MPPT power using up power

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dougkimmerly asked Mar 13, '23

MPPT power using up power

I have 4 MPPT150/70 devices two of them seem to consume all the power that they generate. Where I see that is in the DC Power used. Our "normal" DC power usage is about 200 -300w, as the sun gets more powerful and the chargers generate more our DC Power goes up to 800-900w. If I turn off the breaker connecting the solar MPPT to the battery it drops back down to 200-300w. This only happens with two of the controllers the other two don't seem to be using up the power. I have no idea what is actually happening here, any suggestions?? There is nothing connected to the loads, and I even have the loads turned off always.

MPPT SmartSolar

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dougkimmerly answered · Mar 14, 2023 at 02:42 PM

Solved now. The two controllers in question were wired up to the batteries directly bypassing the shunt, also affecting the voltage difference the shunt uses to determine current. So the controllers were not "using" power but the shunt detected a power usage that was not there.

Switched the negative leads from the controllers to the other side of the shunt and everything is recording just fine now.

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Modifications Space

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Answer 1 · 2023-03-13T15:27:13Z

dougkimmerly answered · Mar 13, 2023 at 03:27 PM

In these three screen shots you can see that as input power increases the power usage increases. Then when I disconnect the two MPPT's power usage drops back to normal. I am netting out more power by disconnecting the controllers.

1749w.png (208.8 KiB)

1824w.png (209.3 KiB)

diconected.png (203.5 KiB)

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