Starter and deep cycle charging differences?

I too tried after seeing the OP question, but they are not very clear.

In fact We have quite a few of battery operated trolleys. What I have seen is that when it is deep discharged, (the voltage dropped down and the trolley dead- once it happened) the deep discharge mode was to be activated and it took a whopping 50A on 48V+ (don't remember the voltage but it was a bit more than that but the amperes stuck to mind because of the abnormally high value) to charge them back and that too for somewhere like 12 Hrs. In fact after about 8 Hrs of this heavy charge the ampere dropped gradually.

The charger is programmed with the switches on deep discharge and normal modes as the OP mentioned.

Normally these are charged at normal mode and much lesser ampere (the batteries are of course deep cycle batteries)

Seems like the deep discharge mode forces heavy current whereas the usual (normal) is trickle charging mode. But that is only my conjecture and not sure (so didn't want to show my ignorance ).