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Battery Disconnect/Kill switch

Old 11-26-2018, 09:33 PM
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Default Battery Disconnect/Kill switch

Information overload!

What is the correct way to wire a 4 pole battery disconnect/kill switch in a Miata?

What about 2? One internal and one external.

Yes I searched around on the forum......................................

Thanks in advance
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Old 11-27-2018, 11:17 AM
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Old 11-27-2018, 01:33 PM
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Thanks Wink!


So the "Battery Positive" is the charge wire off the alternator? I keep coming back to the "Grey wire with the Red trace" That sound correct?

Last edited by Bri1062; 11-27-2018 at 01:34 PM. Reason: spelling
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Old 11-27-2018, 02:11 PM
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I would strongly advise that you determine whether or not your specific switch is designed to have the alternator current flowing through it. There are 4-pole switches which are, and some which are NOT.
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Old 11-27-2018, 05:39 PM
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Originally Posted by Savington View Post
I would strongly advise that you determine whether or not your specific switch is designed to have the alternator current flowing through it. There are 4-pole switches which are, and some which are NOT.
^^ This. Many 4-post kill switches are only meant to interrupt field current on the second pole, not alternator output. Running one of those on the alternator output will make your car run like ****. And then when you shut it off with the engine running, it can cause further damage since it lacks a resistor to provide run-down load.
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Old 11-27-2018, 06:18 PM
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Who is making a quality switch with the internal resistor?
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Old 11-27-2018, 06:26 PM
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We have used these for years with success.

Longacre Battery Disconnect Switch 45782
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Old 11-27-2018, 07:34 PM
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Now that's the kind of information I am looking for! Thanks Emilio!
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Old 12-18-2018, 04:48 PM
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Emilio when you wire yours up do you use the same size wire for all of it? What is your recommendation?


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Old 12-18-2018, 11:04 PM
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We keep the wire gauge the same as OEM everywhere. We use a high quality welding cable instead of the OEM cable. Same with the alternator wiring. I think the only thing we do differently than the Longacre diagram is a jumper between A and B (where the 175 amp circuit arrow is) and then run a wire from B back to the battery. The other B goes to the starter and the fuse block.
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Old 12-18-2018, 11:52 PM
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Cool thanks for the reply. I have a spool of 4awg I was going to use but that might be a tad heavy
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Old 12-30-2018, 06:38 PM
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Originally Posted by matrussell122 View Post
Cool thanks for the reply. I have a spool of 4awg I was going to use but that might be a tad heavy

https://goo.gl/images/q1TAMs

good guideline
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