The adventures of living off grid

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The adventures of living off grid

Postby coachgeo » Sun Aug 03, 2008 8:04 am

Well last night was the first night.

3000/6000 cheap chinese 12v-120v invertor
two 12v marine batteries.

Results after about 8 hours:

batteries did not make it thru the night running:

. fridge listed at 307 Amphours per year (yea its small)
. Ceiling fan on high (where in a tripple digit heat wave. Nice at night with fan on here in my little slice of woods though).

Im at my office right now. Heading back out there with my computer Cellular internet hook up, some things out of storage etc. Will finish fixing generator fuel lines, service it and crank it up to charge batteries (6000w Yanmar)

have a bank of sixteen 66amp hour AGM 12v marine batteries to be shipped to me soon. Purchase price under a grand. shipping price.... Im afraid to find out.
Life; It's all in the Balance

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Postby coachgeo » Mon Aug 04, 2008 12:17 pm

Well got the ol Yanmar genset up and running good.

anyone know of a calculator I can use to determine how long to charge bank(s) of batteries?

Sunwizard, or anyone... Got a suggestion on a battery bank Monitor?
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Postby coachgeo » Mon Aug 04, 2008 2:09 pm

coachgeo wrote:...anyone know of a calculator I can use to determine how long to charge bank(s) of batteries?...
I came across this. Anyone know if their is any validity behind it?

unknown wrote:I charge 1 hour for every 10% of charge used.


came across this too

This chart is designed to be used when monitoring a battery under load. This chart is a little more useful to the average RVer, as we are most interested in monitoring the state of charge of our battery bank while it is actually in use


Image
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Postby SunWizard » Mon Aug 04, 2008 9:20 pm

Time to charge depends completely on the amp hours of your batteries, divided by the amps of your charger. Easy to calculate.

Voltage is only valid when at rest for >15 minutes, no load and no charging.
12.7 = 100%
12.1 = 50%
For lead acid.

Under load, the volts when 100% charged can drop a lot <12.6 depending on how many amp load.
YVORMV - Your veg. oil results may vary.
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Postby coachgeo » Tue Aug 05, 2008 8:37 am

battaries are 66 amp hour each. Well the new ones will be once they arrive. They are AGM. There will be 16 in the bank.

The charger is built into the inverter. It charges at 20amps / 13.8v
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Postby SunWizard » Tue Aug 05, 2008 9:27 am

coachgeo wrote:battaries are 66 amp hour each. Well the new ones will be once they arrive. They are AGM. There will be 16 in the bank.

Are they 12v or 6v?

If they are 12v, that would be 16*66 = 1056ah /2 since you normally only discharge halfway = 528ah /20a charger = 26.4 hours to charge. Longer if the charger tapers off the amps as they get full, like most do. I would get a bigger charger, my inverter charges at 120amps.

Half those numbers if they are 6v batteries.
YVORMV - Your veg. oil results may vary.
95 Dodge Cummins 4x4 SVO WVO conversion.
81 Mercedes 300D- stock and happy on V80/D20 blend.
Low fossil net zero house- 100% solar power and heat.
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