question

ae0mt avatar image
ae0mt asked

BMV-712 and SmartSolar 100/30. Temp or Midpoint?

Hello everyone.

I currently have a BMV-712 installed in my Travel Trailer, and I have upgraded the batteries to a pair of 6V deep cycle golf cart batteries. I am currently using the auxiliary input to sense midpoint voltage of my battery bank.

In the near future I plan to install a SmartSolar 100/30 MPPT charge controller, and I have read that it can read the temperature and I believe voltage from the BMV-712, and adjust it's charge parameters accordingly.

In my case, I only have one possibility, temperature or midpoint voltage as an option. Is it more beneficial to sense temperature or midpoint voltage? Is there a way to sense both, such as the Smart Battery Sense?


Thanks everyone.

MPPT ControllersBMV Battery MonitorTemperature Sensor
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2 Answers
Charlie Johnson avatar image
Charlie Johnson answered ·

It is my opinion that temperature sensing of a battery bank with the associated adjustment of charging voltage is more important than mid-point voltage sensing.

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ae0mt avatar image ae0mt commented ·

I think you are likely right, but one more thing to consider. The temperature sensor is $20. The Smart BatterySense is $40. It will cost $20 to sense temperature, and another $20 for midpoint voltage detection. Is midpoint voltage detection worth $20?

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Mark avatar image Mark ♦♦ ae0mt commented ·

In my opinion it's worth much more than that.

It can pick up an imbalance in your batteries early on, so that you can potentially implement some form of corrective action before it's too late and you destroy an expensive battery bank.

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Justin Cook - Bay Marine Supply USA avatar image
Justin Cook - Bay Marine Supply USA answered ·

@ae0mt, if you connect the Smart BatterySense and pair it with the SmartSolar MPPT via a VE.Smart network, the MPPT will adjust its charge parameters based on the temperature readings sent from the BatterySense... that way you get to keep your midpoint voltage monitoring and you get your temperature compensation at the same time.

That being said, of course the BatterySense will only attach to one of the batteries, so there does exist a possibility of one battery running hot and you not knowing about it, but realistically so long as they are same type/capacity/age/location, the temperature differential between the two should be negligible.

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ae0mt avatar image ae0mt commented ·

They are the same batteries, purchased at the same time. In theory, they should be the same.

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Justin Cook - Bay Marine Supply USA avatar image Justin Cook - Bay Marine Supply USA ♦ ae0mt commented ·

That should work perfectly then. When you get the SmartSolar MPPT, use it to set up a VE.Smart network (local area Bluetooth network), then connect the Smart BatterySense to the batteries and install it (it sticks to the battery using double-sided tape) and connect the SBS to the VE.Smart network; then you can open the MPPT again using VictronConnect and it should confirm that it's receiving temperature and voltage information from the SBS; once the SBS is connected, you can also edit several settings in the MPPT such as low-temperature cutoff that were previously inaccessible.

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