What if I use a NI-MH charger to charge AA-Li batteries?

Your guys seems professional, hope any suggestion.

I have a lot of EBL AA lithium batteries and in order to charge them all at once. Some of these Li-ion batteries are charged with NI-MH battery chargers.

Now, some of these Li-ion batteries seem to drain fast, but some do not.

If this usually happens? Is there any way to fix the problem?

You probably should not charge Li-ion batteries with other chargers. I have not used Li-ion batteries, but I know Li-Po batteries use special chargers and cannot be used with other chargers.

PLEASE use a charger designed for the battery chemistry you are using.

NiCad and NiMH batteries often use what is called a peak charger (they charge until the voltage drops a TEENY bit, then the charger shuts off).

Lithium and lead batteries use a CC-CV charger (they limit the current until it hits a certain voltage, then limit the voltage until the current drops below a certain limit).

Just be aware that different types of batteries have different key voltages.

Wet cell lead batteries (like car batteries) need a different voltage than AGM (absorbed glass mat) batteries - commonly used in UPS units.

Lithium ion and lithium polymer batteries need a different voltage than LiFePO4 batteries.

TL;DR version: unless you REALLY know what you are doing, use a charger designed for the type of battery you are charging.

The results can range from minor (not fully charged batteries) to annoying (batteries that don’t work any more) to catastrophic (some types of lithium batteries can burst into flames if you severely overcharge them). Using the proper charger avoids any of this grief.