"VanguardLH" wrote in message
...
john d hamilton wrote:

I have a few 9v Ni-MH batteries 200mAh.

I have two chargers one with output at 9v of 10ma and the other a very
old
one that says output is 7.2v (even though its designed to take two 9v
batteries) and whose output says it is 15ma x2.

Which would be the best to use on the 9v Ni-MH and what would be roughly
be
the minimum charge time to ensure batteries are fully charged please?
thanks for advice.

The one that is designed to recharge NiMH batteries. The charger needs
to cease charging NiMH batteries when they reach full charge and then
not charge thereafter (i.e., no trickle charge to top-off the battery).

Not so.


If a thermistor is not used to detect a full charge then a timer should
be built into the recharger to ensure the charger turns off (to no
longer continually try charging the battery).

A thermistor cannot detect full charge. It can only detect the temperature
rise near the full-charge point. This is not quite the same thing.


NiMH should be charged at a very low rate.

This is simply untrue. I work at Microsoft Hardware, and have been learning
about the differences between NiMH and nicad charging.

NiMH cells will tolerate very high charge rates. Indeed, the high rate is
desirable not only for convenience, but because it produces are large
voltage _drop_ at the end of charge. The better chargers can detect this,
and shut off.

In general, any charger that will handle nicads will also charge NiMH cells
safely.