Hi All, I have recently moved from a single phase to a 3 phase supply. In the UK this means a 3X100A supply.
I am currently running a Multiplus-ii 15000/48/200. It had been my intention to add two more of these to make the single unit into a full 3 phase system but I notice that the Multiplus 20kW (not MPii) has recently become available. The extra power from three of those is quite attractive in my situation but is it possible to make a Multiplus G100 and G99 grid compliant in the UK? I have fitted quite a lot of MPii as domestic ESSs but never a Multiplus.
There isn’t a manual online for the MP 20K yet. There is a datasheet. Regarding anti islanding it says “refer to the certificates on our website” there aren’t any certs for the 20k yet either. A quick look on the UK energy networks association website shows that no Multiplus units have ever had UK certification.
Does fitting the anti-islanding box get round the lack of certification? There is a small additional problem there I that it is only rated for 63A but I could re-make it with 100A gear I guess.
Is it likely that a 20kW MPii will appear at some point? Unfortunately I need to make up my mind regarding 15kVA MPii or 20kW MP by mid Jan. Any thoughts?
What products are you referring to? Nothing new above 15kVA available yet.
The community, as per guidelines, does not comment on future products or rumours.
I think @kWh.Engineering means the MultiPlus-CL 48/20k/250-100 — a few suppliers online already have it listed for sale. I’m not sure about availability, though. It wasn’t in the Q4 2025 price list, and from what I can see, the Q1 2026 price list isn’t out yet either.
One thing worth pointing out: these new models — 4.5 k, 6.5 k, and even the 20 k — have a maximum DC operating voltage limited to 60 V. The same goes for the Multi RS, by the way. For some of the less typical battery configurations, this can be a huge deal. I personally use a 15S Li-Ion NCM system (charged up to 61,5V), and I’ve seen people here on the forum running 18S LFP setups.
Unfortunately, I’m not able to offer any help regarding grid compliance in the UK.
The chargers on these new MP 20K units are rated at 250A each so 750A total if they will actually run flat out. I was planning a 96kWh 16S battery initially which would therfore charge at ~0.78C
It all depends on how the battery pack is built and on the parameters of the cells themselves. Either way, with these parameters it will actually be quite a bit less than it might seem.
Assuming a charging current of 750 A at the nominal voltage of a 16S pack, that gives a charging power of:
750 A × 51.2 V = 38.4 kW.
With a 96 kWh pack, that works out to:
38.4 / 96 = 0.4 C.
A better approach would be to reduce the charge current to around 380 A and charge the pack at about 0.2 C. That way, the batteries will last much longer.
0,78C charging would require charger capable of delivering almost 75kW to the battery.
The multi traditionally also had single input relays, not dual which is commonly needed for compliance.
If that is the case an external relay would he needed for ESS.
Victron inverters are unfortunately not on the G100 compliance register.
Several people (here and elsewhere) have discovered this. My DNO is insisting on G100 compliance for our install which leaves me looking elsewhere for inverter options sadly.
There might be options to add a 3rd party, standalone g100 export limitation device to your system but that doesn’t make sense when they are almost the same cost as the inverter. I’m also not convinced the DNO will accept them anyway.
I’d happily be corrected on this but I think Victron’s position is still the same; not actively pursuing G100 compliance
Sorry that you’ve had that experience. Which DNO are you with? I’ve had several Multiplus ii units (which are on the ENA type test register along with easy solar and quattro for G98/G99 at least) signed off across two different DNOs and never had issues. None of the Multiplus units are on the ENA register though.
There is a Victron G100 compliance statement on the web - have you tried sending your DNO that?
Thanks all for the input. I’ve spent most of the day drawing this system out and the more I have though about it, the 20kW units make everything bigger, more complex and more expensive for relitively little gain. When you factor in power assist and other AC coupled inverters you realise you have to start desiging a whole load of the AC infrastructure to handle 200A per phase which gets a bit nuts domestically. I’m export limited at 23kW anyway but I did quite like the idea of being able to grid charge at over 40kW. Given the deadline I have and the fact we are still awaiting full details of the 20K I’ve decded to use two more MPii 15kVA units on this project.
I’m with SSE, up in Scotland. I haven’t proposed a Victron inverter yet but I’ll give it a go. Perhaps the combination of pre-existing g99 compliance plus the statement from Victron on G100 compliance might work - TBC. Which DNOs have you dealt with previously?
I’ve done at least 8 G99 Victron installs with SSE South (and I’m pretty sure that the departmant doing the G99 stuff is shared North/South - I sometimes get calls from then on Scottish numbers) - never a quibble about G100. I’ll caveat that by saying that If you are not already a DNO approved installer they may want to witness test your first 2 installs, as they did with me, I think that cost arround £360 a time. It was actually a really good session with an extreemly knowledgable chap from the DNO - I learned a lot. My first two weren’t Victron (Solis and Givenergy I think) and G100 was discussed. As I recall the main thing the chap was concerned to see on G100 was the behaviour of the system when the grid meter was disconnected and that the export limit was set somewhere and password protected from the user.
