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john-strein avatar image
john-strein asked

Smart Shunt BMV-712 Questions

!. What is the parasitic draw of the BMV-712 with no loads applied to the battery?


2. Can one put a switch on the power feed to the shunt to essentially shut down the shunt and the round faced display WITHOUT losing data or settings?


3. Is there someway to shut off the round faced display while away from the cabin for days/months at a time?

BMV Battery Monitor
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6 Answers
Sarah avatar image
Sarah answered ·

Hi @john strein, when the backlight is off the BMV-712 has a draw of less than 1 ma. It is likely that the degradation of your batteries over time will make this negligible. If you are worried about keeping batteries full charged I would suggest a small solar panel (perhaps removable) and controller. You will need to ensure that the voltage out put on the panel is higher than your battery voltage otherwise it won’t work. Also the data is stored in non-volatile memory so it can be switched off without loosing the config or logs. https://www.victronenergy.com.au/upload/documents/Datasheet-BMV-712-Smart-EN.pdf
Sarah.

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kevgermany avatar image
kevgermany answered ·

To add

The shunt of the 712 has electronics which also draw, so simply disconnecting the display may reduce draw, but won't eliminate it.

Thee main shunt cannot be disconnected.

If you really wanted to go to the trouble, you could disconnect the battery positive connection(s) to the shunt which would disable the electronics. But as Sarah pointed out it's pointless due to the very low internal draw. It would also introduce a point of failure, unless you did it by removing the inline fuse(s) of the positive connection(s).

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john-strein avatar image
john-strein answered ·

Thank you for the replies.

Here is the situation: These batteries will sit idle at our remote cabin for up to 4 months. What would you do in this situation? Is the parasitic draw so little I should not worry about it or.............?

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airstream-installer avatar image
airstream-installer answered ·

Are the batteries lithium? If so just make sure they have at least 75% SOC and disconnect the negative battery lead or install a disconnect switch and turn them off.
if they are not Lithium then you will need some sort of charge current going to the batteries or they will loose there SOC too much over 4 months and this will damage the batterie.

I would not worry aboutthe BMV causing enough draw to matter.

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tmartin000 avatar image
tmartin000 answered ·

Honestly, I thought Lithium Batteries like a charge of about 40% for long term no-draw storage???

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airstream-installer avatar image airstream-installer commented ·
Guess it depends on the brand.
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john-strein avatar image
john-strein answered ·

My setup does indeed have LifePO4 cells making a 12v battery.

I do have a cutoff switch on the battery box but it connects/disconnects the POSITIVE lead.

Are you suggesting I need to have the cutoff switch on the NEGATIVE lead or have one on both leads?


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