Solar Energy:

A Guide to Understanding Solar Batteries

Adding battery storage to your solar installation can be a great way to improve your quality life at home or own the road by ensuring you have reliable access to power, saving thousands on monthly utility bills, becoming energy independent, and living a green lifestyle. And like everything else in solar installations, there is a lot to consider when deciding on a solar storage option.

Deep cycle batteries are the best solution for battery storage. They look similar to car batteries, but are actually very different. In contrast to car batteries which only provide short bursts of energy, deep cycle batteries are designed to provide sustained energy over a longer period of time. Renogy offers a variety of deep cycle batteries for purchase, from flooded lead acid to lithium batteries.

In this guide, we’ll answer big questions around how much energy storage you need, what makes different batteries unique, and what to look for when shopping for batteries for your solar installation.

How much energy storage do you need?

Solar batteries store the energy that is collected from your solar panels. The higher your battery’s capacity, the more solar energy it can store. In order to use batteries as part of your solar installation, you need solar panels, a charge controller, and an inverter.

Properly sizing your battery bank is a crucial step to creating an efficient and powerful system. If your battery bank is undersized, you may not be able to fully meet your energy needs. If your battery bank is oversized, your solar panels may not be able to fully recharge the batteries, which may lead to chronic undercharging, decreased lifespan, and poor performance. Deep cycle batteries can be discharged up to 80%, but most manufacturers recommend not discharging below 45%. Regularly going beyond that point will shorten the life of the battery.

Properly sizing your battery storage is crucial to ensuring you have a long-lasting, safe, and efficient system. In short, we typically recommend calculating your energy needs (the Renogy solar calculator does just that), and then going from there. In this section we talk about the different tools and tips and to use when sizing the solar storage system in your installation.

What to consider when selecting a solar storage solution

When shopping for battery storage for your solar installation, there’s a few main options to consider: flooded lead acid, sealed lead acid, and lithium batteries. Considering the price, capacity, voltage, and cycle life of each of those options will help you decide which is the best for you.

Price: Batteries can vary from around $100 for the cheapest lead acid battery to more than $1,500 for a lithium iron battery. Also, be sure to consider the ultimate lifetime and not just upfront costs.

Capacity: Battery capacity is important because it measures the amount of energy you can store. If you need to power certain appliances for long periods of time, you'll need more batteries to carry a bigger load.

Voltage: Be sure to check the voltage of the battery bank to ensure it is compatible with your panels and the rest of the system, particularly your solar panels. Panels typically come in either 12V and 24V options.

Cycle Life: This specifies the number of discharge and charge cycles a battery can provide before the capacity drops below the rated capacity.

Check out the following posts in this section to learn more about where different technologies rank in the above categories and what makes different batteries unique. Additionally, once you purchase those batteries, how do you install the batteries in your system?

Solar batteries at Renogy

Renogy offers a range of sealed lead acid and lithium batteries for sale.

Contrary to flooded lead acid batteries, sealed lead acid batteries require little to no maintenance and are spill-proof. They are more expensive than flooded lead acid batteries, but also have a much longer cycle life. Within the family of sealed lead acid batteries are two types: gel and AGM batteries.

Gel batteries, which use silica to stiffen the electrolyte solution in the battery, tend to have lower charger rates and output than absorbed glass matt batteries. They also can’t handle as much current, meaning they take longer to recharge. However, gel batteries have a greater lifespan than AGM batteries and can be mounted in any orientation. Absorbed glass matt batteries offer a better temperature range and are a bit cheaper than gel batteries.

Lithium iron phosphate batteries are the most expensive battery option, but they have an extremely long cycle life, high discharge and recharge rates, and are incredibly compact and lightweight. They also require little to no maintenance. Learn more about all of Renogy’s offerings below.

Closing / recap

As deep cycle batteries continue to improve in efficiency and drop in price, there’s never been a better time to add storage to your system. Solar battery storage is great for those living a mobile lifestyle on the road or remotely in an area without reliable access to the electrical grid. Solar panels and batteries can take the place of a noisy and dirty gas-powered generator. Additionally if you’d like to be able to run your solar panels in case of grid outages, battery storage is a great way to ensure continued energy access.

Renogy has a range of deep cycle batteries available for purchase, including the highly efficient but expensive lithium batteries and sealed lead acid batteries, which are more efficient than flooded lead acid batteries and cheaper than lithium iron phosphate batteries.

Battery storage doesn’t have to be overly complicated. Review the above posts and you should be well equipped to start storing all that energy collected from your panels in no time.