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Andrew Burnett avatar image
Andrew Burnett asked

Unable to set shore power above 32A

Using a Multiplus II 3000 in an ESS configuration, and using scheduled charge settings to make the most of low cost off peak power at night.

I've noticed when loads are high, charging a car for example, scheduled charge does not charge the batteries, in fact the multi inverts to help out, thus draining the batteries.

I think this is because the shore current setting has a max of 32A, when my loads go over this the multi "helps out".

A this is a ESS, and the house is fitted with a 100A fuse i want to be able to set the shore power above 32A, in VE Configure.

shorelimit32.jpg


Can this option be added to the next release?

MultiPlus Quattro Inverter Charger
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3 Answers
bathnm avatar image
bathnm answered ·

What version Multiplus do you have. There are two different transfer switch options, a 32A and a 50A. It sounds like you have a MultiPlus with a 32A transfer switch.

The product name is constructed like this:

DC Voltage / Output Power / Charge current - Transfer switch

so as an example 12/3000/120-32 is a 12v DC system, 3000W, 120A charge and 32A transfer switch.

To get 50A transfer the model needs to have a -50 at the end.

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Andrew Burnett avatar image Andrew Burnett commented ·

Thanks @Bathnm I have a MultiPlus II 3000/32 so I guess this is why I'm seeing a max of 32A in my settings, battery system is 48V for info.

I'm using the Multi as part of a ESS, basically the below, apart from I'm using the CT clamp direct to the Multi rather than an ET112.

basicmulti.png

The issue is, if the Multi sees more than 32 Amps passing through the grid feed during scheduled charge, it switches to be an inverter to help out. Of cause during normal operation in an ESS I want the import from the grid to be as small as possible, but when set to scheduled charge I want it to charge, not discharge.

I think there are two fixes, both need to be changed by Victron.

  • Allow shore power setting to be increased, regardless of the inverter/charger being used.

OR

  • Change the logic where the Multi helps out if scheduled charge is enabled
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ Andrew Burnett commented ·
The relays inside the MultiPlus are rated for 32A so pulling more than 32A through it can damage the relays.

Maybe you should connect some loads to AC IN instead.

Or switch to a 5000VA MultiPlus with 50A transfer relays.

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wkirby avatar image
wkirby answered ·

Thank you so much for attaching a diagram. It gives us a lot more insight. It seems you don't have any loads on AC-OUT at all. The MultiPlus provides the loads during the day out from AC-IN.

We can also see that you have an external current sensor. Bingo.

You want this maximum value to be more than 32A?
1643321516877.png


Well, if you tick the box which says "External current sensor connected" then you can set this higher.

1643321636138.png

It's still only 50A, but it should help you out.
There is a maximum full scale measurement within the MultiPlus, so it make sense to me why it's pegged at 50A. Bigger MultiPlus units would likely be able to go higher, I'm not 100% on that though.

Otherwise, you would need to move the current sensor within the DB board and select circuits that you wouldn't want it to see. Loads placed before the sensor would not be counted, but they would not ever be powered by the MultiPlus either, so it's a bit of a balancing act.


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1643321636138.png (20.8 KiB)
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bathnm avatar image bathnm commented ·
That looks like a possible bug to me! I would not trust that to always be the case. That limit should surely be to protect the MP, and if the MP only has a 32A transfer switch that is what its limit should be.


I wonder if the car charging is connected before the sensor if that would help?

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wkirby avatar image wkirby ♦♦ bathnm commented ·
There is no current passing through the MultiPlus in the configuration that it is set up in. See diagram posted earlier.

The only current going through AC-IN will be maximum ~4A when charging and maximum ~8A when inverting. These limits are the MultiPlus' power pack limits.
The MultiPlus observes the current going through the sensor directly from the network to the loads, this current does not go via the MultiPlus AC-IN or AC-OUT terminals.

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Andrew Burnett avatar image Andrew Burnett commented ·
@WKirby Perfect, I'll get this setting changed and give it a blast tonight. Really appreciate your help.
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wkirby avatar image wkirby ♦♦ Andrew Burnett commented ·
Excellent, do let us know.

I'm going to move this question to Q&A as it isn't really a modification, it's a configuration question.

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Andrew Burnett avatar image Andrew Burnett commented ·

@WKirby Sorted! I've been hacking around on this one for just over a year. It wasn't until I realised the shore power setting was causing my config issue, but couldn't get it above 32A.

Change made in VEConfig, with a bit of testing I realised I also needed to change the related setting in the ESS assistant, which I could also then be take up to 50A:

img-8524.jpg

And then success:

img-8525.jpg

Car charging and batteries charging, no more MP helping out, up to the 50A limit anyway but I can work with that.

Thank you

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img-8525.jpg (141.6 KiB)
wkirby avatar image wkirby ♦♦ Andrew Burnett commented ·
Excellent, good to know it's worked out in the end.

I hope you get to keep your tariff. My Octopus Go tariff is up in 9 months time and they are going to take it off me unless I buy an EV. Like you, I'm wringing every drop I can out of my 5p rate.

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Andrew Burnett avatar image Andrew Burnett wkirby ♦♦ commented ·

By luck more than judgment I fixed for two years with EDF with a economy 7 tariff of 8p so good till July 2023. Before then I'm planning to build a garden shed/office and roof it in PV and connect up to a MPPT RS. I also want to re roof the house to make room for some more panels and connect them to the other string on the RS. If only work did not get in the way of the DIY projects.

I've just upgraded the storage from 6.5kWh to 16kWh, hence me wanting to get the most of of those 7 hours. Currently run at about 71% night units, hope to get this up to 90% with the extra capacity.

Thanks again

Andrew

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wkirby avatar image wkirby ♦♦ Andrew Burnett commented ·
Octopus Go gives me just 4 hours, so I really have to get the hammer down during that time, yet I only have a 60A fuse. I'm peaking at 30A now so a 7kW EV charger on top of that would tip me over the edge.

I have 4kW of PV dotted about the place, I already have an outdoor office which is covered with PV :)
House roof could do with PV and it's SSW facing, but I'd do well to have the roof inspected first. Just need to decide if I get a regular grid tied setup, or just go DC coupled with a RS. FIT's are rubbish these days, so self consumption makes the most sense to me.

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neki avatar image
neki answered ·

What you need that in x time mp goes to charger only mode. Maybe you can do that whit pbc, and some raleys/ timers. I dont know what you have in system, gx or not and is it possible to play whit remote or not.


But what I can see you need switch between inverter and charger only and maybe your solution is on that, not to put softwer limits over hardwer limit


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