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Newcastle Solar ShopStorage & kit care

Tool · sizer

How much battery do you need?

Tell it what the battery's for and what you'll plug in. It adds up the energy, checks what runs at once and suggests a size class.

What it's for
Your loads

Tick what you'll plug in. Change the watts to match the rating label, and the hours to how long it's on in a day.

3Your suggested size

1kWh class

Your loads use
0 Wh
Stored energy to cover it
0 Wh
Running at once
0 W
Start-up peak to allow for
0 W

Join the list for this size

An estimate, not a promise. It takes 85% of the stored energy as reaching the sockets and suggests the smallest size class that covers a day of your loads. The running-at-once figure adds every ticked load together. Each model's own figures go on its listing.

Why bigger isn't always better

A bigger battery costs more, weighs more and takes longer to refill. If it's only ever half used, you've carried the other half for nothing.

  • Size for the loads you'll really run, with a little to spare.
  • For long power cuts, a way to recharge matters as much as size: a folding panel in the day, or the car.
  • Check continuous output too. Capacity won't help if the unit can't power the appliance at all.
Why does the fridge-freezer show 120W for 8 hours?

Its motor switches on and off. It draws roughly 120W while running and is off for about two-thirds of the day, which averages about 40W, or around 1kWh a day. Change the figures if your label says otherwise.

Can I size a battery for my plug-in solar kit here?

No. A plug-in kit must never be used with a battery, so the sizer doesn't ask about one. It sizes standalone storage only.

Where do I find an appliance's watts?

On its rating label, usually on the back or underneath, or in the manual. A plug-in energy monitor shows what it really draws.