18650 can't charge fully?? Help pls

[DOCG]

Hey, I have LG HG2 20A batteries and when I charge them it is okay but when it is almost full it the charger gets stuck at 90% though it says that voltage is 4.2. I thought I just need to wait, but I waited for 15min or so and still the charger was stuck at 90%. But the interesting part it showed that it was still charging, I mean the mAh's was slowly increasing but percentage stuck at 90%..

The charger is new. What should I do?

 

[score69]

What kind of charger, make and model?

The charger will analyze the remaining charge as the batteries charge. It looks at the current voltage and estimates how many more mAhs it needs to finish charging, but it doesn't really know the full capacity of the battery. This is an ongoing estimate.

How long does it stay at 90%?

 

[Baditude]

All that info and you failed to say what charger you are using.

Most modern chargers today use a charging algorhythm.

A charge cycle involves two main stages; constant current or CC, and voltage source or CV, but some chargers skip or add more stages.

Charging process:
Stage 1 – Automatic analyzing battery status
Stage 2 – Quick charge
Stage 3 – Slow charge
Stage 4 – Standby mode, trickle charge​

If the battery is reading 4.2 volts, then you can consider it to be fully charged and you can use it in your mod. I'm not sure what your charger is doing once the battery shows 4.2 volts because I don't know what algorhythm its using.

 

[stols001]

Hard to say without knowing your charger, there. It sounds like they are fully charged if hitting 4.2 but it's very hard to say what is going on. It could be your charger wants to do another cycle or two or something, it may be that 90% is "full" to your charger, but honestly without knowing more I might say stop using the charger until you get it figured out, you neither want to overcharge or overstress your battery and if there is something wrong with the charger and it's continuing to charge when it shouldn't I can't imagine that would be good for your batteries.

Please provide more information.

Anna

 

[Mr. Relentless]

Mine stays at 4.19 for a half hour before hitting 4.20. Right when it hits 4.19 it's actually only at 80 85%. Ive seen alot of chargers where that last 10% takes longer then anything prior. I believe either the display readings are mapped wrong or it starts trickle charging towards the end.