Integrating Multiplus ll with another brand of ESS (AlphaESS)

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robster asked Aug 17, '21

Integrating Multiplus ll with another brand of ESS (AlphaESS)

Newbie here, slowly getting to grips with a Victron install.

I currently have an Alpha ESS system on my property and I’m trying to integrate this with a Multiplus ll on the same phase.

The Multiplus ll is in also ESS mode, and has 24v/400ah LiFePo4 cells.

I’m having loads of issues during to install, which I’m gradually resolving with the aid of this forum & pl3nty of googling

The problem I’m having at the moment is the AlphaESS system is seeing the Multiplus ll as a load, so is discharging itself into it in order to charge the Victron’s LiFePo4 cells.

Is there any way of configuring it so the two ESS systems can run in parallel so they don’t keep charging each other’s batteries?

All advice gratefully accepted.

Regards,

Rob

Multiplus-II

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Modifications Space

Node Red Space

Answer 1 · 2021-08-17T12:38:06Z

markus answered · Aug 17, 2021 at 12:38 PM

Hi, the only thing I can think of, is to control one ESS system with the other.

Victron gives you the possibility of NodeRED via the Venus Large Image.

Venus OS Large image: Signal K and Node-RED [Victron Energy]

It might be possible to control the Alpha ESS with some modbus control commands via NodeRED.

Or vice versa - control the Victron ESS with the AlphaESS.

ESS mode 2 and 3 [Victron Energy]

This is far away from being newbie stuff, but possible with some tinkering.

I would suggest to make your live easy and sell the Alpha and just only use one system. The Victron system ;o)

By the way: This is considered a modification, so I move this Question into the modification space, where the tinkerers live. Maybe someone there can help you further with that.

https://community.victronenergy.com/spaces/31/index.html

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Answer 2 · 2021-08-17T13:06:01Z

robster answered · Aug 17, 2021 at 01:06 PM

Hi Markus,

Thanks for the info.

The AlphaESS system is great as an all in one system, but any modifications are limited & even they have to be sanctioned via the installer who has to contact China.

I like the versatility of Victron and, if I had my time again, I’d go straight to them.

For some reason the Alpha will try to charge the Multiplus, but not vice versa.

Maybe a little research will explain why & I can implement it on the Victron.

Thanks for moving it to the right section - maybe a fellow tinkerer will be able to assist further.

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shaneyake commented · Aug 21, 2021 at 05:57 AM

If the Victron detects that power is being exported it will use that power to charge the batteries instead. Most likely that is what is happening. AlphaESS does support AC-coupling but not sure if it has to be on AC output.

How are they wired up and do they both have grid meters?

Yes, I have run into the same problem with AlphaESS, very closed and will not give you any information. Things like Modbus control, seem very strange to them.

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Answer 3 · 2023-02-23T04:00:23Z

toin answered · Feb 23, 2023 at 04:00 AM

Im facing curently the same problem. I'm expanding the alpha ess system with victron, becaus the installer isn't answering to anything.

I have the folowing ideas how sutch a system could work but I'm not shure if they are stable

1. Installing an EM24 in front of the alpha meter and conecting the ACin (fused) inbetween, so that the victron only responds, when the alpha is empty or overloaded

2. Configuring the alpha as an solar system even though its not that, so that the multi plus knows what it is doing and can adjust or only respond, when it is delivering no more power

3. Seting the target value slightly positive or negative in the victron, so that the system with the higher value responds first and is the last one fully charged and the first one empty

Whitch of the workarounds might work ?

@Robster since the post isn't verry recent. If you have solved the problem, what was your solution ?

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robster commented · Feb 23, 2023 at 04:06 PM

Hi @Toin,

It was a while ago & I’m still trying to find a permanent solution. I have absolutely no programming skills so I had to do a manual workaround.

What I did was take the A/C feed from the Victron & pass the live wire through the AlphaESS CT that’s clamped on the incoming main A/C feed into the house.
That way the AlphaESS sees the Victron as a feed, so won’t supply/export to it.

That seemed to solve it for the most part. That Alpha doesn’t charge the Victro, for some reason the Victron knows not to charge the Alpha, both help out with the load sharing, & both charge their batteries with excess solar.

Occasionally the Victron gets confused, but a quick reset seems to sort it.

It’s not a perfect setup, as the wiring is a bit messy but it works for now.

I’m terrified of tidy it up in case it stops working! ;0D

Not sure if that helps you or not - I hope it does!

Cheers,

Rob

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toin robster commented · Feb 23, 2023 at 05:09 PM

Even though its not the perfect ready solution i was hoping for, but you gave me some new ideas, passin the victron through the CT of the alpha teoretically moves the conection in betwenn the Victron and alpha meters as described in my idea 1. So you gave me hope, that it will work

Maybe I'll pass the victon conection through the CT of both the solar (export direction) and grid (export direction), so it will charge thinking it is solar exported to the Grid (i want it to charge the alpha first untill full, because it has UPS for the whole house and pond). I also don't want to conect after the transfer switch

As far as programming goes I cold programm the programm that controls the ESS, but I'm the least talented person when it comes to communication protocolls, so i prefer a solution in hardware or the "normal" factory enabled settings

Hopfully in 6 to 8 weeks I can report if it is working as intended, write me agin then, maybe I'll find a permanent "Clean" solution.

Thank you verry mutch

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robster toin commented · Feb 23, 2023 at 06:56 PM

@Toin

I’m glad I could at least give you a few ideas on what else to try - I hope you find a solution for your particular setup.

Please do let us know how you get on.

…as our setups seem quite similar I’m particularly interested!

Good Luck!! :0)

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Answer 4 · 2023-02-23T06:59:45Z

ks4z answered · Feb 23, 2023 at 06:59 AM

If the Multiplus is grid connected you could use DVCC and set the charge limit to 0. This should prevent it from charging from AC.

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toin commented · Feb 23, 2023 at 03:35 PM

Well, I must explain a bit, the system curently consists out of an alpha ess 6kWh storage and and 5kWp solar system which are AC coupled. It will be expanded with one multiplus atached to 15kWh of batery (9 or 10 kWh nessasary and the rest as headroom for the future) and 7 or more kWp conected via Dc to the big batery. I'll also like to charge the victron becaue with the existing solar system because the alpha is limited to 1900W charging and so i sell sometimes 20kWh/d and the batey does not mange to bridge any night. With solution No1. this shoul be possible because the alpha does not notice any change to the system and sees the victron as power from the grid, so wont charge and is set to 0W export and so wont charge the victron. Is solution 1 pheaseable or do you see any problems that i dont ?

thanks Maximilian

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