[Spridgets] Batteries, no LBC content

[derf]

I would probably go with a sealed battery in a jet ski.  They take a
lot more abuse than a lawnmower.
You don't want battery acid spilling inside, do you?
That being said there are some dual sport motorcycle batteries that
would probably work and be cheaper.  The Suzuki DRZ400 comes to mind
as being small and sealed.
They do tend to charge more for "marine" stuff than everything else.