Yeah I end up fixing just about every single one of them to be in working order, hence former glory.
And actually now most of them have working batteries, just some have quite short running times.
I have the easiest times getting the Dell latitude batteries because the entire C series share one battery, and D series batteries are quite easy to find locally and I just get some in good working order for like maybe 15 bucks each.
ThinkPad batteries are also decently easy to find, not as easy, but I managed to get most of them working batteries.
Then the HP Compaq business laptop batteries are the hardest to find, but luckily none of my HP's except for my Presario CQ56 actually have a defective battery, while the CQ56 is used primarily for Zoom in my bedroom so I don't care.