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CTEK’s CS FREE is the world’s first multi-functional portable battery charger and smart maintainer with Adaptive Boost technology. You can charge and maintain any 12V lead acid or lithium battery anywhere using mains, solar or leisure battery power. And if your battery’s flat, CS FREE’s revolutionary Adaptive Boost technology will work out the safest and quickest way to power up your battery to get you going within 15 minutes.



Multi-functional portable charger and smart maintainer with Adaptive Boost technology

CS FREE gives you the freedom to charge and maintain any 12V lead acid or lithium battery wherever you are – even if you’re nowhere near a power outlet. Use it as a portable charger to top up your battery with mains power, or hook it up to a solar panel kit or 12V battery for complete charging freedom anywhere you go. CS FREE also features our revolutionary Adaptive Boost technology so if your vehicle won’t start, just connect it up and CS FREE will automatically analyse the state of your battery. It’ll then work out the safest and quickest way to give it the power it needs to start your vehicle within 15 minutes. Unlike most ‘boosters’, CS FREE is sensitive and safe, so it avoids damaging your battery or your vehicle’s electronics by only giving it the charge it needs to get you going. CS FREE is also a smart maintainer and hi-tech powerbank to keep your battery and tech powered up so they’re always ready to go.


  • Works with all types of 12V lead acid and lithium batteries
  • Suitable for use on motorbikes, cars, leisure vehicles and vans
  • Countdown function shows you how long there is left before your battery is fully charged
  • Can be left safely connected for smart maintenance charging
  • Can be charged and used with 12V accessory socket, service battery or solar panel
  • USB-C and USB-A outputs for charging tech like laptops, smartphones and tablets
  • Easy to use, easy to operate, easy to understand
  • No modes to select – just connect and the CS FREE will do the rest
  • Complete range of accessories available for mains free charging and handy storage
  • New ergonomic design with a tough and durable case.
  • Easy to carry around or wall mount using the optional CS Wall Mount
  • 2 year ‘peace of mind’ warranty

Technical data

Battery capacity
10-130 Ah
Battery capacity CEC-400
10-130 Ah
Charging category
AC charging; DC charging
Battery voltage
12 V
Battery chemistry
Lead acid; Lithium-ion
Ambient storage temperature
-20 °C to +45 °C (-4 °F to +113 °F)
Ambient operating temperature
-20 ˚C to +50 ˚C (- 4 °F to +122 °F)
Natural convection
USB-C, 5 VDC – 25 VDC, 3 ADC/60 W max
12 V, 20 A/240 W max
Start voltage
3.0 V
50-60 Hz
Battery types
12 V:; WET; MF; Ca/Ca; AGM; EFB; GEL; LiFePO₄
Enclosure material
Rated voltage (Input)
100 VAC – 240 VAC
Degree of protection
Dimensions (L x W x H)
9.8 x 3.9 x 3.1 in
Dimensions (L x W x H)
248 x 98 x 78 mm
Dimensions (L x W x H)
9.8 x 3.9 x 3.1 pulgadas
Net weight (unit with cables)
1.4 kg
User interface
LED symbols
Net weight (unit with cables)
3 lbs
Net weight (unit with cables)
3 libras
Detachable charging cable length (ouput)
2 m
Internal battery capacity
66 Wh
Internal battery cell chemistry
Polymer Lithium-Ion
Internal battery cell type
Pouch Cell
Internal battery charge temperature
0˚C to +45˚C (32˚F to 113˚F)
Internal battery discharge temperature
-20 ˚C to +50 ˚C (- 4 °F to +122 °F)
Internal battery life span
300 cycles, 80%
Internal battery shelf life
1 year
Internal battery weight
0.5 kg
Mains adapter cable length
1 m
Mains adapter cable type
Mains adapter input
100 VAC – 240 VAC, 50 Hz – 60 Hz, 60 W max
Mains adapter output
USB-C, 5 VDC – 20 VDC, 3 ADC, 60 W max
USB-C input
USB-A Output
5 VDC, 2.4 ADC/12 W max
USB-C Output
5 VDC, 9 VDC, 12 VDC, 15 VDC, 20 VDC, 3 ADC/60 W max
2 years
Warranty, info
Limited Warranty
CTEK issues a limited warranty to the original purchaser of the product. Depending on the product, the limited warranty period will vary. The limited warranty is not transferable. The warranty applies to manufacturing faults and material defects. The warranty is void if the product has been handled carelessly or repaired by anyone other than CTEK or its authorized representatives. CTEK makes no warranty other than this limited warranty and is not liable for any other costs other than those mentioned above, i.e. no consequential damages. Moreover, CTEK is not obligated to any other warranty other than this warranty.

Suitable accessories