Battery chargers and maintainers come in various guises, but CTEK are still the daddy of the industry. Started over 20 years ago in Sweden, CTEK was the first battery charger to use electronic pulse technology, paving the way for modern ‘smart’ chargers.
Gen 2 of their flagship CTEK CS One aims to refine things even further, adding Wi-Fi connectivity to an already clever piece of kit.
What is it?
CTEK CS One Gen 2 is an ultra-smart battery charger and maintainer designed to keep your car, motorcycle, van, or even a leisure battery fully charged and in peak health. It can recondition flat lead-acid batteries, wake up dead lithium ones, and act as a 12v power supply when swapping out a vehicle battery.
APTO (Adaptive Charging) technology handles all the clever heavy lifting automatically. APTO means you don’t need to worry about positive and negative clamps anymore; attach them anywhere, and the charger figures out polarity on its own. It also automatically identifies battery chemistry and size, preventing costly mistakes.
Wi-Fi and Bluetooth connectivity link the CS One Gen 2 to the same CTEK app from the first gen, letting you track charging progress remotely, receive push notifications, view activity history, and access advanced modes like RECOND, WAKE UP, and SUPPLY.
How does it work?
Simply plug the CS One Gen 2 into the mains, attach the clamps to the battery terminals (either way round), and that’s it.
No physical buttons clutter the casing. A circular status display lights up different segments to show remaining charge time.
Being polarity-free means there is no danger of putting the red clamp on the negative post or vice versa – not that this should be tricky, but some people still manage to struggle with the most basic tasks in this world!
A worthy note remains that CS One Gen 2 isn’t 100% polarity-free across every single mode. If you activate ‘WAKE UP’ or ‘SUPPLY’ modes via the app, the shorter lead must attach to the negative terminal. App settings do warn you about this, but it’s worth remembering amid all the ‘polarity-free’ branding.
Clamps remain completely spark-free if brought into contact with each other.
In terms of battery size, CS One Gen 2 is fully adaptive up to 8 Amps for batteries up to 180Ah. Charging works across all 12v battery types: Lead Acid, Wet, MF CA/CA, AGM, Gel, and EFB, alongside Lithium LiFePO4 cells.
Dumb chargers can destroy lithium batteries in pretty spectacular fashion, so having automatic chemistry detection offers huge peace of mind.
Built-in sensors monitor battery health and automatically adjust charging voltage based on ambient temperature.
What’s it like?
Physically, the unit retains its sleek, gloss black aesthetic and IP65 weatherproof rating. Dust protection is top-tier with rubber bungs on all the ends, and it will handle water sprays, making it fine for garage or outdoor use.
The main display is super clean and easy to read, illuminating six countdown segments along with a ‘Start’ indicator that pulses while assessing battery condition.
Connecting via the app is where Gen 2 delivers its biggest upgrade. Previous Bluetooth-only range meant staying within a few metres of the charger. Wi-Fi integration changes everything: you can now monitor charge progress, review history logs, or receive push notifications right from your sofa, workshop, or office.
Testing the trickle charge on a second car was a breeze, the app connectivity stayed rock-solid, delivering live updates on voltage and current without the annoying crashes experienced on the very first version of the CTEK app.
There are also some handy new additions, like reminders to charge your battery and I also discovered you can set the output power to max rather than intelligent – helpful if you need to try and jump-start and old battery with a few volts.
When it comes to sheer ease of use, CS One Gen 2 is almost impossible to fault. Automation takes away all guesswork, making it brilliant for daily drivers, fleet vehicles, or classic cars with unclear terminal markings.
Our main gripes, however, (as with the original CTEK CS One) still focus heavily on price and box contents. At around £199 to £260, you receive just the charger in a cardboard box.
How do I store it nicely when it’s not in use? In the cardboard box again?
How do I mount it to a wall without paying extra?
You are still expected to buy essential accessories separately:
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CTEK CS One Wall Mount – £29.90
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CTEK CS One Bumper – £17.90
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CTEK CS One U Terminal – £13.90
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CTEK CS Connect Adapter Cable – £9.90
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CTEK CS Storage Case – £29.90
Adding over £100 in extra accessories to an already expensive premium device remains hard to swallow. Come on, guys—throw in a bumper or storage bag at this price point.
Apart from being devoid of accessories, the CS One Gen 2 is a magnificent bit of engineering. Future-proofing with LiFePO4 support combined with Wi-Fi convenience makes it the ultimate ‘set and forget’ charger.
Where can I get one?
You can purchase the CTEK CS One Gen 2 directly from CTEK, or via Amazon, SportsBikeShop, and Halfords.
