When a 18650 Li-ion battery got FULLY charged...

XTAR Light

Apr 26, 2010
A customer told he charged one 18650 battery in his PB2S up to 100%, then put the battery into the VP4 PLUS, while found it showed 91%. It seemed his charger displayed inaccurately, or it's just because the battery didn't got fully charged. If you have the same question, please don't remove the battery from the charger, until you see "FULL" on the screen. That means the battery has been fully charged properly.

We know it adopts the three-stage strategy for charging Li-ion batteries: TC wake-up precharge, CC fast-charge and CV fully charge. In the constant voltage charging stage, the current will gradually decrease. After it drops to a certain extent (usually C/10), the battery gets fully charged and the charging process will be cut off. The saturation charge will take some time accordingly to ensure the full charge.

For the percentages of the charged volume on the chargers, the data is based on the voltage. When you see 100% on the screen, the battery may still under charging. It will get fully charged once you see "FULL". Just leave the battery in the slot and let it charge properly.