question

denis-l avatar image
denis-l asked

BMV 712 displays a very low auxiliary voltage

Most of the time the reading is right. But erratically the BMV displays an auxiliary battery voltage in the 5 volts range. When the problem occurs, the actual voltage at the B2 input is ok (ex.: 12,43V) (Measurement made with a handheld voltmeter). All other values including house battery are ok.

Last time this occurred, it lasted 20 minutes, then came back to wright values,

Connections are perfect. Firmware is up to date.

Any clues?

BMV Battery Monitor
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2 Answers
denis-l avatar image
denis-l answered ·

Finaly the BMV was not the cause. It has been displaying the real voltage.

The problem was from a defective relay.

Case close

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Denis L

First I would suggest to replace the inline fuse.

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denis-l avatar image denis-l commented ·

Thanks Guy,

Good idea but when the problem occurs the voltage is 12 volts directly at the B2 input. If the fuse would be defective the voltage would be 5 volts as the BMV displays.


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ denis-l commented ·

Maybe a half blown fuse?
https://community.victronenergy.com/questions/62099/is-it-possible-for-a-fuse-to-half-blow-answered.html

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