[Callasports]

Here's a question that's been on my mind for a while. In fact, I've searched through some threads on Miata sites but didn't see what I had hoped to find.

I have a battery disconnect switch with the little red handle that I want to install in the trunk. The main purpose of this is to protect my car and my house when I leave the car sitting still for a week or 3 at a time... And, it could also be helpful and slow down some fool who wants to do naughty things with my Miata.

The question is: Would you wire the switch on the positive or negative side of the battery? I have a '94 NA, and we all know the positive battery post is easier to get to, but I have a concern with brass/copper lugs on the bottom of the switch being wired "hot". Should I be concerned about that? (I'm sure I could fabricate some protection for the "hot" wires & connections.) Should I wire it to the negative side of the battery and not have any more sleepless nights worrying about this?

It just seems that shutting off the positive side of the battery would offer the car more protection from something grounding out (shorting out) when it's least expected? I'm not an electrical engineer, but I did stay at a Holiday Inn Xpress...

Thanks for your input. Out of town tomorrow. I'll check back Wed, the 28th.

 

[Callasports]

Anyone have an idea to share? It's not something I'm installing tonite, but I look forward to hearing what you suggest.

This also serves as my own bump...

 

[LUV2TURN]

Pretty good question. If you had the option, it'd be great to have a switch that interrupts flow both on positive and negative sides. Either side you put it on, however, is going to be equally effective.

Doesn't really help you make a decision, does it...

 

[frictionfighter]

i have a cut off switch, its hooked to the negative terminal. if you put it on the positive you may get some serious spark action and light up your miata.
so definatly do the neg.

 

[freedomgli]

http://www.marphis.com/batterycutoff1.htm
http://www.ffcobra.com/FAQ/battery.html

 

[Callasports]

THANKS for the follow up. I'll read though the attached links, but I'm leaning towards cutting off the negative I guess. I guess I just worry about the "potential" energy with the hot side left on all the time.

No problems or concerns for you, Frictionfighter?

 

[asianrice02]

i'm not sure if anyone else experiences this but my alarm goes off everytime i disconnect the battery. i would guess that the kill switch my do the same thing

 

[roadsternut]

Its routine to disconnect the earth before the positive, so the answer is rather obvious.

 

[ryster]

i was thinking about putting a kill switch too... but i was thinking of a fuel pump cut off switch so you would'nt need to reprogram you radio every time you turn it off. but the thing is i am not sure where to cut wires... any i deas?

 

[roadsternut]

Don't you guys in the US get engine immobiliser systems. Much more professional, and they don't cost a lot.

 

[dc2696]

I want to do a pump cut-off aswell. I haven't looked to much into it so I'm not sure of the best place to interrupt the signal, any suggestions?

 

[ghostofwar]

Bump for an answer to the fuel pump kill switch.

 

[H_C]

Has anyone put a battery kill switch inside their Miata (not in the trunk).

It'll be extremely useful since my Optima is so tall, a standard screw-on one won't work well.

 

[violation]

good questions all around! i have no helpful input at all, but i'd like to see the answers.

 

[webba1]

Fuel pump kill switch would be my vote you can run a thinner gage wire to wherever you want in the cabin/engine bay/trunk and have it hiden. All you would have to do is spend $5 on a switch and some wire and the possibilities of hiding spots become endless. It shouldn't really matter where you splice into the one of two wires leading around the driver side door as long as you interupt current flow.

If you were to disconnect the trunk release lever (I think there is a writup for it on .net/super simple) you could have a much safer system (can't enter trunk w/o keys--can't flip switch w/o entry into trunk) but you would still have to deal with putting a switch in line with some heavy gage wire.

 

[H_C]

Well, for me, security is not an issue.
It's just in case I don't drive for a couple of weeks.

Don't want to waste my valuable battery's massive power! 8)