AO

So I was at Harbor Freight the other day and they had this thing for like $3, so I decided I'd pick it up and see if I could figure out a way to make this work because unscrewing that damn bolt is a PITA and while I've converted mine to a wing-nut (I guess technically it's a wing-bolt), I think it would be much more elegant to just pop the "key" out this thing and have the power cut off.

So, has anyone BTDT? - Oh yeah, I'd like it to be and internal installation, not something that sticks outside like on a race car.

hacker-pschorr

I've helped install a few of those on race cars - where the key is actually exposed to the outside.
Never on a street car.

I have a low profile battery cut off that goes on the terminal - spin the little wheel = battery disconnected.

It wouldn't be too hard to mount that on the tool panel - run the negative line through it.

ceedee

it looks pretty much like this one
battery kill switch

DonT

This was installed on my shark when I bought it. They spliced it into the NEGATIVE battery cable. It's tucked behind the tool cover.

j.kenzie@sbcglobal.net

Andrew,
You might be able to mount it behind the tool panel so it's easy to operate but not visible. You might just mount it on a brass tab to the old wing nut hole then run the ground cable through it. Depends on how much room you have and how accessible you want it.

AO

Thanks Don for those pictures. I guess I was thinking I should hard-mount it to something, but maybe it's okay to have it loose... hmmmmm.

Hawkeyes

Andrew,
Yeah it's the s--t!. No more dead battery or fried wires. I did mine, got it from another Rennlist post:
http://members.rennlist.com/pirtle/z0_keep_main.html
scroll down to Electrical or just read on...

'I finally got around to mounting an auxilliary battery switch in my 90 GT and it ended up being fairly easy.

I bought a battery cut-off switch from Racer Wholesale, a simple one with a red removable switch handle.

I will be needing a master switch accessable from outside the car for the track, so this will be it, when I finish routing a removable wire lanyard from the switch to the drivers side of the rear hatch, and slap on the "lightning bolt" decal, required to tell corner workers where the switch is.

• I made a right angle bracket from 1/8" aluminum stock, and bolted that down where the famous battery strap "wing-bolt" goes.

• I then bolted the switch, by one terminal, to the right angle bracket.

• Then you attach the battery ground strap to the other terminal of the switch.

• I then cut a slot in the "tool tray" that covers the back of the hatch area so that it will slide down onto/over the switch without removing the red "Key".

• So now just to the drivers side of the hatch latch, under the 'bulge" in the tool tray, that switch faces forward and is protected from most stuff in the trunk by that little bulge in the tool tray.

Now, when I have to work on the electrics I just flip the switch off instead of having to undo the ground strap.

For the track, I clip a lanyard onto the switch. The lanyard is routed through metal 1/4" tubing in the spare tire well and out through the weather strip on the hatch, and is removed when not on the track.

Can't believe I never did this long ago. $12 bucks and a couple of hours.

Don Hanson

To do it this way means cutting the tool tray 'slot' for the red key, but it looks custom & the key is easy to get at. It's also protected from stuff rolling around in the hatch. I like it.

Hawkeyes

SteveG

This is what I have. Conveniently located is a big plus, but I worry I might nick it getting in and out, if I were to break it off, could be a problem. I bought two from HF just to have a spare key.

DonT

The only drawbacks that I've seen - you lose the presets on the radio & you always have to reset the time on the clock.

ew928

AO,
I upgraded from the bolt on the ground cable to a plastic knobbed bolt instead of the wing nut.
I've always associated kill switches with race cars and not road cars.
But then I've got the solar panel constantly connected to the car's electrics.

Don T, how long does it take for the LH to relearn the variables on your SC car?

docmirror

Well, you all should realized that each time you disconnect the battery, not only is your radio probably lost, but all the engine characterization in your LH and EZK is also gone. The LH uses a enrichened circuit for the engine management for the first about 40-60 minutes from the time the battery is reconnected.

There are keep-alive circuits in the LH that will store your values of O2 voltage, MAF wire temp, engine temp, and a few other sensor outputs. These values are lost when you disconnect the battery for more than a few seconds. If you use this disconnect regularly on the 85 and up cars, your fuel economy will be horrible, and you'll be building up significant carbon deposits in the combustion chamber.

The solution is to get the resting current back down to factory values, and use a trickle charger when the car isn't moved for more than a week. Although I like the batt disconnect idea, for the later model 928, it isn't really suitable unless you don't drive your car for long periods. I use these switches for security in motorhomes and boats that are in storage for long times.

Mike Frye

I was thinking of putting one of those in also, I'm putting a compartment for a fire extinguisher where my rear seats used to be, I think the switch will go in there as well so all the safety features are in one place.

Ernest has a good point, for the 87+ cars, the LH has to relearn as well as the radio presets, I would only use it as a safety device or easy way to disco power when working on it, not every time I'm out of the car.

EDIT: Doc beat me to it.

BTW- In the past few weeks some people have posted that the '85-'86 have to 'learn' after powering them down, and others have said there's no learn function until '87. Does anyone know for sure on the '85-'86 (something near and dear to my heart)

Alan

Andrew you mean like this...

It was posted well over a year ago

You need to get really good low extra resistance = big construction, close to battery & no extra run - ground strap is obvious and much easier to reach than +ve...

Note to all - you cannot use this kind of battery switch as an engine cutoff switch - the only really safe way to shut down the engine is to turn off just the ECU's/Fuel Pumps.

If you disconnect the battery the car will still run but voltage regulation will go to hell... and may well take other stuff with it...

Alan

AO

I guess I should have been more clear. I am not experiencing any problems with my battery, nor am I looking to use this to kill the engine. I just thought this was a more elegant way to disconnect the battery.

Alan... that's a nice setup.

Alan

BTW - you can buy spare keys for these individually and you can also cut the key off flush & just saw a screwdrive slot in the end for operation (see the final pic for this.. = no hole in tool panel.

AGAIN THIS IS NOT RACING TYPE CUTOFF SWITCH !!! IT WONT WORK GUYS!!

Alan