[Gangplank]

This ^^. You have to register the battery.

Get a battery tender & plug it in every now & then to keep it charged. There are all types & brands. I have a pretty inexpensive one by Black & Decker. It takes a while to charge but overnight does a decent job.

I had a Deltran Battery Tender Plus for years & it was great. Not the least expensive out there but it worked great. If the B&D stops working I'd get another Deltran.