Batteries can be finicky. Last spring, one of mine was dead slow on the crank and so I got a new battery.
That battery is still sitting on the shelf with that separate acid bottle and the bike is back to behaving itself.
Had two V9's in a row where the battery didn't last six months.
One Harley battery that went seven years in the bike and then four more years in the riding lawnmower. The replacement YUASA died six weeks later.