Model Forum / Radio Controlled / Land Models / January 2005

You'll need a constant-current supply capable of at least 13.0 V, and
pushing out no more than C/2 (that's the capacity of the cells, in Ah,
divided by 2 - so if they're 800 mAh, you need a 400 mA supply *or
lower*).

I have a Nikko 'wall-wart' which was sold specifically as a 5-hour
charger for 8 AA ni-cads, and plugs directly into that socket on the Tx:
it states "10 V  150 mA" on the casing, but I've watched it peak the
cells at 12.8 V so it's clearly lying on at least one front!

Particularly if your supply is above 150 mA or so, you'll need to be
careful not to over-charge.  Ideally it should be a proper peak-detect
charger unit; but you can stop when the cells feel nicely warm (not hot;
about 35°C will do) to the touch, or you can do what I do and watch the
voltage with a digital meter - when it's reached a peak and fallen back
by about 0.05 - 0.10 V, they're charged.

With a supply of, say, 100 mA or less, you can probably just charge them
overnight in safety (divide the capacity by the charge current to get
the time hours, then add about 20% to ensure a full charge).

Hope that wasn't too long-winded, and hope it helps!
Jonny