Solar energy systems offer many wonderful qualities including long life spans and very low operating costs after the initial purchase cost. However it is also important to understand how they work in terms of energy storage and use which is quite different to mains electricity supply.
At the heart of a solar system is the battery. This stores the energy from the solar panel during the day and releases it when required (often at night). A battery’s storage capacity is in Amp hours (Ah). So for example a 10Ah battery can supply 10 Amps for 1 hour or 1 Ampfor 10 hours.
The power from a battery is in Watt hours (Wh). This is the Amp hours (Ah) x Voltage (V). Our battery systems are 12V. Therefore our 10Ah battery at 12V would have 120Wh.
Batteries decline in capacity each time you charge them up and then use them. To extend the life of a battery as long as possible it is not discharged more than 50%. This means our 10Ah battery has 5 Ah available for our use which = 60Wh.
Where labeled in the system specifications this is the energy availability of the system daily. If a product i.e. TV uses 30W, for one hour it will have used 30Wh. To watch the TV for 4 hours a day you will need 120Wh daily.
The amount of Wh the system generates a day allows you to work out how many different things you can power off it. E.g.
Laptop = 30W power consumption
TV = 30-100w
Mobile Phone = 5W
Fridge (A+ efficiency) = 25W (but for 24 hours as always on)
Multiply power consumption x hours of use to get Watt Hours (Wh). E.g.
A 30W TV used for 2 hours a day will use 60 Wh of power.
A 25W Fridge used for 24 hours a day will use 600 Wh of power.
5 x 5W lightbulbs used for 4 hours a day will use 100Wh of power
Always make sure you know how much power each device uses and how long it will be run for so that you pick a solar system large enough for the requirements. Our engineers can advise you on the size and layout of your preferred system.
Lumens are a measurement of a light’s brightness. As a reference a normal 60W lightbulb puts out 800 lumens. The lumens for each solar system are recorded in the specifications to give a comparison of the different systems in brightness terms. 600 lumens work well for lighting a good size room, if you want to light up multiple rooms or a large hall you will need more than this.