> I could find from Digikey. My Vin is coming from a 20Vac 800ma
> wall wart, going through a full bridge rectifier. I am able to
> control the charging current OK with the PWM from my PIC.
> The charger has 3 modes full 1000ma, soft 375ma,
> and trickle 75ma.  The problem is on my first full test,
> the wall wart got very hot after about 35 minutes of
> FULL charging.  Can someone enlighten me as to why it is heating
> up ?

It's hard to say for sure not really knowing what "very hot" means (was the
plastic dripping off?) but since your system isn't 100% efficient I'm
suspecting an 800mA wall wart might be having trouble delivering 1A of
current at whatever voltage is needed to keep 1A going through the battery
pack. at different times during the charge cycle. As the cells are charged
a higher and higher voltage is required if you are truly maintaining a
constant current through the pack.

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