As a designer and installer of solar PV grid-tied systems, I am often asked about going off-grid with battery backup.  Seems the economy has people wondering about long term survival on their own terms.

When you buy a modern grid-tied solar PV energy system, you are tied directly to the grid, which both provides your power as well as consumes the power your solar system makes.  What you DO NOT have in a gird-tied system is continuous power from your solar arrays if the grid goes down.

If you want to maintain power when the electric company has lost power, then you need to have some form of storage system, such as batteries, to carry the load when the grid goes off line.

A grid tied solar electric system is pretty simple; modules connected via a converter to the meter, and onto the grid. Want battery backup? Now you need to have batteries and a charge controller, so that the system can switch between charin the batteries and draining the batteries, without your ocmputer crashing in the house when the grid goes down.

If you own a cell phone, an ipod or any other electronic device that depends on a battery, you know that battery maintenance is a nightmare.  How long does your cell phone last? Probably not the 20+ years expected life of a solar electric system.  Even the batteries for a solar system should be designed to last for 10 years or longer. And tihs is not your typical battery use.  You may goes years without needing them at all, or have to use them once or twice a year for a couple hours at most.

Once the grid goes away, now those batteries become your life blood. You have to make sure they stay charged, and that you do not discharge tehm too deeply. As they are used more and cycled more often, you will need to overcharge them, equalize the lines, keep the acid levels right, the list goes on and on.

So, how do you determine what a battery needs for maintenance, and how long it will last? It has to do with cycles, or how many times you used the battery. Most solar batteries are considered deep cycle, meaning they can hold a big charge, but you only want to use about 30% of the power in them, so they will last longer. As you recharge them, you want to make sure ALL the batteries in the string are getting the same charge.

Size and number of batteries, cable lengths and how the batteries are connected will also affect battery life in solar systems.  Nth Degree Solar Energy can help you find the right batteries for your application.  Call today: +1-970-241-1376 or visit our website at http://NthDegreeEnergy.com/