Considering a off-grid or grid-tie with battery backup solar panel or wind power system? Well make sure the batteries you purchase are deep cycle. Lead Acid Batteries are common with renewable energy systems because their upfront cost is lower and they are available worldwide. There are many sizes and capacities of lead acid batteries to meet the needs of your solar panel system but the most important difference is to understand the difference between shallow cycle and deep cycle batteries. Shallow cycle batteries are not meant to be discharged more than 20%, otherwise the lifetime of the battery will be very short, therefore you will have to replace the battery very often and do not make a good choice for a solar power system.
Deep cycle batteries on the other hand are designed to be discharged by as much as 80% of their rated capacity, therefore they are a cost effective fit for a solar panel system because they will last much longer then your typical shallow cycle battery. Letting any type of lead acid battery remained fully discharged for days at a time can permanently damage the battery and can cause a loss of charging capacity. Therefore if you are considering a system with batteries, be prepared to maintain and keep an eye on the battery bank to make sure its being charged. With proper care deep cycle lead acid batteries will have a long service life and will be compatible with most power generation systems such as solar panels or wind turbines although with poor treatment and lack of maintenance the battery life will be very short.
Many customers who have electric service want to go “off-grid” but don’t really understand what they are getting themselves into when working with batteries. Off-grid solar and wind power systems should be used in areas where there is no access to electric service. If you currently have electrical service at your home or small business you are better off purchasing a grid tie solar power system or a grid tie wind turbine. Grid-connected systems often break even faster and require less maintenance because these types of systems require no batteries.
Any extra energy produced is stored right into the gird and the utility gives you credit for future use of that electricity. Potentially you can develop a system that can offset 100% of your yearly electrical usage, basically zero out the amount you are charged for electricity consumption. Connecting your system to the utility gird is called “Net-Metering”. If your considering a small battery for backup power, you might want to consider the Xantrex Xpower 1500, which deep cycle battery with a built in inverter, it can help you get started with backup power safely and for a low upfront cost.