stylinsty

I am considering using an ac wall transformer that puts out 200mah and 9v to charge a 7 cell 300mah nimh battery and also a 7 cell 170mah nimh battery pack.

Will it work?
If it can how is the polarity to be wired up for charging?

Thanks,
Steve

jimbosstuff1

Hi Steve, yes a wall charger is a transformer of sorts,primary and secondary windings,with a diode and a resistor(most of the time) that covert 110ac to different lower voltages ac or dc."step down transformers" Useally on the back or the side of the plug-in-charger their's some info..Like 110ac-9vdc@500mah. Its a good idea to have a volt meter to deterimene the neg. and pos.wire end of the adpt. In order to install the type of connector you need to match your packs connector. But do yourself a favor and spring for a store bought charger thats designed just for what you want to do. There's bounches of them, and in good price ranges that can fit any pocket book. If your going to play with electrics its a must have. Backyard Flyer,Fly R/C,Quiet Flyer,MicroFlight are all good sorces of the kind of information that will help. The forum your in now is great. You can have questions ,and get answers,cool.

stylinsty

So a wall transformer can't be used to charge batteries because it does not have a diode- without the diode electricity can go the wrong way and it doesn't work /causes fires?

I bought a car lighter charger for $20 at hobbytown.
It has peak detection and a knob to charge from .3 to 1 or 2! Good deal.

Thanks,
Steve