Parasitic drain

I recently lost two Efest 3,400mAh batteries that had protection installed on the cell. When I examined a flashlight recently that wasn’t working properly, I always check the batteries and these two cell were dead! No voltage! Two cells did this apparently at the same time, but the other cells in that light are fine. I’m scratching my head as to what happened? These were not cheap cells, but I haven’t used the flashlight recently.

My mind tells me that two cells couldn’t go bad simultaneously. I wonder about the protection circuity. Are these circuits live all the time, meaning they have a tiny parasitic drain on the cells even if those cells are not in use? Could this overtime, drain the cells to a point where they become non-functional? For the battery expects out there, can this happen?

Cheers,

Eric K

The battteries will read completely dead if the protection circuits on them tripped.

Maybe put them in the charger briefly and then test voltage to see if you can reset the circuits.

+1

I agree with advice above. If your charger can’t reset the circuit there is another way to reset them.

I’ve noticed my laptop pulls (unprotected 18650) hardly lose any voltage month to month. Protected batteries however tend to lose 0.1-0.2 volt every week or so. For this reason I check mine at least once every ten days.

To reset a batteries protection you need to hook it up to a good (non-tripped) cell. Only do this for about a second.

I saved this a while back. I can’t remember if it was from HKJ or Scaru.

The $6.00 Xtar MC1 can reset those batteries as well

That’s good to know, I bought one a while back. Comes in handy.