What Type of Home Solar Power Battery Do I Need?
Solar power can free your home from the electric grid - it doesn’t get any more revolutionary than that. Solar provides any family the potential for complete energy independence. Most home solar power systems in use today are grid-tied with backup electricity coming from the grid during the night.
To achieve off-grid freedom, systems require an in-home source of backup electricity provided by a battery bank. This group of batteries charges up from solar energy collected during the day, and releases it at night when direct solar electricity is unavailable. Present battery technology offers a few different choices for type of home solar power battery.
Car or Cart?
Many homeowners’ first inclination is to purchase a car battery, a common and inexpensive choice to be sure, but not the proper battery for home solar power. Car batteries are made to discharge a lot of electricity at once (i.e. to start a car) and then slowly recharge over time as the car runs. Such batteries would not last very long in a solar power system.
The most common batteries used in solar system battery banks are actually golf cart batteries. Golf cart batteries are designed to discharge slowly over several hours during the day and then recharge quickly at night. Home solar systems require a similar charge cycle. At night, the batteries need to slowly discharge power into the home and then recharge rather quickly during the day.
So, golf cart batteries combine affordability with longevity (2-4 years) much better than car batteries. However, cart batteries are typically 6-volt batteries, and most home solar systems work in 12, 24 or 48 volts. So the batteries will have to be wired in series to reach the correct voltage, and then parallel to complete the battery bank.
Forklift batteries are excellent for home solar power systems, but are more rare and expensive than golf cart batteries. If you can find and afford them, they’re definitely worthwhile.
Deep-Cycle, Lead-Acid, Gel Cell
With battery technology on the cusp of rapid advancement, conventional lead-acid batteries are your best choice for now. Deep-cycle flooded Lead-acid batteries are specifically what you’re looking for. As aforementioned, preferably out of a golf cart or forklift.
Note that you don’t want your batteries to discharge more than 50% of their capacity - you need a battery bank that stores more than twice as much electricity than your home uses on any given night. There are methods for calculating how many batteries your home solar power system requires.
Lead-acid batteries usually require some maintenance, including filling up with water. Gel cell batteries, however, are sealed and require no maintenance. They also emit no gases and are safer to place in the garage or basement. Like golf cart batteries, gel-cells can last up to four years with moderate discharging and price competitively as well. A special charger is required.
These suggestions apply more for the DIY solar homeowner trying to piece together some home solar power. Battery banks are also available through many solar system installers, which may cost more, but are new, warranted, professionally installed and likely closer to the cutting edge of efficiency and battery life. Find out how much a battery bank for your home solar power system will cost from an experienced professional.
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