DEEP CYCLE BATTERIES
Ok..if you’re reading this article you either already have a home solar power system in place or you are seriously considering one. Am I close?. Well at any rate, the subject of deep cycle batteries is important to learn about because as you know, solar panel systems only generate electricity during the day. The other fact is that in many cases the electricity generated during the day isn’t all used up, so instead of the electricity dissipating in the form of heat from your system, why not store it and make it available any time?
Ok, I know you know where I’m going with this, so let’s jump into the world of deep cycle batteries and learn a bit more.
DEEP CYCLE BATTERY BASICS
To start, lets get real basic and talk about what a battery actually is on a piece by piece level. For a really simple, non scientific definition, a battery is basically a system, unit, device, etc that stores energy (potential energy) for later use. Remember back in 7th grade Science class when you learned about how a taut rubber band is storing potential energy and then if it’s released, the actual motion of the rubber band is called kinetic energy? No? Me neither, was usually making paper airplanes in Science class, but I learned that somewhere. Well a battery works similarly and is based on the conversion of chemical energy in to electricity. This is done through what’s called a galvanic cell. A galvanic cell is a device that is made up of 2 electrodes, each a different metal, surrounded by an electrolyte (i.e. battery acid). The actual definition of a battery is 2 or more of these cells interconnected, but quite often a single cell is also referred to as a battery; similar to your common D, C, AA, AAA type batteries.
Now just to clarify, batteries don’t actually MAKE electricity. Again, they are a device that simply stores and electrical charge. Now this electrical charge can be stored long term and then released; either all at once or at different times. With rechargeable units, like deep cycle batteries, the charge and discharge process can be repeated over and over. The charge and discharge function is not 100% efficient. There is always some energy lost in the form of heat that is produced from the actual charge and discharge process.
In the case of deep cycle batteries, they are designed to be charged and discharged all the way down to a charge level of 20% time after time with no change in performance. Now when comparing a deep cycle battery with others conventional batteries, the main difference is the plate design. In deep cycle batteries the plates are solid lead, rather than a “sponge” type design in other batteries. The solid plate setup is a great design for supplying continuous power to a load where there are no major spikes or heavy draws of power.
HOW MANY WILL I NEED?
Finally, when considering a deep cycle battery set up as a back up system for your home solar power system, you must of course have an idea of your home’s energy needs on a daily basis as well as an average daily output that your system produces. You not only want to be sure you’re storing all the excess power, but in the case of stormy days or night hours, you want to be able to adequately supply your home. These figures are typically determined in the planning stages of a solar power system before any construction. Most of the home solar power guides that are reviewed on this site discuss ways of obtaining discount deep cycle batteries and give tips on integrating them into your system.