Am i to discharge my 7.2 nicad or nihm battery and if so how far do i discharge

I'm sure you'll get a more informed answer soon, but as far as I know, there's no concern with low voltage in NiCds and NiMh like there is with Lipo and LiIon. NiCds should be discharged to avoid battery memory as opposed to NiMh which aren't prone to that.

I just ordered a Onyx Advanced charger to join the real world. I've been making due with 1800-2000 NiCds and my old Hobbico charger for the past years with my Tamiyas, but it's time to get into the larger 4200-5000 NiMhs with the StuG. The extra electronics eat up the smaller batteries.

On the old charger I would run the pack until the tank was dead, then further discharge to zero amps on the charger's analog meter. I have old Piranna packs that are over 10 years old and still work fine, so I guess I was doing the right thing.

I'm starting with 2s lipos soon for my Xion Kettenkrad, hence the leap for the better charger. Now I'll really have to pay attention.

nicad should be discharged every time as low as you can left to cool then charged again. {thats why a lot dont get them} ni hm dont need to be but some do it once every so many charges to keep cells balanced