Everyone,
paulcheung is partially correct. I don't have a faulty volt meter, I am a faulty volt-meter-reader I think. I have an analog meter and after his comment, I just now went and tried it again. I think I had read the wrong scale. I re-measured and they were all reading at about 6V and the total battery bank was at about 51V. My apologies to everyone, and yet again, I feel pretty stupid. I double checked the volt meter on my newish truck battery and it read 12V. So, I think the volt meter is OK. You all can tell me if you think that changes the theme that has emerged that the batteries are or may be bad. I won't have a hydrometer for another week, so I can't do any other kind of testing until then.
In the meantime, I was getting ready to post these thoughts about the discussion to date.
Thanks again for the advice/suggestions. I've learned quite a bit in two days! I didn’t mind hearing any of the things you had to say at all, but my wallet groaned heavily when I priced the batteries Sunking had recommended!
Following Sunking’s calculations and patient explanations, I just wanted to break it down in a bit of a real world way now to see if I really get it, which will help me figure out how to proceed. Based on what you said, I went back and re-calculated what we actually use up here by testing everything we have plugged in and use regularly, i.e, measuring actual draws, and I was able to come up with a daily usage of about 6,000 watts, or 180 Kwh/mo.
So, in an ideal world, and if I had maintained my batteries properly from the start, the maximum amount of power we would want to use on any given day is 5.3Kwh, which is 30% of the 17.76 Kwh that my 6, 8V batteries can “store” at 100% SOC (6 batteries X 8 Volts per battery X 370AH per battery = 48 X 370 = 17,760 watts or 17.76 Kwh). Based on my usage, however, it seems that I’m using 6Kwh day, or 35% a day, on average. Correct?
I see where a 370Ah rated battery isn’t quite big enough to allow for a 70% SOC, and certainly wouldn’t allow for any real storage for those cloudy days. In theory, if we reduced our usage to 3.5 – 5.3 Kwh, couldn’t we get away with the same size battery we currently have if we maintain it properly. Conversely, if we want to maintain our “extravagant” lifestyle of 6Kwh, then we would need at least a 420Ah rated battery, as suggested.
I just now saw that you posted hoping I’d get back to you soon, so here it is.
Dan
paulcheung is partially correct. I don't have a faulty volt meter, I am a faulty volt-meter-reader I think. I have an analog meter and after his comment, I just now went and tried it again. I think I had read the wrong scale. I re-measured and they were all reading at about 6V and the total battery bank was at about 51V. My apologies to everyone, and yet again, I feel pretty stupid. I double checked the volt meter on my newish truck battery and it read 12V. So, I think the volt meter is OK. You all can tell me if you think that changes the theme that has emerged that the batteries are or may be bad. I won't have a hydrometer for another week, so I can't do any other kind of testing until then.
In the meantime, I was getting ready to post these thoughts about the discussion to date.
Thanks again for the advice/suggestions. I've learned quite a bit in two days! I didn’t mind hearing any of the things you had to say at all, but my wallet groaned heavily when I priced the batteries Sunking had recommended!
Following Sunking’s calculations and patient explanations, I just wanted to break it down in a bit of a real world way now to see if I really get it, which will help me figure out how to proceed. Based on what you said, I went back and re-calculated what we actually use up here by testing everything we have plugged in and use regularly, i.e, measuring actual draws, and I was able to come up with a daily usage of about 6,000 watts, or 180 Kwh/mo.
So, in an ideal world, and if I had maintained my batteries properly from the start, the maximum amount of power we would want to use on any given day is 5.3Kwh, which is 30% of the 17.76 Kwh that my 6, 8V batteries can “store” at 100% SOC (6 batteries X 8 Volts per battery X 370AH per battery = 48 X 370 = 17,760 watts or 17.76 Kwh). Based on my usage, however, it seems that I’m using 6Kwh day, or 35% a day, on average. Correct?
I see where a 370Ah rated battery isn’t quite big enough to allow for a 70% SOC, and certainly wouldn’t allow for any real storage for those cloudy days. In theory, if we reduced our usage to 3.5 – 5.3 Kwh, couldn’t we get away with the same size battery we currently have if we maintain it properly. Conversely, if we want to maintain our “extravagant” lifestyle of 6Kwh, then we would need at least a 420Ah rated battery, as suggested.
I just now saw that you posted hoping I’d get back to you soon, so here it is.
Dan
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