A Lead-Acid Battery Charger

Lead-acid batteries started to come on the surplus market and seem to be everywhere at hamfests (Amateur Radio Hamfest). I picked up a couple to play with. They must have been out of some emergency lighting equipment. I was just starting to build some QRP radios (low power radios) and equipment and was looking for a power source so that I could operate remotely. That is when I decided that I really need a charger for these type of batteries. He is a picture of a sealed lead-acid battery:

This is a picture of a battery

Lead-acid batteries presents something of a problem to charge them. A sealed lead-acid battery had the following charging requirements: