I want to use a Victron system purely as a backup power (UPS) solution for a supermarket. The installation is three-phase, and the average load during normal operation is around 18 kW.
My idea is to install:
3 × MultiPlus (10 kVA each) in a three-phase configuration (30 kVA total)
Approximately 30 kWh of lithium battery storage (with the possibility of adding more battery capacity in the future)
The purpose of the system is not to reduce electricity bills or to integrate solar PV. It would only operate during grid failures to keep the supermarket running. Based on the load, I estimate that 30 kWh of batteries could provide approximately 1–2 hours of backup, depending on the actual power consumption.
My questions are:
Does this approach make technical sense?
Has anyone implemented a similar system for a supermarket or other commercial facility?
Is using a Victron MultiPlus system without any solar PV, solely as a standby backup system, a common or recommended application?
Would it be a good practice to integrate all the Victron equipment, batteries, protection devices, and wiring into a single electrical cabinet as a complete, ready-to-install backup power solution?
I would really appreciate hearing about your experiences, recommendations, or any technical considerations that I should be aware of before moving forward.
Two common mistakes i have seen in systen sizing. Using an average load- not remembering what average actually means. And then also not checking phase balance.
Spread evenly over all phases?
And the peak per phase? The inverter nominal rating should cover the peaks on each phase. If being used as a UPS and not using ESS it can be asymmetric.
Third note.
The total useage of power will go up as the system has some self consumption power. And you will loose some in heat and inefficiency in battery charging.
The system is not asymmetrical; there is a general distribution. The maximum consumption value is 18 kW—not the average (I may have omitted that detail). So, would such a solution—assuming a technical assessment has been conducted—make sense? And could such a setup be housed in a cabinet? Might there be issues with overheating or ventilation? Thanks
Yes. At 6kVA per phase that will get warm in a cabinet. I don’t know what your ambient are but most of my set ups will actually have air conditioning even if ambient is 25° C.
Consumption and peak power are often mixed up. Its important to know duration of peak.
Consumption is measured in kWh. And KW and kVA are. Ot the same thing either power factor is important.(And powe factor when there are peaks)
Always, if possible, build and load test (basic commissioning) before moving to site. Then after install in location -a full site commissioning.
Thank you for the suggestion. Are you referring to hybrid generator systems that combine a diesel generator, battery storage, and a Victron inverter? My intention is actually different: I would like to eliminate short power outages without using a generator whenever possible, by using a battery-based Victron backup system. Could you explain which hybrid generator concept you had in mind?
The Victron system is basically the UPS for the generator to reduce generator use in the hybrid set up.
At your stage of power outages you aren’t expecting extended outages then?
Of course, it’s not for long-term power outages. But what do you think about a solution designed to cover short-term outages of up to 2–3 hours? Some customers can’t install generators because they simply don’t have the space for them. Wouldn’t this be a solution for them?
I know of several systems who also use battery back up only (no solar) to shift their consumption from higher tarriff to lower tariffs times and to peak shave to bring their bills down as they get penalised for that.
What you’re describing—specifically load shifting—doesn’t really make sense in my country.
My actual goals are:
For someone who has a generator: to reduce the generator’s operating hours using this kind of solution.
For someone without a generator: to minimize the risk of power outages.
It might make more sense for smaller, single-phase systems.
What I’m really wondering is whether I’m making a logical error by considering a system like this.
Is there a need?
If yes, and it covers the expectated or potentially expected power outage scenario, then it is a solution.
Because power outages are an expected thing where we live (ranging from a few minutes to several weeks depending on the area). The amount of battery and solar on each system varies greatly from none to cover every available surface, with generator integration sometimes.
Watch out for inductive loads and motor start loads. My system is smaller (3KVA x 3 phase 208/120v). My solution works well, I rely it for daily off grid power on a fishing vessel. BUT Im going to have to install a soft-start for every motor to accomodate the motor spike loads.
A supermarket has heavy inductive loads consisted of Cooling compressors and lighting.
furthermore you have to power routers and switches for the billing system
Leave the generator option open, maybe in the future the grid will get unstable or overloaded by someone´s dream to depend fully on electric (driving, heating or cooling, …) or a local business grows and therefore needs more power which will overload local substations at some times.
so you are save if you keep the addition of components in mind (mounting space, wiring, room for more batteries a.s.o.).
P.S.
Every time you plan or construct an installation, look at it like a single system. You can not compare an installation with another (only if it is Victron or not ). So first regard a new site like a new system (even it may be in the same building). Only it can be part of a larger system you every time have to watch the demands it should be serve, especially it is interconnected with a complete building with also heating, air conditioning and so on.
If you want to add a generator, use Quattro 10k. They have two inputs that can be configured independently. ACin1 without grid code for the gen set and ACin2 with your country’s grid code.
If your peak power demand is significantly higher than your average 18kW, than use the 15k or 20k variants.
Plan a high amperage DC bus bar, fuses and switches.
Plan to add more batteries. If possible I would start with 4 batteries each at 15-16kWh eg current EVE MB31 cells having 314Ah. Why? Batteries might switch off at low voltage / SOC and high current.
As the Victron system will create it’s own micro grid (island) during grid failure, you can add AC- and DC-PV to extent runtime and lower bills - although not requested.
If you want to use a generator definitely go with a Quattro. In theory an ATS can swop the feed to a Mulitplus from grid to generator. But in practice a Multiplus setup for grid input seldom accepts a generator supply.
I’ve been building a small 1-ph battery backup for a single 230 VAC pump based on a Multiplus 48/3000 and 5kWh LFP battery so am doing something similar but far smaller. There will be no PV or generator.
I have all the parts on hand but am still building the panel which will go into a fan-cooled enclosure.
In your case the inrush loads will be distributed randomly over time with each peak representing a small part of the continuous load, a luxury I don’t have. But I can add a soft-starter or install a smaller pump, options you may not find practical.
I’d suggest logging current over a few days if possible to gain some understanding of the pattern.
I think the main point I can add is to make sure the total battery current capability matches the peak loads via the MP2 power conversion .
). So first regard a new site like a new system (even it may be in the same building). Only it can be part of a larger system you every time have to watch the demands it should be serve, especially it is interconnected with a complete building with also heating, air conditioning and so on.