question

overland34 avatar image
overland34 asked

My BMV-712 shows less amps in than does my MPPT charge controller by half.

I purchased the BMV-712 to monitor my batteries because I was not satisfied with the limited information I got from my Charge controller, as it only shows input from Solar, not from Shore power or 7-Pin connector from tow vehicle, and I had no idea how many Amps I was consuming. When I installed the BMV-712 Monitor I found that it consistently shows about half of the Amps input from Solar than does the Charge Controller. I even changed my charge controller from a Renogy brand to an MPPT from Victron, thinking that maybe the Renogy was of bad quality and it was not correct... only to find the exact same problem. The Monitor shows approximately half the Amps input from Solar that two different charge controllers do. I followed the recommended settings from the manual using the app, and the shunt was installed per directions. I don't know what is going on.

BMV Battery Monitor
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Vance Mitchell avatar image Vance Mitchell commented ·

Just to clarify, do you have the vehicle hooked up now?

Some of your charge potentially could be going to your vehicle battery.

If the BMV is installed correctly it will only measure the amps going in or out of the battery bank it is connected to.

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spirou avatar image spirou commented ·

Simple, something else is consuming the solar output (fridge, heater, lights etc.)

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1 Answer
Rob Fijn avatar image
Rob Fijn answered ·

Hello Overland34, it is possible to calibrate the Zero Current. Maybe this can solve your problem.

Menu 09

09. Zero current calibration
If the BMV reads a non-zero current even when there is no load and the battery is not being
charged, this option can be used to calibrate the zero reading.
Ensure that there really is no current flowing into or out of the battery (disconnect the cable
between the load and the shunt), then press SELECT.

You can only do this when you have selected the correct SHUNT. By default is this already connect: check menu 65 and 66

65. Shunt current
When using a shunt other than the one supplied with the BMV, set to the rated current of the
shunt.
Default Range Step size
500A 1 – 9999A 1A
_______________________________________________________________
66. Shunt voltage
When using a shunt other than the one supplied with the BMV, set to the rated voltage of the
shunt.
Default Range Step size
50mV 1mV– 75mV 1mV


Hope this helps.

regards, Rob

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