Let my LIPO's run dead

so i forgot my batteries plugged in to the vesc and they ran dead now my charger refuses to charge them, i have 18.5v - 4000mah 15c lipos and my charger is a tenergy tb6b charger, any help?

Once you undercharded it, dont use it. It may be really dangerous to continue using it.

Most likely they are ruined and will never be the same nor do I imo think its a good idea to use them again on high amp draw applications. There is however a way to revive them so your charger will be able to charge them again. Youll have to charge them in NiMH/NiCad mode. It could be very dangerous and if you do go down that route make sure your outside just in case the lipo catches fire. Just google how to revive dead lipo.

It’s possible to fix usually all but one cell. You have to charge them very slow off a power supply or a nimh charger at the lowest amp you can. I’ve found that when this happens usually one cell is permanently ruined but the other cells can be revived.

think i can use the same charger to do the nimh trick?? and is it safe to keep using them???

@ecuadorche you can use your charger to do it, put it in ni-mh or ni-cd mode and charge the batteries at 0.1A until they reach 3v per cell. Then switch to li-po mode and charge as normal, your batteries should be fine its happened to me before, but the longer they sit flat for the more damaged they will be so charge them ASAP. Just be careful when charging in ni-cd or ni-mh mode it will keep charging the battery past its max voltage. I hope you get them going again.