Re: [VAC] Air Cond for Dreamers

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

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are pretty much 'gone', having been replaced by solar-powered outfits?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>>