Well, let's see:
72 amp/hour battery
Loads: 4 small area lights, usually used one or two at a time, max of 3 hours a night usually. Water pump for the sink - maybe a minute a day. Once a week we run the computer for a couple of hours to watch a DVD. Sometimes I run the HF radio for a couple of hours of very casual operation. I might recharge my Ipod.
I figure that if I put 50 watts on the roof, flat, I'll average 25 watts, so that's about 1.5 amps.
The radio draws about 600 mills on receive, and with my usual duty ratio, I probably transmit 6 to 12 minutes per hour so I need maybe 7 amp/hours for an average couple of hours.
Since my trailer battery also recharges from the car when I'm towing it, I figure with 50 watts I can dispense with my the extra 33 amp/hour gel-cell that I have carried to run my radio on most of our trips.
That's 25 lb's, and a charger, plus space saved in the towcar.
At a cost of almost $400 even at Harbor Freight. I must be out of my mind.
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