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Leon Burgher avatar image
Leon Burgher asked

MPPT 75/15 Abrupt Change in Characteristics

img-8057.pngHi, Around three days ago my controller began dropping off in charge to the battery. Although the app tells me there was bulk, absorption and float, the yield has fallen away to next to nothing. Is this, as I suspect, a catastrophic battery failure? It also happens that I just upgraded to OS version 6.0 of the app. Help

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2 Answers
christern avatar image
christern answered ·

The low battery voltage looks like the batteries have seen their best days, so yes, most likely the batteries should be replaced.

Have the always been below 12V or is it something new?

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Leon Burgher avatar image Leon Burgher commented ·
Thanks Christern, Normal operation from Day 1 for this system has been a voltage range of 14.4 max to around 11.0 min, which is around where the inverter cuts out. We’ve recently experienced a short heat wave locally, with room fans left on overnight. I was getting corresponding high yields following that period. Then, within a couple of days, this. The three 12V batteries my micro system use are around 10 years old. Thanks again for your response. Happy to read any other opinions as I’m in the dark on this, literally!
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kevgermany avatar image kevgermany ♦♦ Leon Burgher commented ·
Running lead acid to such a low voltage is not good for them. If you're replacing with lead increase the capacity of your batteries so that you don't discharge below 50%.
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christern avatar image christern Leon Burgher commented ·
11,0 V is very low unless there is a fairly high load on the batteries. Without any load and with a rest of around 24h a lead-acid battery should never drop below 12,1 V. I agree with @kevgermany. You seem to have a load that is higher than your capacity and you should be happy that the batteries have lived as long as 10 years.
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Leon Burgher avatar image
Leon Burgher answered ·

img-8068.jpegHi Chris & Kev, I have now renewed my battery storage with 3 X units as per photo. Having looked up typical Deep Cycle performance characteristics I now understand what 50% capacity really means And yes, 10 years is probably a very good run, under the circumstances. I checked my installation date and it was actually 12 years ago! It seems my micro system is a little too-micro, so I’ll be investing in more panels in the next iteration. Thank you again for your advice and feedback. Cheers Leon



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kevgermany avatar image kevgermany ♦♦ commented ·
Hope it's working well now
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