How does MX4 charger detect different battery types?

XTAR Light

Apr 26, 2010
Smart chargers attempt to auto detect the battery type by the change of voltage. When you put the battery into the slots, the chargers will apply a small charging current (around 200mA) to the battery and observe the voltage. Due to different characteristics of the batteries, NiMH batteries will slightly boost the voltage under low current loading. As for healthy Li-ion batteries, the voltage will rise quickly. Then, the charger uses a short time to detect them again.

While, NiMH batteries and severely over-discharged Li-ion batteries may show overlapped voltage levels. It makes them challenging to be detected at first. Moreover, over-discharged high-capacity Li-ion batteries will require a longer time to be activated, around 5 to 10 minutes. To ensure accurate battery identification and avoid to identifying the over-discharged Li-ion batteries as NiMH ones, we set appropriate 10 minutes for detecting time on the MX4.

It's important to share that the extended detection time won't impede the charging process for NiMH batteries. Activation occurs together with charging, with a lower current. For those Li-ion batteries in good conditions, their internal cell voltages are between 2.5V and 4.2V. The charger will detect it and recognize it as Li-ion battery quickly.

MX4 LED indicators show different states: