Usually when a charger LED is on this stage of charge, the batteries are almost fully charged when the LEDs change to green or go out, then the batteries are fully topped off. It is best to wait for them to be fully charged before use to avoid any "memory" effect where they remember being partially charged and will not take a full charge past this point in the future.

A battery charger just charges the battery, a maintainer helps keep the charge in the battery while its not being used or is in storage, they do work good, because I own several of them, and use them on the vehicles. I don't drive much, but when I go to start them they always will fire right up. But you have to have a good battery to start with other wise it won't actually charge a battery up, all it will do is help maintain what voltage the battery already has in it, good luck.

Both terms are essentially meaningless. There is no standard in the industry, so manufacturers can use the terms in different ways. One of the problems with terms like these is that the amount of time it takes to charge a battery is dependent on the capacity of the battery being charged. A charger that can charge a standard capacity AAA NiCD battery (180 mAh) in just one hour might take 8 hours to charge a high capacity NiMH (1500 mAh) battery. It's best to ignore such terms and make a rough calculation of how fast a charger can charge batteries.