I am aware of most of the thinsg to be aware of 8*) but I am just
     hunting to compare notes with other people that have implemented their
     own battery chargers. With regards to the charge type, I actually use
     a rate of change of temperature for terminating the fast charging of a
     550mAh NI-MH battery. And this appears to work just great and
     terminates at pretty close, to within 30 seconds, where a peak voltage
     (dV/dt < 0) method would terminate. This has been measured by
     attaching a GPIB voltmeter to the battery as it is charged and then
     plotting the data in Excel.

     If the battery has been charged to the point where the 'voltage peaks'
     then how much capacity should I be able to get out of the battery? FYI
     this is charging at a rate of 1C.

     thanks in advance
     SW.


______________________________ Reply Separator _________________________________
Subject: Re: Re[2]: selection of battery for power consumption of 300
Author:  pic microcontroller discussion list <PICLIST@MITVMA.MIT.EDU> at
INTERNET
Date:    09/06/98 08:45


>     And we are discharging Ni-MH batteries down to 1.1V per cell, and seem
>     to be getting aound 80% capacity out of the cell when discharging at
>     1C ... does that sound reasonable?

A lot of other factors come into play, including temperature, charge type
(peak, timed, etc.)

You should get 80%-90% out of what you put in, as a rule of thumb.  I put
2200-2300 mAH into a 2000 mAH cell, and get about 1980 out.

Andy

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Andy Kunz - Statistical Research, Inc. - Westfield, New Jersey USA
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