is the 4A rating the standard rating or quick charge?
As to the charger, there are two types; constant current and constant voltage.
Constant current chargers (optimate type) control the rate of charge (not the battery!) by the charger adapting the charge rate it avoids overcharging the battery.
Constant voltage just keep going and typically put out higher output than is recommended for normal bike batteries. (eg 4A!)
Yuasa quote two different batteries for my Tiger, one is 1.4A and the other 1.1A. This is typical of bike batteries.
YUASA
Linear Mode
