The Voltage of a battery can never be as high as the generator voltage.
24V Batteries have an idle voltage of somewhere between 25 and 27V.give or take a %.
the generator will give 28V
Once you have started your engine a lot of the battery's power will be depleted.
Imagine you are out in the middle of no and the only option you have are two truck batteries. no charger. you need multiple starts on those batteries. now what?
never had any problems