Starter/batt disconnect switch

[ontherocks83]

So this may be a dumb question but as that my boat is 30 years old I am not familiar with new set ups.

On some newer vessels I have noticed that along with your battery selector switch there is also a starter motor battery disconnect switch. Essentially will either supply power to or completely disconnect your starter from the battery. I'm curious as to the reason for such a switch. Having always had my starter connected to power I can't see the reason for wanting to disconnect it regularly. Like I said may be a dumb question but I am just curious.

Thanks

[goboatingnow]

to allow yo to disconnect the batteries completely , for example if you want to work on the engine or remove a wire etc. Its good practice to have disconnects on ALL batteries and I believe most boats have just that

dave

[ontherocks83]

Oh I see that whole safety when doing maintenance thing , that makes sense. Thank you for the reply! I honestly missed that all together.

[skipmac]

Originally Posted by ontherocks83

On some newer vessels I have noticed that along with your battery selector switch there is also a starter motor battery disconnect switch. Essentially will either supply power to or completely disconnect your starter from the battery.

Depends on how the batteries and the switches are wired. A system could be wired to allow house batteries to be switched to the starter in case the starter battery dies and/or wired so the starter battery could be switched to supply house power in case those batteries died or wired so neither connects to the other in any switching combination.

Originally Posted by ontherocks83

Having always had my starter connected to power I can't see the reason for wanting to disconnect it regularly. Like I said may be a dumb question but I am just curious.

Thanks

Like Dave said. It's a good idea to be able to disconnect power to the starter when you're working on the engine or wiring. Also, it's rare but occasionally a starter solenoid can stick so the starter keeps on spinning, even when the key is turned off. In that situation disconnecting power to the starter could save it from damage.

[FlyingCloud1937]

Originally Posted by skipmac

Like Dave said. It's a good idea to be able to disconnect power to the starter when you're working on the engine or wiring. Also, it's rare but occasionally a starter solenoid can stick so the starter keeps on spinning, even when the key is turned off. In that situation disconnecting power to the starter could save it from damage.

I have repaired 2 boats this year that had that exact same problem. Also one anchor windlass.

It seems that the quality of solenoids aren't what they were.

Lloyd

[smac999]

also if there is a fire on the boat you want to be able to disconnect the battery power. this is why battery switches should not be in the engine room (where the flames and smoke will be) but somewhere accessible.

switches on all batteries is abyc code. as is the location.


it also helps prevent any unwanted drain on the engine batteries if left sitting long term or at anchor.

also makes the boat safer to have less live wires on the boat at any time. no need to have the swtiches on unless you are using the engines. especially when those ones are normally not fused.