These past couple of weeks I’ve been working on the electrical system. At first I was coming up with really complicated systems but with the help of Matt and Mariah from the Comet Camper I was able to decide what should be incorporated into the system and get the simple structure.
The electrical system was a lot easier than I expected but required more math than I thought. The first thing I needed to figure out was everything I would need if I was going to be using solar panels. Of course I would need the obvious things like the solar panels and the battery but I also needed a charge controller and an inverter. At first I was against using the inverter which converts DC power into AC power because it needed a lot of power to run which made it somewhat inefficient. But I soon learned that if I didn’t have an inverter I would need to get car chargers in order to charge my devices (which would make things difficult), and then I learned I already have an inverter so might as well make use of it. If I incorporated all these elements my system would look something like this….
The energy from the sun will charge the solar panels which will then pass through the charger controller which feeds the solar electricity to the battery. If the battery is ever close to being over filled the charge controller will stop collecting energy from the solar panels or if the battery is even running to low, the charge controller will start collecting more electricity from the solar panels to charge the batteries. From the batteries the DC power will go through the inverter and come out AC power which is then able to charge appliances through a normal plug. Another option would be to use DC power directly from the battery, and use car chargers to charge the appliances.
The next thing I did was decide how many days was I planning to be off grid for so that I could figure out how much electricity would be needed. To do this I made a list of all the appliances I would use and their watts, along with the amount of hours I intended to use them for. I then multiplied each appliances watt by the number of hours they’d be used for and added them together to get the total amount of watt-hours needed for 2 days off grid. I got the total of 2,522 watt-hours but rounded up to 3,000 just to be safe. I then took my 3,000 watt-hours and divided it by 12 volts (each battery=12 volts) so that I could get the amount of amps I would have to fill my battery bank with. Knowing the amount of amps I needed, will come in handy when I need to figure out how many batteries I need to use because each battery only contains a certain amount of amps. The next thing I had to do was to figure out how fast I wanted to charge the batteries using the solar panels. The more watts coming from the solar panel supply meant the faster I could charge the battery bank.
After coming up with the numbers I decided I would need two 250-watt monocrystalline solar panels in order to charge the battery bank in a total of 6 hours and four 75 amp-hours maintenance free batteries (deep cycle battery).
By Amanda Campos