question

Eugene avatar image
Eugene asked

Older Multiplus with BlueSolar HUB-1

Hi there,


This is my first post on this forum, and I'm quite new to Victron products, solar power and electronics in general.

I have an old (donated) MultiPlus 24/3000/70-50 and BlueSolar 150/85 from years ago. The Multiplus is product code 1910 with firmware version 209 (I updated this myself, it was running 1xx).

Currently, the inverter and MPPT are connected to the batteries, but there is no intelligence. I'd like to run the HUB-1 assistant on this device to allow the MPPT to serve AC loads when the batteries are full. I'm starting to think that this is not possible on the older MultiPlus that I have. Is that correct?

My ultimate goal is for load-shedding/grid-blackout resilience and to NOT feed back to mains. Ideally, the inverter will run from solar, failing which it will run from mains, failing which it will use the batteries. Solar -> mains -> batteries.

If this device can not run the HUB-1 assistant, is there another way to achieve this?


Thanks in advance!

battery chargingsolarAssistantssoftwaremultipus
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8 Answers
Alexandra avatar image
Alexandra answered ·

@edebeste

Hub 1 allows feedback to grid.

Use virtual switch instead to prioritize solar.

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Stan avatar image
Stan answered ·

If you dont want to feed back to the grid, do not use ESS or HUB assistant.

It is better to have AC loads on ACout and use Virtual switch "Ignore AC".

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Eugene avatar image
Eugene answered ·

Thank you @Alexandra and @Stan, I configured the device as described in the PDF (disabled charging for MPPT to take priority and enaled the virtual switch to ignore AC on certain conditions). All appears to be working there.

I do notice some odd behaviour, though. I have a RPi4 running Venus OS and the Multiplus is connected to it via MK3USB. The BlueSolar VE.Can is NOT currently connected to the device (I am waiting for delivery of a Cerbo GX). According to the Remote Console/VRM the battery SOC is reducing, even though the voltage seems to stay constant?


1665912095206.png


I have had the battery % drop from 100% or 97% regardless of the constant 28.8. My understanding is that it wouldn't matter if I connected the BlueSolar to the GX device anyway, as my Multiplus doesn't and can't run a firmware version high enough to support the GX device feeding it information from the solar charger, as per the bottom of section B in 5.2.2 here https://www.victronenergy.com/media/pg/CCGX/en/configuration.html#UUID-519caeef-b347-2a6c-498a-a163ffc680a3.

Anything I'm missing here?


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Stan avatar image
Stan answered ·

Probably you have reached the Float, so no current goes to battery and battery voltage is going down to float voltage. Usually the float voltage is around 3,35V per cell.

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Eugene avatar image
Eugene answered ·

@Stan thanks for the response.. The float voltage is 27.6. I have reached it, but it seems to be going down further still, even though I'm constantly at 27.6 now. I am a little confused.


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Stan avatar image
Stan answered ·

It is because of very flat charge and discharge curve of LiFePo4 chemistry.

Float voltage at 3,45 per cell is little bit high.

You could watch at Andys videos on his yt channel - off grid garage. There is a lot of information about Lifepo4 cells.

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Eugene avatar image
Eugene answered ·

Sorry @Stan, I should have been clear from the start. I am on lead-acid, not LiFePo4

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Alexandra avatar image Alexandra ♦ commented ·

@Eugene

There is no shunt in the multiplus, so it will be trying to calculate the battery percentage based on ac loads and what you jave progrmamed into the internal battery monitor.

So what are your settings there and how much battery do you have?

To be honest going offgrid the best thing is to have a shunt if you don't have can connected batteries. And not all the devices are reporting to the GX so it will be unaware of the charge from the mppt.

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Eugene avatar image Eugene Alexandra ♦ commented ·

Thanks for the response, I appreciate it.


As mentioned, I don't necessarily want to go completely off-grid. I intend to use the mains when the solar output is low.


Here is the current configuration:

untitled-diagramdrawio.png


I hope that clarifies some things.


Here are the settings I have according to VEConfig (I exported it from the app)

settings.pdf


I'll look into getting a BMV or something for more accurate battery measurement and connect it up to the GX (once I get my Cerbo GX). Do you know whether these old Multiplus and BlueSolar units will work intellegently if connected to the GX? Or are they just too old?

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Alexandra avatar image Alexandra ♦ Eugene commented ·
@Eugene

They are not controlled by the GX, but they do report to the GX and then by default to the VRM if you have that set up. (I have seen and checked up on some on a CCGX)They use their own internal algorithms, which most mppts will do anyway with non can connected batteries.

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Eugene avatar image
Eugene answered ·

Paraphrasing one of the questions in the reply above to the main forum:

Can anyone confirm if the older 19xx model Multiplus and the older metal frame BlueSolar 150/85 will work together with a Cerbo GX?

I would like to connect a BMV along with these two for my 2 lead acid batteries.

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