40A Power Selector

Part of the reason I like Amateur Radio is emergency communications. In an emergency there is a good chance grid power will fail. When power is out I have 100AH batteries charged by solar panels. To quickly change to backup power, I have built a power selector that is operated by a switch next to my radio.

This selector has 2 relays to completely isolate the batteries from main power. The relays are standard 40A automotive relays. These are connected to a rocker switch that I had on hand. The distribution block has a fuse for the main and each output. The distribution block makes it easy to connect and disconnect equipment. It also helps keep wiring clean.