There are many solar batteries available – how do you know which one is best for you? Some important aspects to consider when selecting a solar battery include cost, capacity, power, round-trip efficiency, degradation rate, and warranty. All of these aspects plus more are considered in each solar battery’s quality rating.
How solar batteries work
The primary function of a solar battery
is to store energy produced by solar panels. that can be drawn on at a later time. Storing energy for later use provides many bonuses, from financial benefits to being a backup source of power in the event of a grid outage.
The main advantage of installing a solar plus storage energy system is that it gives you the ability to use solar electricity even when the sun isn’t shining. When you install a solar panel system without a battery, excess electricity that your system generates is sent back to the grid. With a solar battery, that energy can be stored and drawn on when the sun goes down, and you’ll only need to draw and pay for energy from the grid when your battery is depleted.
To learn more about how solar batteries work, check out our section on solar battery systems.
How to compare solar batteries
There are many ways to compare solar batteries. Here are a few key metrics to keep in mind:
Capacity & power
A battery’s capacity is the total amount of electricity it can store measured in kilowatt-hours (kWh). A battery’s power tells you the amount of electricity that it can deliver at one point in time measured in kilowatts (kW). It is important to consider both capacity and power when evaluating solar batteries. A battery with high capacity but low power can only provide a small amount of electricity at one time but can store enough energy to keep providing that electricity for long periods of time. On the flip side, a battery with low capacity but high power may be able to power many appliances or your entire home at one time, but potentially only for a few hours due to its low capacity.
Just like solar panels, solar batteries have efficiencies associated with them. A battery’s round-trip efficiency represents how much energy can be used as a percentage of the amount of energy that it took to store it in the first place. Batteries experience efficiency losses during the conversion of energy from storage to usable electricity, typically about 5 percent.
Battery life and warranty
Like cell phone batteries, solar batteries naturally degrade over time and will hold less overall charge the more you use them. Solar battery warranties are usually measured in cycles or years and guarantee the ability to hold a certain level of charge by the end of the specified warranty term.