From the posts here from members that reside in your region of the world, batteries for the R65, are quite pricey .
There seems to be battery replacements for garden tractors, that will work in the R65 .
If you can get an AGM type battery without breaking the bank, they seem to be better than the typical 'flooded', or serviceable type .
I have the same battery as Monte, swapped it over from the R65 to the oilhead in January, only about a year old, so I don't know how long it will last in this hot weather testing area that I reside in .