Re: NIMH charge early termination

Dave VanHorn wrote:
> 2100Mah Cells, in a six-pack, being charged at C.
> Mfgr says to terminate high rate, at 40C.
>
> The pack runs up from 28C to 40C in 26 mins, with voltage slope still
> rising, indicating to me that it's nowhere near full charge....
>
> Not sure what to do here,  I hate to push the mfgr's spec, but 40C
> seems to be unusually low.
> At this point, I've put about 30kJ into the battery, but full charge
> happens around 72kJ.

See the excellent text on fast charge termination techniques on pp. 16 ff.
of
http://www.linear-tech.com/pdf/an64f.pdf
It says that absolute temp cutoff (TCO) is too susceptible to variations in
ambient temperature conditions to make a good primary cutoff technique.