Solar Technology

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

1 : How much energy can your battery store?

Battery capacity is measured in Amp Hours (e.g. 17AH). You need to convert this to Watt Hours by multiplying the AH figure by the battery voltage (e.g. 12V).  this is just the simple calculation below

  •  X (Battery size in AH) x Y (Battery Voltage) = Z (Power available in watt hours

  • For a 20AH, 12V battery the Watt Hours figure is 20(X) x 12(Y) = 240 WH (Z)

Q. Are car battery’s just as good for solar as leisure battery’s?

A. The answer to this is no they are not. The reason is because a leisure battery has been designed to be discharged and recharge, a Car battery is designed to provide a lot of power quickly but it’s not able to cope with a low internal charge and recover fully.

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

The power consumption of appliances is generally given in Watts (e.g. A small portable TV is around 20W this information can be found on the data sticker that most electrical items have). To calculate the energy you will use over time, just multiply the power consumption by the hours of intended use.

The 20W TV in this example, on for 2 hours, will take 20 x 2 = 40WH from the battery.

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

 Water pump (20w) on for 5 mins per day   = 1.665w per day
Compressor fridge full not empty 40W on for 12h per day = 480w per day
All LED lights 10w on for 5h per day   = 50w per day
Total watts per day = 531.665w            

An easy way to lower your power usage is to turn your fridge on the lowest setting, keep it full and with the door shut this will help you use 80% less energy. 

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

The final part to sizing your solar system is the solar panels. The power generation rating of a Solar panel is also given in Watts (at CCCAMPER we like to fit a 100W solar panel). In Theory, to calculate the energy it can supply to the battery, you multiply Watts (of the solar panel) by the hours exposed to sunshine.

In practice it’s not a great way to calculate the output from a solar panel so we work to a few simple rules.

  • We would generally advise that an average UK winters day will only give you 1 hours sunshine
  • An average UK summers days will give you 6 hours of sunshine.

So in winter a 10w panel will provide 100w worth of energy back into your battery. (100w x 1 = 100w)

In Summer a 100w panel will provide 600w worth of energy back into your battery. (100w x 6 = 600w)

Using the above calculation takes into consideration any losses in the system from the regulator, cables and battery you may be using.

4 : Putting it all together to size your system.

Knowing your power requirements and the time of year you want to use the system is vital to this step.  We will use the example above with a power requirement of  196w per day.

If this is the requirements for late spring to early Autumn use we could use this equation

Watts required / time of year sunshine hours = panel size        
           531.665 / 6 = 88.61083333333333W panel

As we don’t make a 88.61083333333333w solar panel we would recommend looking at a 100w solar panel for this application.

However if this was an all year requirement i.e. also needed in the UK’s winter the numbers would change

Watts required / time of year sunshine hours = panel size        
           531.665 / 1 = 531.665W panel

As we don’t make a 531.665w solar panel we would recommend looking at 4 x 150w solar panels for this application. Or simply fit one of CCCAMPERS 240v power distribution units for winter months.

The final Piece 

The final Piece to complete your solar system is the Charge Controller or Voltage Regulator. Its basically the same thing just a different name. This essential piece of your solar system controls the Charge put into your battery, stops overcharging and prevents the solar panel pulling power from the battery at night. 

We hope this Guide has helped you understand the sizing of a simple solar panel setup. If you have any other questions regarding sizing a system for your requirements please give us a call on 0333 456 3345