Just wanted to put in a good word for Motobatt. My scoot recommends a 4ah battery, but for size I ended up with a MBTZ7S 7ah that lasted me 5yrs with avg 3x/wk daily use. Got it from PartsforScooters for $80 plus shipping. Technically I got 4yrs, cause every few months I had to recharge it during the 5th year. (use a Battery Tender Junior).
Just a month ago I replaced it with another Motobatt, MBTX4U for just over $50 including shipping. Its a 4ah, smaller than the MBTZ7s, but fits fine with a small block of wood. Its starting great, even on cold mornings. I'm sure you can find Motobatt cheaper but I've been very impressed, in fact, I was getting slight surging at full speed wtih my old Motobatt, but since getting the new battery the surging went away.
