"PeteS" wrote:

Li+ / LiPoly batteries should be charged in a constant current/constant
voltage scheme.

At initial charge, a constant current should be used, until the cell
reaches 4.2V. At this point, the charger should charge at constant
voltage until a threshold current is reached.

The current to charge with varies with battery. The C rate is usually
good. If the battery is 4.1Wh, then it's about 1Ah. 1A constant
current until 4.2V, and charge cutoff at 100mA would be a decent
solution.

It is very important to *not* let the cell be charged above 4.2V,
unless you want some interesting pyrotechnics.

See the http://focus.ti.com/docs/prod/folder...t/bq24103.html
BQ24103 and related devices at TI for an excellent explanation of the
charge cycle.

Cheers

Thanks, Pete, just what I needed.

If I fail to access the case innards (or fail to fix it anyway), I'll
try that. Without a new design to incorporate a very sensitive voltage
comparator, I suppose in practice that means setting it to say 5V, 1A
initially and watching my DMM closely?

--
Terry Pinnell
Hobbyist, West Sussex, UK