The first thing you have to do is to calculate what you ‘needs’ are. That means everything you will be powering from your inverter. Everthing! Coffee makers, lights, TVs, PCs, fridges, freezers and etc. and etc. Some things like coffee makers and toasters draw high currents for short periods and others like lights and TVs low currents for long periods. It will also vary my season and weather. Once you have worked that out you know what you require in KWH from the battery system. Add at least 20%.
Batteries are usually rated by VDC and AH capacity. That means you need a battery that matches the output of your charging system and the input of your inverter. Generally the higher the voltage the more efficient the system.
At this point you go looking for a battery. It absolutely has to match the charging system and inverter input voltages.
Used nickle/metal hydride batteries from electric cars may be possible. Lithium type batteries may be possible. I doubt very much if they would be cost effective due to their voltages, charging profiles and cost.
What’s left? I’ll be damned. Flooded lead acid (FLA) batteries! What? The FLA battery has been around for over 150 years! Isn’t a new technolgy better?.
But no newer technology can give you a more cost effective solution.
FLA batteries are a commodity product. They are manufactured and used by the millions. You can buy new and used FLA batteries that will last for years with decent installation and maintenance. They are green too. Over 95% of the lead in an industrial battery is recycled. So is the acid and plastic.
If you are going to use FLA batteries you want ‘A’ battery of the desired voltage not a bunch of batteries in parallel. Big 2 volt cells in a string like the telephone companies use or a forklift battery of the right voltage. That way if a cell goes bad you can have it replaced.
If you do your homework per paragraph one you have choices. Stick with flat plate batteries. Tubulars have more power but also cost more and have a different charge profiles.