Hey Al! How are ya? Good to see you on RCU!

Regarding batteries and charging. Alan is 100% correct. There is overhead when charging batteries, meaning you just can't put in 1000 milamps (1 amp) into a 1000 mah battery and expect it to be fully charged. There are resistance losses in the wire, and internal losses due to heat in the battery pack and charger, so, as Alan said, 140% to charge 100% is more realistic.

There should be some indication of the capacity of your batteries and some indication on your charger that says what the output current is. Do the simple math and add 20 to 40 percent to that and you will know how long it should take for a FULLY DISCHARGED pack to recharge to capacity. Partially discharged packs will not take as long. But, if this is a typical wall wart type trickle charger, then it won't matter if it stays on longer than your calculated time. If it is a fast charger, then closely monitor the charge rate and stop it when it is fully charged.

Many, if not most, of the fast chargers will switch to trickle after a full fast charge is completed, but some will not. You have to check to see what your charger is capable of.

I know.. I know.. you said transformer, but a transformer with a couple of diodes is all a wall wart charger is.

CGr.