Is this thing actually working?

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mike-smalley asked Jun 22, '20

Is this thing actually working?

BMV 712 Smart, house battery is a Battleborn LiFePO4 100 Ah which is charged through a Redarc BCDC (no solar yet) - settings are

Batt. Cap. 100 Ah, Charged Voltage 13.9, Discharge Floor 20%, Tail Current 4.00%, Puekert Exp. 1.05, Eff. Factor 99%.

Relay: Low SOC 20% (all alarms by default set to Disabled).

Display: all set to on except Mid-voltage display.

Misc: Shunt current 500A, Shunt voltage 50mV, Aux input Starter battery.

Since initially setting these settings there has been no difference to the display, or percentages.

I'd like to be able to see the current state of charge for both the house (aux. LiFePO4) and the vehicle start battery: how and what do I need to do differently to see the actual state of charge of both?

Thank you.

VictronConnect

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Answer 1 · 2020-06-24T21:01:42Z

irwinr answered · Jun 24, 2020 at 09:01 PM

"no difference to the display, or percentages."

I'm not sure I understand: Are you saying when you apply a load to the battery, you don't see the load current show up on the display? Likewise: When you start charging, do you not see the charging current displayed?

If so: Do you have the shunt installed between the negative post of the battery and your chassis ground? You have to make sure that the only thing attached directly to the battery is the shunt. Everything else needs to attach to the opposite end of the shunt to ensure all power flowing into or out of the battery also flows through the shunt.

Did you make sure the connection between the shunt and the BMV is good? I think there's an inline fuse in the cable that connects from the BMV to the shunt: make sure it's not blown.

If you want to monitor the state of charge for your starter battery you'd need a second BMV and shunt combo. The single BMV can monitor the *voltage* of a starter battery, but not the state of charge of a second battery.

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