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inhabor avatar image
inhabor asked

Why do MultiPlus and BMV show different states of charge for battery

Why the readings no my BMV-17 doesn't match the readings on my multiplus? The BMV reads 100% battery charge and the multiplus 95%.

Multiplus-IIMultiPlus Quattro Inverter ChargerBMV Battery Monitor
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Stephen Otto avatar image Stephen Otto commented ·

Do you have them both connected to a Venus device?

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3 Answers
ben avatar image
ben answered ·

Each of those has its own battery SOC estimator, and each can be configured independently as well. You need to set them up with config values so that they give you good results.

The hardware in the BMV is better at calculating SOC more precisely, so you should plan on using it primarily.

If you have a network with both devices and a Venus device managing it, you can configure the SOC coming from the BMV to "override" the one in the Multiplus, effectively replacing/ignoring it. Then both devices will use the SOC from the more accurate device.

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Christian Brenna avatar image Christian Brenna commented ·

Where can I change this SOC estimator so that BMV 712 calculates the SOC for my Multipluss 12/3000/120 ?

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Stephen Otto avatar image Stephen Otto Christian Brenna commented ·

I, too, am curious about where in the Venus/CCGX this setting can be found.

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Daniël Boekel (Victron Energy Staff) avatar image Daniël Boekel (Victron Energy Staff) ♦♦ Stephen Otto commented ·

Venus:

-settings

-system setup

-battery monitor

The Multi's SOC will then be synchronized with the chosen battery monitor. So any settings / assistants that use SOC as an input will also use this SOC.

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Petar Maksimovic avatar image
Petar Maksimovic answered ·

@Daniël Boekel (Victron Energy Staff) Is it possible to do the same using BMV-712 smart and Ve.Bus to BT on Multi, without VENUS device?

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Sorry @petarMaksimovic, this is not yet possible.

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blond2silver avatar image
blond2silver answered ·

Aside from the ability to choose which battery monitor in CCGX or Venus, the Multi would not know the DC consumer draw from various DC powered devices, but the BMV would due to the shunt/battery configuration. If that is the case - that there is a DC system, then there would be a Multic SOC to BMV SOC difference.

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