How Solar Batteries Differ from Car Batteries

If you look at a solar battery, you might think that it bears a marked resemblance to the battery in your car’s engine. Solar batteries might be slightly bigger, but they have the same connection terminals on the top and a very similar appearance on the outside. But don’t let looks fool you. Solar batteries and car batteries have many differences. Keep reading to learn more about these differences and why these battery types are far from interchangeable.

Different Battery Types

There is quite a bit of overlap in the battery types used for cars and those used for solar power storage. That overlap primarily contains lead-acid batteries; this chemical composition is the most popular type for car batteries, but lithium-ion has quickly become the more common choice in solar applications. Even though your car and your solar power system can both use lithium-ion batteries, this is essentially the only battery type that can be applied in both situations. Other standard solar batteries, such as lithium-ion and salt water, are not applicable chemistries for vehicles.

Surges versus Sustained Power

Your car battery isn’t designed to provide prolonged power usage. Instead, it simply provides a spark to ignite the engine and burn fuel. These are known as SLI batteries, short for “start, light, and ignite” because their purpose doesn’t extend beyond that ignition. On the other hand, solar batteries are meant to discharge over prolonged periods, providing your home with sustainable electricity. 

Just think about how quickly your car battery dies when you leave it on without the engine running. With such a limited power supply, it would be practically impossible to run your home off of solar power stored in these batteries without filling a room with them.

Depth of Discharge

One of the reasons solar batteries can provide a more prolonged source of power is that they have a greater depth of discharge (DoD). This allows the batteries to empty more of the energy stored in them without damaging the battery or shortening their lifespan. On the other hand, car batteries are meant to provide a very shallow discharge for that moment of ignition; discharging them beyond that (like when you run your battery until it dies) can damage them.

Hopefully, you weren’t ever planning to connect car batteries to your solar power system. But if you were ever curious, now you understand a little bit more about why a car battery is not a viable replacement for a solar battery when it comes to powering your home.

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