OCTO GX - 4 BlueSolar MPPT - system voltage issue

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Wayne asked Dec 31, '20

OCTO GX - 4 BlueSolar MPPT - system voltage issue

Hi there

I have 2000W solar through 4 BlueSolar MPPT's 3x30 1x60amp with VE Direct cables to my Octo GX, also connected is my 12/3000/120 Multi.

Batteries are 2x RB300Ah Relion lithiums.

I have a BMV712 smart also connected to the Octo via VE Direct.

I am having the same issue as many with the MPPT battery voltage being different to the BMV voltage, I can see my controllers going to float as low as 70%SoC.

I have been told if I instal a Bluetooth sensor to the battery bank and network it to the BMV712 that this will become the default voltage for the entire system, has anyone done this with an Octo or can confirm it is correct.

TIA

Wayne

battery system voltage system integration

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Answer 1 · 2020-12-31T10:23:03Z

JohnC answered · Dec 31, 2020 at 10:23 AM

Hi @Wayne

I can't answer your specific query re networking in a BT V-sensor, but it shouldn't really be necessary to do that.

The Octo has DVCC, designed for sharing such data with all VE.Direct devices. https://www.victronenergy.com/media/pg/2556-GX_Device_Manual_Cerbo_GX/en/dvcc---distributed-voltage-and-current-control.html

The BMV's V is likely the default source, and all mppt's should get that supplied to them. Without BT.

How this works in with your battery's BMS might need checking, but you haven't mentioned a bms..

That's the SVS option, the STS you shouldn't need with Li's, and SCS may also be useful for Absorb/Float switching.

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Answer 2 · 2020-12-31T10:41:42Z

seb71 answered · Dec 31, 2020 at 10:41 AM

"I am having the same issue as many with the MPPT battery voltage being different to the BMV voltage, I can see my controllers going to float as low as 70%SoC."

The conditions for the MPPTs to switch to float have nothing to do with the BMV SOC displayed value.

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Answer 3 · 2021-01-01T00:13:13Z

Wayne answered · Jan 01, 2021 at 12:13 AM

JohnC you were on the money.

Thanks so much, I have been able to use DVCC to point the Multi temp sensor as the default for the system and the same with the Voltage from the BMV as the default for the system.

Did a reboot of the Octo and all the MPPT V's have come into line with the BMV and all have gone to bulk and working as they should.

Thanks again!!

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