I'm trying to charge rechargeable AA batteries with a solar panel. What gauge wire should I use to connect the panel to the batteries? I know I'm not going to have a lot of current going through so the wire size doesn't really matter. Can the wire be too thick thoShould I ugh? Should I use a diode to keep the batteries from overpowering the circuit? If so, what size diode? My panel is 4.8V 50mA. Can I just hook the panel straight into the batteries or do I need something else?
In order: .? Just about any wire will do.? You can handle 50 mA over just about anything, even 28 gauge telephone wire.? Your biggest problems are probably going to be mechanical stress (you want stranded wire instead of solid, to avoid breakage) and dealing with the size of larger wires. 8 gauge speaker wire may be a good optimum. 2.? You need a diode.? If you're charging NiMH or NiCd cells you're going to have about .25 volts/cell; you can charge up to 3 of them in series with a 4.8 volt panel.? The solar panel is a bunch of diodes itself, but they're leaky in the reverse direction; the diode prevents the batteries from discharging themselves back through the panel.? You want a Schottky-barrier diode, because the forward voltage drop is about 0.2 volts instead of 0.7 volts for a regular silicon rectifier.? This gives you maximum current output from your panel.
