Battery to augment grid supply?

Looking for some technical advice please.
We have bought a farm in UK, off grid but are bringing in a single phase 220V supply across 600m of farmland. To supply 100A may require very expensive 250mm2 cable. If we use a cheaper cable which only delivers 60A is there any way to meet short duration peak loads of 100A using batteries? (I imagine combining AC is not easy).
Any suggestions welcome, thanks.

Good question @rogereabc, and welcome.

What are you using the 100A for, and how long is a “short duration”?

What is the additional cost that you are looking at? Would you consider a generator, or prefer solar?

By ‘AC’ do you mean Aircon, or AC electricity?


Thx Marty,
Peak loads for cooking, 2 - 3 hours.
Additional cost is >£10k for 250mm2 cable over 150mm2
No wish for generator or solar at this stage.
Combining AC means two alternating current electrical sources, grid & inverter - I don’t want to switch between them, I want the inverter to supplement the grid supply in order to meet the peak loads described.

You wouldn’t need to switch between them with the right gear. I think it’s possible, but @Svarky is your man.

Hi @rogereabc

What you are referring to is technically known as peak lopping. When peak demand is very high and grid supply is limited then batteries and an inverter can make up the short fall.

There are several powerful multi-mode inverters which can do this including Schneider Conext XW+, Victron Quattro and the Selectronic SP PRO. (One inverter is used per phase and they are synced)
Note you don’t need to use solar with any of these as the battery can be charged in set time intervals. However, it usually makes sense to top up & charge using solar.

Thank you, that’s very useful.