Jim Dunmyer, thanks for your re-calculation. There is still hope. Cutting back a bit, to a 600watt A/cond running only 4 hours a day, and using some big deep cycle batteries,.......I could probably get by with 5 or 6 batteries. I would just love to see the look on the electrical patrol, when I get reported as using my Air Conditioner. When they come by and see that I am not plugged in, but instead running on DC current, they will walk away scratching their heads. How many AH will those big deep cycles produce? Bill Scott 61 Bambi, VAC & WBCCI #3221 1VP & Membership Chairman , WDCU http://www.servintfree.net/wbcci-dc/
Bill, That's actually pretty easy to calculate: Your A/C will draw about 9 amps, if I'm guessing correctly. That's at 120 VAC, so you'll be looking at 90 amps from the 12 volt battery bank. Add in a bit of inefficiency from the inverter, and let's round it off to 100 amps. You want to run the A/C for 8 hours, that's 800 AH total. As you shouldn't draw your batteries down more than 50%, you'll need at least 1600 AH of batteries. Golf cart batteries are approximately 200 AH, so you need 8 of them. You'd better figure on several more, "just in case". Your trickle charger and solar panels will supply 240 AH (charger at 24/7) plus about 30 AH from the panels. That's 270 AH against a load of 800 AH. I think the operative expression is "Pissing in the wind". Eight golf cart batteries will weigh about 500#, maybe more. They'll run your A/C for 2 or maybe 3 days before being pretty flat. That's if all my calculations are correct, it 'seems to me' that I'm missing something and I'm off by a factor of 100% or so. IE: 16 golf cart batteries would be more like it. Speaking of solar power: Has anyone noticed that the Diesel road signs are pretty much 'gone', having been replaced by solar-powered outfits? Those signs have 300 watts of panels and SIXTEEN golf cart batteries. The lights themselves are LEDs, not incandescent bulbs. That much solar power can give maybe 100 AH or a bit more on a sunny day. All of those batteries are to keep the thing going during a cloudy spell. <<Jim>> Bill Scott wrote: > > This is a design question for all you boondockers that would like to > have A/C without a noisy generator, or adequate 110 volt power. Anyone > with the savy can try to answer the question, and there might be a prize > for the winner. I fully expect Jim Dunmyer to have a competitive > design. Question: > > How many large golf cart type storage batteries will it require to run a > 9,000 btu Air conditioner, supplemented by a small trickle charger from > a low 110 volt source, putting into the batteries 10 amps of DC. The > batteries will also have a charging source of 2, 48 watt solar panels. > All of this DC current will then be fed into a 2500 watt invertor, to > provide the power to run the A/C. The Air Conditioner will only run > during the day, from 10am, until 6pm, a period when the solar panels > will be producing maximum out put. Ready, get > set,................................go. > > Bill Scott > 61 Bambi, VAC & WBCCI #3221 > 1VP & Membership Chairman , WDCU > http://www.servintfree.net/wbcci-dc/ -- <<http://www.oldengine.org/members/jdunmyer>> <<[EMAIL PROTECTED]>> <<lower SE Michigan, USA>> <<mailto:[EMAIL PROTECTED]>>
