Popular Solar Batteries And Their Recommended Uses

There are various types of solar batteries available and many people don’t understand the differences between them. Some solar battery banks contain wet cells or lead acid batteries such as batteries for golf carts, some use sealed gel batteries and others have absorbed glass mat (AGM) batteries. Each of these types of batteries has different venting, storage temperature and mounting demands. We will discuss these various types of solar batteries and their recommended uses in more detail below.

Every battery that is made is specifically designed to handle the charging and discharging cycle of the application it is used for. Take regular car batteries for example; they are made to handle a high discharge in a very short time and then an extended period of gradual recharging. They won’t work very well in a solar battery bank because of the discharge and recharge cycle they possess. Solar banks need batteries that are designed for a much longer discharge time such as all night and then a total recharge in only a few short hours during the day.

Deep Cycle Marine And RV Batteries

Deep cycle batteries that are designed for marine and RV use have been used in home solar banks, but they only work for very small systems. They just don’t seem to have the capacity needed for the continuous discharging and recharging cycles needed for the home setup. They have been known to overcharge in the home solar setup and gradually evaporate the electrolyte causing the internal plates to oxidize and possibly short. Most experts don’t recommend using marine or RV deep cycle batteries for this reason.

6-Volt Golf Cart Batteries

The most popular type of battery used in solar battery banks is by far the 6-volt wet cell lead acid golf cart battery. These are designed for the purpose of handling a heavy continuous discharge from usage and then recharging quickly in only a few hours. This is one of the few batteries that can accommodate this type of discharging and recharging cycle daily. It is also the most affordable choice and can easily be purchased at your local battery center.

One thing to keep in mind when using wet cell lead acid batteries is that they will gas out when they are recharged. For this reason, they should not be installed in a battery bank that is located indoors because the gas produced is very explosive. If they are used in an enclosed battery bank structure, the box must be ventilated to the outside to prevent build up of the gases. The battery enclosure should also be insulated to keep the batteries at a constant temperature between fifty and eighty degrees F to prevent voltage drop.

Sealed Gel Batteries

Sealed gel batteries are a better choice over wet cell acid batteries as they will not gas out when they are recharged. They don’t need to be ventilated as a result and are able to be used in an indoor solar battery bank. When they are installed indoors, they remain at a consistent ambient temperature which allows them to operate at peak performance levels. They do not require periodic refilling like wet cell batteries, nor do they need the terminals checked for corrosion or cleaned because of it.

Sealed Absorbed Glass Mat Batteries

The best choice of battery type for your residential solar battery bank is the absorbed glass mat battery or AGM battery. They are also sealed batteries making them spill proof and do not require refilling over time. They have some of the same characteristics as the gel battery as they will not gas out when recharged either. For this reason, this too is a perfect candidate for installation indoors for your solar battery bank.

The AGM batteries are said to be superior to the gel batteries in that they are able to hold their charge better, are better quality, have a lot slower self discharge time and seem to last longer. Its performance is unmatched by the other types of batteries making it the superior choice for solar battery banks. This is also the battery of choice for applications such as hospitals, most airplanes and remote cell phone tower installs. This is also the most expensive choice of battery for this usage, but the exceptional performance seems to be worth the extra cost.

Battery Conditions

With each of these types of batteries, ambient temperature and relative humidity play an important part in the battery performance. When the temperature drops drastically or there is an extreme swing in the temperature, batteries can lose up to half of their charge. Like it was said earlier, if your batteries must be stored in an outside enclosure like the wet cell batteries, then the enclosure must be insulated to prevent extreme temperature changes. This is where the sealed gel and AGM batteries have the advantage because they can be installed indoors in a constant ambient temperature.

To get the most life out of your batteries, many experts recommend keeping your voltage drop around 30 percent and then recharging again. This 70 percent charge range will help them to last longer because they don’t get too deeply discharged at one time. Some refer to this as shallow cycling of the battery and helps to make them last as long as possible. It doesn’t hurt the batteries to occasionally do a deep discharge down to 20 percent charged, but it is not recommended you do this very often.

Now that you have learned about the various types of solar batteries available, you can make a more informed decision on which type will work best for you. You can choose between wet cell lead acid 6-volt golf cart batteries, sealed gel batteries and absorbed glass mat (AGM) batteries. They all have their pros and cons as far as price and possible installation locations to keep in mind. Whichever solar battery type you choose will get you that much closer to your independence from the ever increasing utility rates.