I'm starting the process of designing my electrical system and have a question about the placement of the starter relay. Does it have to be close to the starter or can it be close to the battery? My thinking is if I have a 10' long cable going from the battery to the starter, why would it matter where I break it for the relay?? Thanks in advance for your input.
Van's Air Force
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Starter Relay
- Thread starter Morepower
- Start date
Conventional GA starter relay placement merely ensures the section of starter power feed cable running forward along the engine (the hot vibrating thing) is dead when in flight. The start contactor can be anywhere which satisfies that criteria. It's usually on the firewall, even with a rear battery, because it provides a convenient point to connect a main bus feed.
Amplifying on Dan’s post - if you have a rear-mounted battery, with a rear-mounted Master contactor, you can also put the starter relay way back there - theat makes sure the big fat starter cable isn’t energized in flight, and if a short does develop due to wear or vibration on teh cable, you’ll find out about it on the ground when you hit the starter button. So no - you don’t have to have the relay close to the starter.
