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ronb avatar image
ronb asked

Plunging Voltage

With my MPPT 100/50, after a year of no problems, I'm experiencing battery voltage dropping to almost just 10 volts, causing my invertor to kick off. Haven't changed my usage patterns or increased loads. These drops occur mostly but not always after the solar ends as the sun sets. The battery SOC is always above 60% but below 70%. I have 3 100 Ah Lipo batteries. My battery voltage and solar power charts are attached. Any ideas?05141.jpg05142.png

voltage drop
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1 Answer
Alistair Warburton avatar image
Alistair Warburton answered ·

That just looks wrong... However without knowing what the batteries are that bust a guess Do you mean LiPo or LiFePo4... Not the sane thing at all

I am guessing but it looks like the charge profile is wrong or the failing.

I say that because the voltage comes up way to fast in Bulk and then drops to Absorb/Float, whatever which is either set to a voltage that is far to low or is correct for your cells, that are bad.

The net result is that most of the day the batteries are just sitting idle, are not accepting charge.

I cant comment of settings without more info, sorry. Check out the links for details.

https://batteryuniversity.com/articles :- The ones you need, to start with, are below

LiPo vs Li-ion LiFePo4 Charging Li-ion Charging

Hope that helps

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