Countless companies and industries enjoy making up scary stories when it comes to justifying their opposition to making it easier to repair your own tech. Apple claims that empowering consumers and bolstering independent repair shops will turn states into “hacker meccas.” The car industry insists that making it easier and cheaper to repair modern cars will be a boon to sexual predators.
On my RadCity 5 Plus, it was a 10 amp red mini-blade fuse. I had a “variety pack” in my car that I’d gotten at a local auto part store, but looked it up any way, just in case. This may be different on other models/batteries. Ironically, it did require a warranty voiding opening on the battery casing. :-)
Fwiw those “warranty void if opened” stickers are not legal
Fwiw, any statement like this is worth less than what you’d have to pay a lawyer…