I have a J3 Cub with a C85-12. I love the plane for my mission (floats, skis') but hate rechargable batteries to run my GPS and intercom. I do not want a starter or battery because of the weight, but do I have any options for an electrical generator off my engine? How much and where can I find someone who has done it?
Thanks

This isn't what you are asking but have you considered one battery to run everything? Goal Zero makes power packs of every size. Buy one, plug everything into it, only one thing to charge when you get home.

http://www.goalzero.com/shop/c/2/

What about a RAT (or whatever they're called for light aircraft). I know of a Cub that has one mounted on the gear to power a radio, intercom, and (I think) GPS. Obviously no power when you aren't moving, but that's what the batteries are for. Once you get flying the airflow generates enough power to run (and I would think recharge) the few electrical loads it powers. The same system can be found on older ag planes to run their pumps/whatever.

A 10 to 20 watt PV panel would keep your battery up, how to mount it safely, don't know. You can get thin flexible PV panels that would conform to the top of the fuselage and be zero drag, for Cub speeds anyway. That'd be lighter and cheaper, less drag too, then a wind turbine type thingie.

Thanks fellas.

I will look into those.

B&C makes an extremely small & light alternator that fits the -12 Continental engines. But how about a stand-alone small sealed type battery with GPS/com/ intercom hardwired to it? Mount a battery-minder connector on it & charge it up in the hangar as required. A friend of mine has had a set-up like this on several airplanes using what he calls a "modeller's battery" and only had to charge the battery once or twice a month. You could even install a transponder & have mode C capabilities if desirable for your normal flying, without the hassle of mounting any sort of generator.