Warm battery pack

[Chief31]

So I extended my 8.4v 4 x 18650 batteries to 8 batteries. Three of them. 2 packs are fine but one pack has started to feel warm. As to say warm just the other packs seem stone cold and one doesn't. Any ideas?

 

[uk_caver]

Under what conditions does it get warm?

Does it have protection circuitry (and if so, is that rated for a larger pack)?

 

[Chief31]

Under charging the pack Luke warm.
One pack stays stone cold but the other seems like room temp.

 

[SilverFox]

Hello Chief31,

While warm is basically OK, I would keep an eye on that pack. If possible replace it and break it down to single cells. It is telling you something is a bit off and you should listen.

Tom