i believe 12v batteries when they can no longer be used in a car, you could use for home for another 3 years

below are what I think are inverters you can use for that application:

https://www.sunstore.co.uk/product-category/solar-accessories/power-inverters/page/2/?srsltid=AfmBOopbh3I0PoJzxZVgkyxhMCcmhkHZSNv4NzdOWkLuU2E8JVFuDkjB

victron inverters are well suited for this task.

Other Notes

https://diysolarforum.com/threads/interfacing-lead-acid-batteries-with-inverter.61778