Anotherpower.com Forum
Renewable Energy Questions/Discussion => Renewable Energy Q&A => Topic started by: WooferHound on February 21, 2012, 10:29:58 pm
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Your Battery Bank Size, adjusted to 12 volts ?
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i've got 8 trojan (6v) T-125s not 105's. i think they're 240Ah each? in a 24V system gives me 480Ah.
i think i did the math on a 50% discharge (worst case situation) and found i could pull 3Kw from it without ill effects.
adam
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If you have a 24 volt system you would multiply the individual battery capacity times 2 to scale it to a 12 volt system
for 36 volts you would multiply by 3
and a 48 volt system would have the battery capacity multiplied by 4 to adjust to 12 volts
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i've got 8 trojan (6v) T-125s not 105's. i think they're 240Ah each? in a 24V system gives me 480Ah.
i think i did the math on a 50% discharge (worst case situation) and found i could pull 3Kw from it without ill effects.
I find it much better to work in "watt-hours" of capacity. Takes all the system voltages out of the equation.
240AH * 6V = 1440 watt-hours per battery. Regardless of how you connect them - all series, all parallel, series-parallel, you have 8 of them @ 1440 watt-hours each = 11,520 watt-hours total.
At 50% depth of discharge (I think that's far too high, by the way) - you have 5760 watt-hours of "usable" capacity, or 5.76 kWh.
(Please note the extra 'h' in there. "3kw" is a meaningless figure in the context of battery capacity)
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ross,
yes, i forgot the extra "h". i try to baby my batteries, and only pull 3Kw "h" from them. so that's be less than 50% discharge.
so as per the 12v rating i'd have 960Ah of battery??
adam