I was looking at Cabellas SunForce 12 Volt 5 Watt for 60 bucks
Where did you purchase yours?
I thought I would pick one up to keep my Batteries on my RV Trailer and Electric Trollen motor for my Pram Charged while Vacationing.

I believe that you will be taking a pillow to the gun fight with that unit!

The formula is watts/volts=amps:

so: 5/12 = .42 (hope I got that right)

You might be able to maintain a fully charged battery in storage with that unit but the recharge rate would seem to be waaaay too slow for your application.

I finally broke down and purchased a Honda 3000 to run the A/C on my travel trailer as well as to charge boat batteries using a high rate charger. That generator will provide juice for the frig/freezer at home in event of power outage and the power generated is "good quality" for computers. Also, it is very quiet and fuel efficient. I also looked at the Yamaha units - it was a price and local service choice for me.

I will add that two years ago on an extended pronghorn hunt to Wyoming we had a generator to recharge batteries and also to run the freezer we brought with us for meat. It was an inexpensive unit and while it did the job it was very noisy to the point we had to build a sound barrier.

Yep,you'll need way more than that. My aunt and uncle live in Ephrata (loads of sun). They've got a couple grand worth of solar panels on the roof of their motorhome. Even with all the panels,they still have to use their generator at least an hour per day to keep the batteries topped off.