I have a Black and Decker Charger. The price was 105$ It charges at 4 amps, 10 amps, 20 amps, and 40 amps. It also has an equalizing setting that evens out the charge in all the cells. There is a desulfating setting that revitalizes the battery. ( It increases the life of the batteries) The charger has settings for agm,wet cell batteries, and gel batteries. It also has a 110 amp starting setting. They can also be purchased from Amazon.
It is a "smart charger" Mine is 6 or 7 years old.