I have a setup with 3 Multiplus II devices and a very large battery (144kWh), combined with an Ekrano GX and 2 EVCS NS. My connection to the public grid is 3x 40A. I don’t have any PV yet. I am running into a problem when trying to charge my two cars simultaneously, using the battery. One car charges on 1 fase with 7kW max. and the other on 3 with 11kW max. When they charge at the same time, one phase hits 11kW and after a while my main fuse pops.
What’s even worse is that the other two phases start supplying back electricity from my battery to the grid.
How can I prevent this? The whole reason I got this setup, was that I heard that the GX device would monitor everything and throttle back the EVCS’s whenever needed. I want to be able to charge the two cars simultaneously from the battery and I don’t want to deliver any electricity to the grid. I hope someone can help me with this.
What model multiplusses do you have? Are they big enough to supply the ev’s at the same time?
If you configured your ess with for instance 50w grid setpoint (standard) than it will try to keep it at 50w, thats why its feeding grid, its balancing to keep the setpoint
Whats your ac in current limit on the multiplusses?
That’s happening on purpose when you configure the system to do “Multiphase-Balancing: Total of phases”. It will be a saldated 0 then (if you have a saldating meter) and you then usually pay nothing for the 4644 pulled on L1.
But your issue seems something else, no matter if you use individual phase mode or Total of all phases, the MP on Phase1 should easily provide enough power to not have your breaker tripping on 11 kW phase load (given it is not a MP3000, the 5000 should do). Are you sure on the 3x40A Grid-Figure? Which AC-voltage does your system run on?
Thanks both for your reply, it is very much appreciated. The grid is 230V and I am sure I have 3x40A. The multiplusses are the 10000. They are not the problem, the overload of a single phase and the GX not correcting this is. I am trying out now to charge simultaneously with ‘Multiphase-Balancing’ set to measure per phase. Hopefully the GX wil throttle in time. Will post my results here.
The gx cannot correct anything on assymmetric loads.
But with a MP 10k on each phase there is enough invertering power to keep your grid well bellow 40A per phase.
So, you should check if eventually your battery is not able to keep up the required DC load after a while. Rated from capacity it should be possible, but if it’s diy, unsuitable BMS configuration or sizing may limit the dc power drained by the MPs by requesting a way to low discharge current limit.
They then will opt to overload the grid rather than your batteries.
3x40 or 3x35 is not common in NL 3x 25A is, because 3x35 is 3 to 4 times more expensive (about a €1000 a year just for the connection) than 3x25A (about €300 a year)
In stead of exporting on the phase with most demand, it is importing. I don’t want this of course, I want the battery to be used. The GX is not throttling, even after 5 minutes. When I manually throttle the second charger (that is charging 7kW on the single phase), this is the result:
Your doing 11kw on 1 phase thats not possible without drawing from grid, the 10k multi is only 8000w at 25degrees so logic its drawing the rest from grid
Yes, the grid remains below 40A, I’m sorry, it was not the main grid for phase 1 fuse that tripped, but the 40A fuse that secures the EVCS dealing with the 11kW.
Ah - well, neither the gx nor the inverter nor the evcs knows anything about that fuse.
So, you have to ensure the 40A limit on that either with permanent safe settings, or dynamic through Nodered.
I wouldn’t bother all too much with that, limit both cars to 28A + 10A and they’ll charge fine over night without issues.
Then go with “Total of phases” if you have a saldating grid billing? You are then not feeding “battery to grid”, you are technically just exchanging it for the additional power you need from the grid on L1.
Isn’t the ‘Grid Current Limit’ in the multiplus settings section of the GX intended to keep everything below 40A per phase? I mean I did limit that tot 40A and I think this is the reason why the text turns red when viewing the overview screen and a phase exceeds 9200W.
Naah, I don’t want that. Paid to much for this setup to not use it to its maximum limits. I want to be able to charge two 22kW cars with the system throttling down automatically when necessary and not export anything to the grid.
Aaraf, with all due respect, I am afraid you are not understanding the basic (electric) “math” here…
IF you don’t want to EXPORT anything to the grid, and you don’t want to IMPORT anything (= i.e., to cover everything from your batteries), this is equivalent to the situation if you would run your system in the “off-grid” scenario – so let’s pretend for a while that you don’t have grid available.
If we ignore the grid, we need to “understand” and “solve” each phase individually – so let’s focus on a single L1 phase for now
Your MP 10000 is capable of supplying ~8000W, this is max 35A @ 230V
Wallbox and EV chargers works in such a way, that Wallbox gives the EV “max current you can pull”, and the car will “pull up to maximum current from ALL available phases simultaneously”.
22 kW charging is 3x 32A. 11 kW charging is 3x 16A. 7.2 kW is 1x 32A or 2x 16A
As you can now see, your Multiplus can only supply 35A – so either 1 car 32A, or 2 cars 16A each, or 2 cars 20A+15A. If you want more, you need grid to assist the Multipluses
‘Grid Current Limit’ is the limit on the Multiplus INPUT (from grid). Not on the output! Your 40A fuse BETWEEN Multiplus and 2x EVCS has nothing to do with that. Nor Multiplus, GX, nor even EVCS knows about this limit (fuse).
EVCS can “know” about it by limiting “Max charging current” – that’s what @dognose suggested (limit the EVCS to 28A + 12A – it would still overload your MP, because MP can supply “only” 35A, but you get the point).
EVCS’s “Auto” mode works “only” in such a way it limits the consumption by EVCS to match surplus solar power – if you don’t have Solar, Auto mode is not for you.
Soooo, IF I understand correctly your desire, which could be reformulated like this:
I understand my limitation of 35A max per phase, but I don’t want to “statically” limit my EVCSs, because sometimes I would like to charge my EV in full sppeed from “Left”, sometimes from “Right” EVCS – thus I need some clever “throtling” that would match my custom setup and needs…
… then your only solution will be NodeRed script, that will adjust the max current of individual EVCSs based on your desired rules (e.g., not to overload 35A per phase to avoid grid involvement, decision which EV will be throtled and how much, etc. etc.).
It must be said that the required NodeRed script to solve this use-case can be made pretty easily.
Please excuse me, and disregard what I have said if my understanding of your needs is incorrect O:-)
Thank you Falkon for your answer. I figured out that the best way to handle this situation for is with a Node-RED script that throttles the two EVCS’s depending on the available capacity. It seems to work quite well, though I found out that I have to turn off Bluetooth on the EVCS’s to ensure a stable network connection and ended up using MQTT for the most reliable performance. By using 35A as my limit per phase, I minimize grid usage.
In a 3-phase Victron ESS setup, you must install the ESS Assistant on all three units (all phase masters and any slaves). This looks like you just install it on L1 so only L1 is working as ESS.
