About this replacement
Karcher OC 3 Foldable Mobile Cleaner — 7.4V Li-ion Replacement Battery
This listing covers a 7.4V 2000mAh lithium-ion replacement battery for the Karcher OC 3 Foldable low-pressure mobile cleaner. The OC 3 Foldable is a cordless outdoor cleaner used on vehicles, tools, façades, garden machines, and pets — it needs a steady 7.4V supply to drive the pump under load. Capacity is 2000mAh (14.8Wh), matching the original specification.
- OC 3 Foldable compatibility: The OC 3 Foldable platform uses a single internal 7.4V lithium-ion pack with a dedicated BMS — this replacement matches that voltage rail, connector footprint, and cell configuration.
- Bench tested on actual hardware: We ran full charge and discharge cycles — the BMS held voltage steady under pump load and triggered the low-voltage cutoff cleanly without drop-out events.
- First-charge protocol for Li-ion pump batteries: Charge fully before first use. Lithium-ion cells in pump applications benefit from a complete initial cycle to let the BMS calibrate its state-of-charge tracking accurately.
Why voltage accuracy matters in a low-pressure pump system
The OC 3 Foldable relies on consistent voltage to maintain pump pressure. A cell pack that sags under load causes pressure fluctuations mid-clean. These cells are matched for internal resistance to keep voltage stable across the full discharge curve, not just at rest.
LED charge indicator showing incorrect level after replacement
If the OC 3's LED display reads inaccurately after fitting a new battery, the BMS has not yet calibrated to the new cells. Run two complete charge and discharge cycles without interruption. The BMS resets its reference points and the display returns to accurate reporting.