6S LiPo advice - Bad cell

[duc996bp]

So far all the batteries I have ever bought have been good from the start, however just received today a new Gens Ace 6S 45c 4400, all cells were howing 3.8v except for cell 2 at 1.9v.

I.R for all the cells are about the same 2.5 mohm

Would you reject this from the go or try and and charge it?

[CharlieK]

Verify the reading. Complain to the vendor. Do not accept a Lipo with a cell that is below ~3.75v or that has significant differences in cell voltages, usually below 3.8v for the lowest cell.
It's worth remembering that getting an accurate reading within .01v is not always easy. As a result, most readings made are usable because they are "relative".
When I really need an accurate reading, a 6-1/2 digit .003% lab DMM is used. It even has a plug in accessory scanner that can be used to measure multiple cells in quick succession while the battery is being charged or discharged. Measuring higher current accurately would require use of an external temperature compensated shunt that I don't have.

[duc996bp]

Thanks

I did ring the shop, they agreed to send me a new one without any fuss.

This is the first time I have had a battery from new like this, with one cell well below the normal storage voltage. Wasn't sure if this sometimes happens and the normal pratice was to charge/discharge it say 4 or 5 times, then all will be ok.

[Smoggie]

If a cell was as low as 1.9V then you wont be able to charge it. The charger would see it as a bad vcell and give you an error.

[duc996bp]

That is a very good point and was expecting that. I have a PL8, it clearly showed the cell 2 at 1.9v at the start AND did allow me to start charging. Eventaully after about 2 hours the cell did get upto 3.8v with the other 5 on constant 99% bypass. It was at that point I decided do I really want to risk my heli with this!

[EjectEjectEject]

I think many will allow it to charge, but only at a very low rate until it gets above 3.0 volts for that cell.