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jdhaasdmb avatar image
jdhaasdmb asked

Can setting low temp cutoff in BMV-712 stop AC converter charging?

I am running the BMV-712, Battery Smart Temp Sensor and the MPPT 100/15 with a 2x LiFePo4 200amp hour battery bank. The battery bank has BMS onboard but a low temp cutoff is not included unfortunately. I have things set with the MPPT to cutoff charging at 3deg C but that is only when charging from solar. It looked like if I set the BMV-712 relay low temp cutoff setting to 3deg C, it would cut charging regardless of whether it was from solar or the AC charge converter but my tests are showing the relay closed when it's supposed to be, however the AC charge converter is still charging the battery bank. Any thoughts or ideas? Thank you in advance.

BMV Battery MonitorchargerTemperature Sensormppt chargingac
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2 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

What is your other charging source? Does it have a control input? If not, you will probably need to use an external relay to interrupt the AC input to the charger.

The other option is to insert a battery protect in all charging paths to the battery and feed that with the BMV's relay.

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jdhaasdmb avatar image jdhaasdmb commented ·

Thank you Kevin, My charging sources are the AC charge converter when connected to shore power, a suitcase solar unit I connect to the input on the side of the RV and the 12v source from the tow vehicle when connected to the 7-pin wire harness.

I thought the battery protect only protected against voltage, not temperature?

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avk13 answered ·

@jdhaasdmb were you able to resolve this issue? I have a similar predicament for my class A. I'd like to convert to LiFePO4 batteries, but would like to protect my battery from charging from the converter charger below 32F with the BMV-712 using the temp sensor. Were you able to do this?

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