I have 4x 12v 7.2 batteries
sensible maximum current is going to be about 5 amps but any decent charger is going to self-limit.
5 Amp charging into a 7.2 Amp Hour battery would be OK only if the battery was capable of being fast charged, if they are not designed for fast charging then 5 amps will damage them.
As mentioned before.... check the battery's data sheet about charging rates