CTEK CS ONE (Gen 2) Review

CTEK's MXS 5.0 is the charger people buy once and keep for fifteen years, and its one real limitation is that it asks you to know things: which mode the battery needs, which clamp is positive, and whether it's lead-acid at all. The CS ONE line removes the questions. Connect either clamp to either terminal, and the charger's APTO logic figures out the polarity, identifies the chemistry — including the LiFePO4 packs in powersports and some aftermarket setups the MXS 5.0 can't touch — and runs the appropriate program at up to 8 amps, nearly double the MXS rate. The temperature sensor adjusts voltage for the cold, as you'd expect from a charger rated to -22°F.

What makes the Gen 2 different from the original CS ONE is the radio. The first version was Bluetooth-only, which meant the app worked from the garage and nowhere else. Gen 2 adds Wi-Fi, so once the charger is on your home network the CTEK app shows live voltage and current, charging stage, and a history log from anywhere, with push notifications when something changes. That's the feature that justifies the model to a specific buyer: someone with a car that sits from November to April in a garage they don't visit, who wants confirmation rather than faith. The advanced modes — Recond for a stratified battery, Wake Up for one so flat the charger can't see it, Supply for holding voltage during a battery swap — are all selected from the phone.

The honest question is whether that's worth three times the price of the MXS 5.0. For a daily driver that gets a weekly top-off, it isn't; the NOCO Genius5 and the MXS 5.0 do that job for far less and don't need a Wi-Fi password. The polarity-free promise also has fine print — it holds in charging mode, but the Wake Up and Supply modes still require correct clamp placement — and CTEK's habit of selling the wall mount, case, and longer leads separately adds up. Where the CS ONE Gen 2 earns its cost is the second or third vehicle you want to stop worrying about: it's the most capable, most foolproof maintainer here, and the only one that will tell your phone the battery is fine.