Re: NIMH charge early termination

Markus L wrote:
> 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.

Sounds like he's complaining that the fail-safe termination by 
temperature is his problem.
You can let it get hotter, charge it slower so it doesn't get so hot,
let it cool then restart.  No free lunch.
mike

--
Bunch of stuff For Sale and Wanted at the link below.
laptops and parts Test Equipment
Honda CB-125S
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/