nimhs question
 

how many amps would 12 nimhs in series put off at 3800mah

That depends on the cells and what their discharge C rating is. I had a couple of tenergy 4500mah 6 cell packs that had a 40C discharge rating 4500/100= 4.5x40=180Amp discharge. However this would be really pushing the cells and they probably wouldn't have lasted long. I was hitting about 100amp peaks with them and that was heating them up pretty good. To give a general rating on your cells, they're probably capable of about 70 amps continuous, but don't take my word for it. I would wait for someone with some more knowledge or until you find out what cells you have and what they're discharge rating is cause without that all we can do is speculate.

In addition to above, it will depend on what voltage you can tolerate. If you need 1.2 volts the current isn't going to be very high unless you use best cells, if you can tolerate less than 1 volt/cell then the current can be far higher and you can get away with cheapo cells.

I will have to say that 40-50 amps wil be about it. Much more and they will run very hot, and the voltage drop will be extreme.