[A/S] Re: AGM's and cost

["Maurice Riggins <maurice.riggins@xxxxxxxxxxxxxxxx>" <maurice.riggins@xxxxxxxxxxxxxxxx>]

If you install two 55AH batteries, you might start with 100% of that 
capacity the first day, but about the most you'll get them back to 
with a few hours of solar, generator, or vehicle alternator is 90%.  
If you want to keep them above 50% charge, you only have 40% of that 
110AH or 44AH/day to work with.

If we assume running a generator from 6PM to 10PM every evening 
during lights, vent fans, water pump, hot water heater, 
TV/antenna/sat receiver, etc usage (about 25AH w/o TV, 35AH w/2 
hours), while charging the batteries, we only have to deal with about 
20 hours of electrical power for other things.

I haven't measured it, but the LP detector and refrigerator circuit 
board probably draw about 250 mA so that's about 10AH over 20 hours.

The refrigerator gas solenoid should draw about an amp when the flame 
is on, so if that's 50% of the time, we have another 10AH over 20 
hours.

If we don't run the water heater during that 20 hours, we don't have 
to worry about it's 1A gas solenoid.

If it's a little warm during the day only, and you can get by with 
the Fantastic Vent on low for about 2A over 12 hours/day, that's 24AH 
and there's your 44AH.

If it's little cool during the night and early morning hours, and the 
7.5A furnace runs a 25% of the time for 12 hours, that's 22.5AH and 
you're pretty close to your 44AH.

So 55AH AGMs might be doable if we ran a generator daily, and didn't 
boondock when it was too warm or cool.  I wouldn't want those 
limitations.

Without the Fantastic Vent or furnace, about the minimum usage we 
could get by with would be 45AH/day with no TV, radio, etc.  Even 
starting with a pair of 115AH Trojan Group 27 12V batteries at 100% 
charge (230AH), 3 days usage with no generator would take them down 
to about 40% charge.

If we want to boondock in warmer or cooler weather, or not have to be 
so frugal, I'd rather have 115AH batteries AND the daily generator 
usage with the AC voltage luxuries.

--
Maurice
WBCCI 5446