I decided to build this maintainer/charger after looking through the vast amounts of battery maintainers that were high priced and didn't do what I wanted it to do. The first quality I wanted in this charger was for it to be relatively small in size so it could be put in areas with limited room. My second quality that was also related to the first was for it to be mounted on tractors, vehicles, or anything that could use a charger like this to help extend the life of the battery. Another quality was for something that is easy to use and anyone with even the minimal mechanical knowledge could do quite simply and quickly. The last quality I wanted from the device was to be completely hands free and automatic; as the battery brings the voltage up to its desired target, it automatically turns off to save power. If the battery were to go lower than the voltage threshold the charger will automatically start again. This makes the charger extremely simple to use with no worry of overcharging the battery.

Here is a picture of the prototype circuit board to run the charger. I'm sure it will be updated quite a bit but it does the basic function of charging and maintaining a battery (12 volt only).

Very fancy.

It’s coming along pretty well. Need a bigger power supply though.

It's a good start.

Circuit boards are in!!! Although looks like I will have to remake them as there’s hardly enough room for the components and the holes for the leds, battery output, and other stuff I accidentally made too small. Oh well. These will still work as prototypes.