Ah up to 180Ah.

What is 'POLARITY FREE'?    
'POLARITY FREE' means it does not matter which clamp is connected to which connection point under the bonnet, it will work either way. Please note that if the CS ONE is used togheter with the CTEK APP, there are functions where the CS ONE is no longer polarity free."

How should the CS ONE be connected to the battery, as both clamps are black?    
The CS ONE is 'POLARITY FREE', so it does not matter which clamp is connected to which connection point under the bonnet, it will work either way. 

I have a lithium battery, how do I choose correct option on the CS ONE?    
The CS ONE works with both lead acid and lithium (LiFePO4) batteries, there is no need to select an option - the charger determines the battery type connected and give the best possible charge.

I have a 3Ah battery, but I can't find a mode for small batteries on the CS ONE. How do I choose?    
The CS ONE uses APTO technology to detrime the battery size, and adapt the maximum charge current to the battery capacity. There is no need to select an option.

Does the CS ONE work with all my CTEK accessories, that I use together with my other CTEK chargers?    
The optional CS CONNECT ADAPTER CABLE will be required to make the CS ONE compatible with the CTEK accessories.

How long is the warranty on CS ONE?    
The CS ONE comes with a 5-year warranty.

Do I need to register my charger to thave the 5 year warranty time?    
No, should any issues arise, please contact you supplier. If the supplier is unable to help, please contact CTEK directly.

What is APTO technology?    
APTO technology is what makes the CS ONE do all the thinking for you. It determines the  type and capacity of the battery and it's needs, and automatically delivers a customised charging program to maximize the battery performance. 

There is a "i" sign on my app, what does this mean?    
This means there is more information available.

The CS ONE shows two steady blue lights, what does that mean?    
Bluetooth connection is verified