BMV and internal Multi battery monitor

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valentin-silvera asked Nov 28, '19

BMV and internal Multi battery monitor

Hello everyone. I have a system composed of the following elements:

1 Venus GX (Firmware 2.33)

1 Multiplus II 48/3000/35-32 (Firmware 456)

1 BMV-712 Smart (Firmware 4.03)

1 Smart Solar Charger MPPT 100/20 48V (Firmware 1.46)

4 Battery 105Ah in series, 48V

The battery is being monitored by the BMV:

Settings → System setup → Battery monitor → BMV-712.

I have two operation problems:

1) During discharge without grid (off-grid), with a C4 rate, it did not respect the configuration of the cut-off value of the state of charge that was SOC = 50% in the BMV. In repeated tests the cut-off voltage value was around 47.40V.

2) During recharge, the process does not respect the values set in the VEconfig3,

As shown in the image below:

The bulk stage was started with SOC = 95% instead of 80% and the load current was 5A instead of 10A.

In the following link: https://www.victronenergy.com/live/ccgx:start#battery_state_of_charge_soc say

“Note that the Battery Monitor setting in VEConfigure3 is irrelevant. For systems like this, changing this setting will have no effect on the charge - or any other parameters - in this type of system.”

In this case, when using the BMV, how can I configure the parameters for the loading stages?

battery charging BMV Battery Monitor

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Answer 1 · 2019-12-28T07:21:40Z

Paul B answered · Dec 28, 2019 at 07:21 AM

You maybe getting confused as the Battery monitor in the Inverter is NOT the BMV712

(I would turn off that battery monitor in the inverter and only work on the BMV 712 figures)

you should use the victron connect app and setup the BMV 712 if you have not allready done so as the battery size setting may not be correct in the BMV

The System starts in Bulk and then changes to absorption when the set voltage is reached

Also check that the CCGX has the correct Battery monitor selected it should be the BMV712

The VRM screen shots are from the BMV

the screen shot of the inverters internal bat monitor i a different VRM graph

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Daniël Boekel (Victron Energy Staff) ♦♦ commented · Dec 28, 2019 at 10:29 AM

Please do not turn off battery monitor in the Multi.

If it is enabled, and a BMV is chosen as battery monitor in the GX device, the Multi's SOC values will be overwritten by that of the BMV

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miya Daniël Boekel (Victron Energy Staff) ♦♦ commented · Jun 26, 2020 at 01:45 PM

Hi Daniel

I am seeing conflicting comments on different threads - about the Battery Monitor on the Multi. Can you clarify how my system should be set up ?

Venus GX connected to EasyPlus (by VE.Bus) and BMV712 (by VE.Direct).

In the Venus GX - I have the battery monitor set to the BMV712.

Using VE Configure in the EasyPlus I have "enable battery monitor" disabled. Should I have that ticked and on ?

Many thanks,

Tim

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Answer 2 · 2020-08-18T16:07:44Z

PeterM answered · Aug 18, 2020 at 04:07 PM

What is the correct answer as two conflicting solutions are presented - One solution - have both Battery Monitor in inverter and BMV enabled and the other solution disable the inverter's own battery monitor

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