I should also point out that it's easy to keep a battery mounted. All you need is to buy or 3d print
one of these and then bolt down some velcro straps on the sides of your battery. You can also have a tight fitting enclosure to put it in and you don't even need the plastic bit. (Not too tight though, our 2015 bot is responsible for some nasty scrapes on a few of our old batteries
)