Replacement Battery

[woodnglass]

I have a Roketa MC54-250 and it's the Honda clone. I don't think my OEM, and it's hardly been used, is drawing the necessary voltage. The scoot has been idle for a few weeks as well as weather getting colder and the battery was dead when I tried to start it today. I put the battery on a charger and voltage readout on the charger as well as a multimeter show somewhere around 11.5 volts. There's also an error message on the charger which indicates a bad cell. Even though the OEM has hardly any time on it I'm inclined to just get a new reliable battery. If I replace the battery with, say, a Yuasa should it be a 12V9AH as is the OEM or can it be 11 or 12 AH. The Haynes manual shows the Reflex as 11AH. I'm pretty new to some of this electical/mechanical stuff and am wondering if the extra AH is not necessary, preferrable, or not a good idea.
I suppose what I'd really like is to hear what batteries are recommended from folks with essentially the same bikes that have replaced the OEMs.
Thanks a bunch,
Jer

[Gary]

Other than cost, there shouldn't be any downside to a more powerful battery (if it fits), but it proabably isn't necessary. I'm using a Yuasa 9ah and the scoot starts first time, every time.

[hillbilly]

I think a stock sized Yuasa would be the way to go. An extra a/h or two doesn't hurt anything but the problem sounds like it is really just a bad battery so you might as well keep it simple.

[woodnglass]

Gary,
Could you tell me if you bought your Yuasa locally or online and if so where?
Thanks,
Jer

[Gary]

I bought off the internet: store.bobscycle.com/browse.cfm/4,64370.htm?AFF=690FGL

Yuo might be able to find a better price elswhere.
Gary

[scooterollie]

My philosophy about batteries has always to go larger and better quality, if at all possible. I replaced two O.E. lead acid scoot batteries with one size larger "AGM" style batteries. Not only better quality but lower discharge rate on standing, more cold cranking amps and more amp hours. Going to a larger capacity battery - 9 Ah to 12 Ah, for example - is not a problem as far as the charging system of the engine goes. The "Ah" rating only refers to reserve capacity and will not put an undue strain on the charging system.