Solar power for a garden office

List each appliance, its running power and how long it will be used. Multiply watts by hours to get watt-hours. A 50 W laptop used for six hours consumes 300 Wh. Add every appliance to estimate one day's energy before allowing for conversion losses and poor solar weather.

Solar panel wattage

The panel's rated output under test conditions. Real output varies with sunlight, temperature, angle and shade.

Battery capacity

Stored energy, normally stated in Wh. Not all stated capacity will necessarily be available at the AC sockets.

Inverter output

The maximum AC load the system can supply, including any start-up surge allowed by the manufacturer.

Daily energy use

The total Wh used over a day. This determines how much storage and solar recharge the office needs.

These examples are planning assumptions, not product specifications or guaranteed performance. Check every appliance rating plate and allow for inverter losses and less productive winter days.

A battery should not be selected by matching its headline Wh figure exactly to the table. Allow for usable capacity, conversion losses, battery reserve and the number of low-sun days you want to tolerate. For a desktop or gaming setup, use the solar-powered computer guide and calculator to check the PC, display and peak workload together.

A 1,500 W resistance heater used for two hours consumes 3,000 Wh—more than four times the everyday-office example. A 2,000 W kettle running for six minutes uses about 200 Wh and also requires an inverter able to supply roughly 2,000 W at that moment. Large saws, compressors and pumps may draw a substantial start-up surge as well as a high running load.

Solar can make a useful contribution to comfort, but direct electric heating is often a poor match for a small off-grid system because heat demand is highest during the least productive solar months. Improve insulation and draught control first, and treat any electric heating load as a separate sizing decision.

Put panels where they receive consistent light without shade from the office, fences or trees. A south-facing position normally maximises total generation, while east or west can better match morning or afternoon work. Shading can matter more than nominal panel wattage.

Panel ratings are not a promise of continuous output. Short winter days, low sun and poor weather can leave an office dependent on stored energy or another charging source. Use the main UK solar calculator for broad solar-output context, but do not treat its grid-connected savings model as an off-grid battery-sizing result.

1. Measure or read the rating plate for each intended appliance.
2. Calculate normal daily Wh and the highest simultaneous watt load.
3. Decide how many low-sun days the battery should cover.
4. Check panel input, battery limits and inverter output in the manufacturer's instructions.
5. Keep fixed sockets and wiring outside a DIY portable-power plan.

Compare the component approach in the off-grid shed solar kit guide with the simpler all-in-one route in the garden-office power station guide.

• Never connect a portable power station or off-grid inverter to a household socket or fixed circuit.
• Use a competent electrician for fixed sockets, lighting circuits, earthing or a mains supply to an outbuilding.
• Use equipment only within its manufacturer-stated temperature, ventilation, moisture and load limits.
• Keep cables protected from water, sharp edges, doors and trip damage; stop using damaged plugs, leads or equipment.
• Do not cover a power station while charging or operating, and do not use a swollen, damaged, unusually hot or recalled battery.
• For workshop loads, check that the supply can support both running and start-up demand.

The UK plug-in solar legal guide covers the separate position for systems connected to the household electricity supply.