Difference between maintenance charger and charger

In the past, the term maintenance charger referred to a small current single-stage charger that would be left on a battery to replace the small self-discharge of a battery. Over time with switch modes charging the term maintenance remained but now is more about the total amount of current available.

A small current charger can only be used to maintain a medium-sized battery but if used on a small battery a multi-stage charger is more than sufficient to charge a small battery.

So, in summary, most multi-stage chargers have a charge profile and maintenance profile. Its the current available to charge than needs to be matched to the correct sized battery to become a charge/maintainer. Otherwise if to low current on too large a battery they are really only maintenance chargers.