Solar Chargers

Solar Panels Kits

Useful Solar Information

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How do I choose a solar panel?

There are three things to consider in order to choose a Solar panel or create a Solar system.

You need to know how much energy your battery can store, How much the device you want to power draws and how long it will be run for, then select a Solar panel that can replenish your ‘stock’ of energy in the battery in line with your pattern of use.

Please Note, this is a rough guide as we have estimated the wattage of the devices, to be accurate you will have to either do the calculations yourself (see below), or enter the specific wattage for your device.

We hope the calculator below helps you out!

Solar Power Calculator


Device to Add Running Time  
Something Else? Watts x Hours  

Use the Calculator above to add stuff to your calculation, this will tell you what you need here!

Choosing a Solar Panel

You will need to make sure that you have enough battery power as well as solar power, You may need multiple batteries (enough to cover the Amps per hour draw (Ah)) and multiple panels (a 160watt solar panel is the same as 2x 80watt solar panels)

If you are planning a big system I would suggest sepaking to an expert for your particular situation, remember this is a guide, different panels have different performance, and batteries are different as well!

For those of you interested this is how we worked it out!

1. How Much Power can you store?

Battery capacity is measured in Amp Hours (eg 17AH). You need to convert this to Watt Hours by multiplying the AH figure by the battery voltage (eg 12V).

For a 17AH, 12V battery the Watt Hours figure is 17 x 12 = 204WH

This means the battery could supply 204W for 1 hour, or 102W for 2 hours i.e. the more energy you take, the faster the battery discharges.

2. How much energy will your appliance(s) use over a period of time?

The power consumption of appliances is given in Watts (eg 21" fluorescent light, 13W). To calculate the energy you will use over time, just multiply the power consumption by the hours of use.

The 13W light fitting, on for 2 hours, will take 13 x 2 = 26WH from the battery.

Repeat this for all the appliances you wish to use, then add the results to establish total consumption.

3. How much energy can a Solar panel generate over a period of time?

The power generation rating of a Solar panel is also given in Watts (eg 10W). To calculate the energy it can supply to the battery, multiply Watts by the hours exposed to sunshine, then multiply the result by 0.85 (this factor allows for natural system losses).

For the Solar 10W panel in 4 hours* of sunshine, 10 x 4 x 0.85 = 34WH. This is the amount of energy the Solar panel can supply to the battery.