If you are looking for batteries for a solar system, you have to choose between two types: deep cycle and shallow cycle. Deep cycle batteries are designed to be discharged up to 50% of their capacity over a long period of time—so they’re good for solar systems or wind turbines, where the energy is stored in the battery and used later. Shallow cycle batteries are designed to be discharged only 10–20% of their capacity over a short period of time—so they’re used in cars and boats, where the energy is immediately available.
You should definitely get deep cycle batteries! They have more usable power (1.8kWh) than shallow cycle batteries (75AH-150AH), which means that they can store more energy for you to use later. In addition, deep cycle batteries can be charged back up to 500–600 times before they need to be replaced—which means that you’ll get more life out of them than shallow cycle ones (200+ cycles).