3na consumes the total charge in each of her two batteries each night! She has over 100' of coolneon in her, but she also uses five separate inverters, which consume nearly an amp! So the 7 Amp-hour battery lasts about 7 hours.

Her color guns don't last even that long!

She'd eat a dozen D batteries per night or more if I'd have gone the disposable route. Since she uses large capacity rechargable batteries all I needed was a charger, and since there is plenty of sunlight in the desert a solar charger made sense.

I found a good deal on solar cells on the internet and built one panel for charging the 12V battery and one for the 6V battery. I found a circuit design for a gel-cell battery charger which reduces the charge to a trickle when the battery is fully charged.

Soldering solar cells is much harder than it seems. I had to use 4% silver solder and a fairly powerful soldering iron. Ultimately, the trick turned out to be to scratch the surface to be soldered with an X-acto knife.