Hi Randy
I use a sealed 6v battery for my 60 and 50 Sport models.
It's called 'Drypower' made in Vietnam. Code 6SB2.8P, 6V 2.8Ah
Dimensions 65mm wide x 32mm deep x 97mm high. I have used Chinese copies of a Yuasa in the past they are wet acid batteries of 2.0 Ah and don't last as long.
I hope this helps
RayK
Australia