question

jhayes avatar image
jhayes asked

Battery voltage is display float charge

Product: SmartSolar 100/30: The issue that I'm having is the battery voltage is displaying the float charge instead of the actual battery charge. For example, right now, the battery voltage reading is 13.22v but the actual battery terminals read 12.5v.

MPPT Controllers
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2 Answers
wkirby avatar image
wkirby answered ·

The most likely cause is a high impedance path to the battery. There is probably a bad connection somewhere between the MPPT and the battery it's self.
If there is a poor (high impedance) connection somewhere then the MPPT finds it very easy to reach its target Voltages which it measures at its own battery terminals.

3 comments
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lklmenterprises avatar image lklmenterprises commented ·

Best way to check that quickly would be remove the Battery you are trying to charge and see if that voltage on the MPPT changes. If, as WKirby stated it is Extremely high impedance (open circuit) - nothing will change. If it is High but becomes Higher when you remove the battery, wherein it becomes Open circuit, the voltage will likely change, but also the MPPT should stop functioning as they use the Battery side to power their own electronics, not the PV side, so I believe subsequently the voltage would drop to zero.

But considering you appear to have a fairly complex wiring diagram (which is great to see by the way!) it could also possibly indicate another battery source...such as Starter battery, or another DC voltage source - which by itself will have a completely different impedence to a Battery unit.

Be sure to check here that nothing is acting as a Bus bar and not individually fused as I think it is supposed to indicate, also because to me that symbol looks almost more like it could be a Bus bar...

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1594048337680.png (27.7 KiB)
jhayes avatar image jhayes lklmenterprises commented ·

The image in question.

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busbar.jpg (745.8 KiB)
jhayes avatar image jhayes lklmenterprises commented ·

You stated "Higher when you remove the battery, wherein it becomes Open circuit, the voltage will likely change, but also the MPPT should stop functioning as they use the Battery side to power their own electronics, not the PV side, so I believe subsequently the voltage would drop to zero." Does this mean that the smart solar will operate when the sun is down? My unit will not work in the evening, no communication. with the device. It only turns on when the sun is up.

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jhayes avatar image
jhayes answered ·

Back in the solar game. Thanks everyone for helping me out. Error on my part when I replaced the blown fuse (top bus bar far left terminal) I didn’t set it in correctly, at an downward angle and the push up at the top. I had re-seated that thing numerous times.
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