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berndm avatar image
berndm asked

Multiplus 2 shutdown, when connection to bms is lost

Hello,

I have an off grid installation (absolutely no connection to the Grid) with two Multiplus 2 5k single Phase parallel, MPTT 450/100, Venus OS 3.11 on Raspi, SmartShunt and 30kWh Lfepo4 with jkbms and serialbattery.

When I installed the last update of VenusOS to v3.11 the serialbattery driver wasnt loaded automatically (reason unknown, i had to reinstall the driver) and after a few Minutes the Multiplus shutted down with "low Battery" warning. But the Smarshunt was available and showed 70% SOC and 52.8V only the JKbms wasn´t online (DVCC).

I want tu use DVCC to slow down charging the Batteries near SOC100% in order to enable good balancing.

Both Multiplus have Voltage Sensors connected and read out the same Voltage as JK and Smartshunt.

Both Multiplus are configured to shut down at 45V but if the BMS is not connected they shut down at any voltage.

Is there any possibility to configure the system not to shut down, when the connection to Venus OS or the BMS is lost (failback to the Multiplus voltage sensors)?

In an Off Grid situation its very annoying if the Multiplus shut down when the Battery has good SOC.

(Last time the power outage rendered the boot disk of my pc unusable and i had to reinstall the OS.)

Or is it possible to configure the Multiplus NOT to shutdown at all because the BMS will disconnect the battery anyway if the SOC is too low. I dont want or need the Multiplus to take care of my Battery.

Any help appreciated.

Multiplus-II
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2 Answers
nickdb avatar image
nickdb answered ·

No, if the system is configured with a managed battery it has a timeout and will power off if bms comms are lost. It is not immediate, else we could never update or restart the GX.

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berndm avatar image berndm commented ·
Yes, its about 10 or 15 minutes until shutdown.
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Alexandra avatar image
Alexandra answered ·

@BerndM.

You can remove the battery Comms cable. Reprogram (reset the mppt) the system to stand alone. Done.

That aside on the newer GX OS under DVCC you can remove the controling BMS...

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berndm avatar image berndm commented ·
I´m aware of this option, but i dont want to loose DVCC in Order to reduce the charging current when cells reach certain voltage levels so that the balancing works good (it doesnt work good at high charging currents).

Thanks anyway.

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