question

ppe-sammy avatar image
ppe-sammy asked

BMV Current displayed does not match reality (1A when should be >35A)...

I have been using a Victron BMV-712 for a few weeks now to monitor my battery as it charges/discharges.

Then the last few days it has been reading back invalid data and I'm not sure the cause.

My system/setup includes (in addition to BMV) a Multiplus 48/5000/70 which is charging/and at times discharging the battery (48V, 3.3kWh). The BMV is not connected to the Multiplus.

I have the MP unit in "Ïnverting Mode", there is no AC source, I have an AC load which is a 1.8kW electric heater

The BMV is reading something like 1026 (or 1.026A). This is impossible, there is hot air coming from the heater and no other power source available in the system except the battery.

Connected to the BMV, I have a VE.Direct to USB module which is plugged into a Raspberry Pi to log the 1s serial printouts.

If I use a serial terminal program I can see the incoming data and the "current" value against (I) appears to be wrong...

I've tried power cycling the unit.

Perhaps I have missed something, but it smells like a software bug or a faulty unit.

Any assistance would be muchly appreciated

BMV Battery Monitor
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1 Answer
wkirby avatar image
wkirby answered ·

I suspect a wiring issue in the first case.
You mentioned the the MultiPlus is not connected to the BMV, so how would the BMV measure MultiPlus current if the MultiPlus is not connected?
All devices need to be connected at or after LOAD /CHARGER terminal of the shunt.
The battery - is the only thing that should be connected to the shunt's BATTERY - terminal.

Would it be possible for you to show us a wiring diagram of how you have everything connected as it is right now, then we can more easily help to pinpoint the problem. Maybe you can take some pictures also.

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ppe-sammy avatar image ppe-sammy commented ·

I was putting a lengthy message together explaining my setup then I realized that the heater fan was on but not putting out any heat any more...

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