(DC) Direct Current  
and (AC) Alternating Current and Solar Energy

(DC) Direct Current

Batteries and solar cells only produce  (DC) Direct Current. Batteries can only be charged with direct current. How fortunate that batteries can only be charged with Direct Current since that’s all solar panels can produce! With DC (Direct Current), the movement of electricity travels in only one direction between the positive and negative. DC is found in all kinds of low voltage applications, especially where something is powered by batteries. If you were drawing Direct Current (like showing a frequency) it would look like a straight line.


(AC) Alternating Current

AC (Alternating Current) on the other hand alternates direction back and forth at a rate in the U.S., for example, of 60 times a second. Alternating Current (AC) is the form of electricity that is delivered to homes and businesses. The power available from a standard wall socket in the U.S. is 120 volts, 60 cycle (60HZ, 60 times back and forth a second), AC electrical energy. (In Europe that cycle is 50 times per second which is why your U.S. hair dryer will not fare well plugged into a European wall socket!) U.S. power companies are set up to deliver and appliances/devices are set up to operate on 120 volt, 60HZ, AC current. There are exceptions like your washer and dryer. They probably run on 220 volts.


AC became the current of choice because a great many devices we use need more power to operate than Direct Current (DC) can provide. Also, your power company can deliver it over long distances cost effectively using transformers to change the voltage both higher and lower. They can’t do the same thing with Direct Current.


If you were to draw Alternating Current the line would look like a smooth even wave moving forward up and down.


Access to Both Direct & Alternating Current

You are not the power company. Your system is not producing Alternating Current. You have a solar panel(s) producing Direct Current from sunlight charging a 12 volt deep cycle battery that can only accept and produce the same, Direct Current.  


Many things run on Direct Current (DC), especially when you get into that whole camping and recreational area; fans, lights, all sorts of things. These DC devices can connect directly to the battery (using the often provided proper wiring). These appliances/devices are built specifically to operate on DC. The receptacle for 12 volt systems looks like the cigarette-lighter type plug (or power port) in your car. Many trailers for instance come equipped with a plug of this sort. This type of plug can also be purchased. So, you can use a DC device directly with your battery if you want.  

   

But, maybe you’d like to use some devices that don’t have that little end that plugs into a cigarette lighter type socket. Or, perhaps an alternative AC adapter came with your device. Or, perhaps you’d like to use more elaborate devices that plug into regular wall outlets at home, devices that need more power to operate properly, devices that run on standard AC electricity. Then you need a power inverter.




DC, AC, INVERTERS FOR SOLAR ELECTRICAL USE

THE “OUTPUT” SIDE OF YOUR SOLAR ENERGY SYSTEM.


Solar panels and charge controllers are basic major components involved in getting energy/electricity in to a battery.


DC current, AC current and something called a Power Inverter are issues and components involved in getting energy/electricity out of a battery to use.   

Inverters and Solar Energy 2