When you put together a solar energy system, you basically have three options when it comes to how your batteries work. Flooded lead-acid (FLA) batteries and sealed lead-acid batteries both use lead-acid, and while the former requires regular maintenance, the latter does not. The other popular option is lithium, which functions very differently.
Many of the leading solar energy system providers use lithium batteries, and these have become the preferred type of batteries for many reasons.
Lithium Batteries Are More Efficient
One of the biggest advantages of lithium batteries is that they are more efficient, and when you’re talking about energy systems for the home, efficiency is always a top concern.
Lead batteries are only 80% to 85% efficient in their best condition, which means you only get to use 85% of the solar that’s coming into your system, the rest of which is lost in the charging and discharging process. On the other hand, lithium batteries are 95% efficient, which means you are only losing 5% of power.
Higher efficiency also means that your batteries charge faster, which could actually save you money in other areas of your energy system.
Lithium Batteries Have a Faster Charge Rate
Greater efficiency means faster charge rates, but why? Lithium solar batteries can handle higher amperage from the charger, so they will refill faster than lead-acid batteries. Lead-acid batteries can overheat if charged too quickly, but with lithium batteries, you don’t have to worry about overheating, and you also don’t have to worry about waiting too long to charge.
Lithium Batteries Have a Higher Energy Density
Lithium batteries are considerably heavier than lead-acid batteries, but as long as you have the right help, you should still be able to install them with no problems.
The extra weight actually comes with an advantage, and that’s energy density. Energy density refers to how much energy a battery can hold in a given amount of space. Lithium batteries can fit more storage capacity into a smaller amount of space. For example, it would take eight lead-acid batteries to power a 5.13 kWh system, but you’d be able to power the same system with two lithium batteries.
So, while your lithium batteries are heavier, they are also smaller, meaning you can fit them in tight places if you have to.
Lithium Batteries Have a Higher Depth of Discharge
The depth of discharge of a battery refers to the overall capacity that gets used before the battery is recharged. You really shouldn’t discharge your battery 100% when you use it. Rather, you would use a certain amount, and batteries typically come with a recommended depth of discharge that will tell you how much to use before refilling.
Lead-acid batteries have a depth of discharge of 50%, meaning it’s recommended that you only use 50% of the battery before refilling. Otherwise, you could negatively affect its lifespan.
Lithium batteries, on the other hand, have what are called “deep” discharges, because they can go longer without needing to be refilled. With lithium batteries, you can use 80% of the battery before refilling it.