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donnyv avatar image
donnyv asked

MPPT and Battery AMPs different value clarification

Hi,


I have a full Victron setup with networking enabled between everything. Main question is about MPPT 100/20 and BMV 712 to a shunt. Having some particular questions on the MPPT readings.


Is the battery reading on MPPT supposed to be the output readings from the Battery, or how much the Solar is sending to the battery?

The reading on the MPPT is 10amp, while the reading on the Shunt BMV is 4 amps.

Can the difference between these values be that far off? And if so, which one is the more accurate?


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MPPT SmartSolar
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2 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

If everything is wired correctly than the MPPT produces 10A but only 4A are going into the battery because you have some loads running and those loads need 6A.

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donnyv avatar image donnyv commented ·
So that 4 amps on the BMV, is actually input into the battery, not output. I thought it was output.
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Justin Cook avatar image
Justin Cook answered ·

@DonnyV , the BMV shows net current, it is not specifically measuring "in" or "out", but rather measuring the net overall. If you have 10A in and 6A out, it will show 4A in; if you have 4A in and 10A out, it will show 6A out.

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donnyv avatar image donnyv commented ·
Yes, that makes sense now. In your second example, the 6 out would be reflected by a -6 current, correct?
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Justin Cook avatar image Justin Cook ♦♦ donnyv commented ·
Correct! Well, assuming that the shunt is connected correctly, of course. If a 6A load is showing as 6A instead of -6A, then the shunt is backward :-P
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donnyv avatar image donnyv Justin Cook ♦♦ commented ·
Got it! Pretty sure it’s working correctly. I haven’t noticed any negative loads with no appliances on. Thanks, marking your answer accepted
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