Solar power for a shed or workshop

"Solar panels for a shed" covers two completely different products that get sold as if they were the same thing. Work out which one you actually want before you spend anything — the wrong choice is an expensive disappointment.

Two products, two jobs

Off-grid 12V shed kits

A small panel, a charge controller, a leisure battery and usually a modest inverter. No mains connection anywhere. It suits a shed at the bottom of a garden with no supply and never likely to get one: LED lighting, charging cordless tool batteries and a phone, a radio, a small fan, maybe a security camera. Typical budget runs from under a hundred pounds for lighting only up to several hundred for a battery bank that will run something useful.

What it will not do is run mains power tools. A 100W panel and a 100Ah battery has nowhere near the instantaneous capability of a circular saw, and the cheap inverters bundled with these kits will trip or overheat when you try.

Mains plug-in solar devices

Panels plus a microinverter with a standard plug. It has no battery and it cannot work without a live mains supply — if the grid goes down, it shuts off automatically. Instead of powering the shed in isolation, it feeds up to 800VA into your household circuits, and whatever is drawing power at that moment uses it first. See how plug-in solar works.

What a workshop actually draws

• LED strip lighting: 30–100W. Trivial, and the easiest thing solar covers.
• Cordless tool chargers: 50–100W each while charging. A good match for daytime generation.
• Bench grinder, sander, router: 400–1,200W in short bursts.
• Table saw or planer thicknesser: 1,500–2,500W, with a heavier startup surge.
• Dust extractor: 750–1,500W, and it runs whenever the machine does — often the second-biggest consumer in the room.
• Compressor: 1,000–2,000W while the tank fills, then idle.
• Heating: 1,000–2,500W, and the largest annual cost in an uninsulated workshop.

The shape of that list matters. Workshop loads are spiky: nothing for ten minutes, then 2kW for ninety seconds. A plug-in device smooths the background — lighting, chargers, extraction fans between cuts, a fridge if you keep one out there — and contributes its full 800VA towards the spikes, with the grid making up the rest automatically. You never have to manage that; it happens on its own.

What a plug-in kit realistically covers

A weekend woodworker with a well-lit workshop, a couple of chargers on the bench and an extractor firing intermittently is drawing a few hundred watts on average across a Saturday afternoon. On a decent spring or summer day, that is comfortably inside what an 800VA device generates, so a large share of the session runs on your own electricity.

Where it does not stretch is heating in winter and sustained heavy machining. A 2kW heater alone exceeds the device's entire output, and running a thicknesser with extraction can pull 4kW between them. The solar contribution is real but partial — it caps out at 800VA no matter what you plug in.

Mounting on a shed

• Most garden sheds are light timber structures. Check the roof can genuinely carry framed panels and the wind load before fixing anything to it — a felt roof on thin battens usually cannot.
• A ground-mounted A-frame beside the shed avoids the structural question completely and is easier to angle towards the sun.
• Watch shading from trees and fences. Workshops tend to be tucked into the least sunny corner of a garden, which is precisely the wrong place for panels.
• Route cabling so it cannot be caught by a mower, a wheelbarrow or a door, and use an outdoor-rated socket for any outside connection.

The rules that apply

A plug-in device in Great Britain must be a product listed as Compliant on the ENA Connect Direct register, must stay within 800VA AC, 3.5A and 2,000Wp of panels, must be battery-free and must plug directly into a socket outlet — no extension leads, however tempting that is at the bottom of a garden. Only one device is permitted per household, and you register it after installation. Full detail in rules and limits and registration.

If the cable will not reach a socket, the answer is to reposition the panels or have an electrician fit a socket in a better place. It is never to add an extension lead — see the installation guide.

Choosing between them

• No mains at the shed, lighting and charging only: off-grid 12V kit.
• No mains, but you want to run real tools: get a supply installed. No solar product changes this.
• Mains already there and you want a lower bill: plug-in solar.
• You want power during a blackout: neither — plug-in devices shut down, and off-grid kits are too small for tools.