Show me your battery (not ignition) cut off switch location.

[jerryasi]

Much I don't know about automotive electrical, I just grounded my negative lead, through my kill switch to the body. Routed the positive lead with the fuel line, if there's damage so significant as to damage both fuel and power, I want a fire. 

[jerryasi]

Much I don't know about automotive electrical, I just grounded my negative lead, through my kill switch to the body. Routed the positive lead with the fuel line, if there's damage so significant as to damage both fuel and power, I want a fire. 

[jerryasi]

I think on this forum, I was advised to put the kill switch on the negative side of the battery. Someone else brought to my attention the BMW plastic clips I used to mount the battery positive and fuel line (cunifer) to the underside of the car.

[quequieresvonmir]

This is how I did it

[Dudeland]

19 hours ago, '76mintgrün'02 said:

 

Mine was made by HEYCO. 

 

10mm for the positive and 13 for the negative.

 

 

It's got a magnet behind it.

I think you are mistaken  .  That is an ignition key for a D-series caterpillar bulldozer.  

[Dudeland]

15 hours ago, jerryasi said:

I think on this forum, I was advised to put the kill switch on the negative side of the battery. Someone else brought to my attention the BMW plastic clips I used to mount the battery positive and fuel line (cunifer) to the underside of the car.

I think it depends if the car is a negative ground vs. a positive ground.   I do know that I will be switching the alternator charge wire, as the point of having a shutoff (to me) is to kill the engine, even if it is running.  If you just break the battery wire, it will still run as the alternator will supply power to the system.  I think it was @TobyB that gave me that tip a while ago. 

 

I do have this recurring fantasy that I could do some hill climbing competitions in this car. The reality is that it won't be built to any spec, and I really don't have the energy to do so, as this will be 95% street-driven.  This is more of a safety thing, it really won't stop someone from taking it either, as the key for these shutoffs is not unique and even a cursory Google will tell you how to jerry-rigg one. 

 

There aren't enough mashed potatoes in these cars to hide the pea-sized anti-theft countermeasures under, so I won't try.  

 

I will be running the wires inside down the passenger side of the transmission tunnel. I want to keep them away from rocks or other nasties that may produce sparks next to my fuel lines. Keeping the power wires internal and towards the center of the car means that if I get t-boned they won't short out against the shards of my rocker.  Also, they won't bulge out the carpeting as I will bring some floor insulation up flush to them. 

 

Regards

 

 

 

[jimk]

15 hours ago, jerryasi said:

I think on this forum, I was advised to put the kill switch on the negative side of the battery.

 

18 minutes ago, Dudeland said:

I think it depends if the car is a negative ground vs. a positive ground. 

On a negative ground system, if the ground is open by a switch and something shorts the positive battery side to ground, nothing happens.

If the switch is on the positive side and something shorts the system between the switch and the battery positive post to ground, sparks fly.

[Dudeland]

6 minutes ago, jimk said:

 

On a negative ground system, if the ground is open by a switch and something shorts the positive battery side to ground, nothing happens.

If the switch is on the positive side and something shorts the system between the switch and the battery positive post to ground, sparks fly.

I can't switch the ground to the alternator, so how do I kill the engine by turning off the switch?

[slowbert]

To kill the engine, you will need to kill the ignition, not the battery.  In my set up, the car will continue running when the battery is switched out (if the alternator is generating current).

[jp5Touring]

Mine is a positive cut off switch done by PO.

 

[Rosso Pintura]

PSA: a cutoff switch goes between the positive pole of the battery and the starter. The other side of the switch also connects to the main “hot” of the fuse box. The switch is intended to be accessible to corner workers or emergency personnel to shut your car down in case you become incapacitated in an accident, not buried in the trunk or elsewhere hidden. To prevent back feeding from the alternator proving power to the ignition, you either need a switch that provides a break to the ignition which are the ones with spades on the rear between the two poles, or a diode installed in line, coming from the exciter wire of the alternator acting as a one way only path for power. For the rest of the world who want one just for the sake of removing the battery power from the system for reasons of your own, I guess you can put it wherever you want. 

[Dudeland]

38 minutes ago, Furry Camel said:

PSA: a cutoff switch goes between the positive pole of the battery and the starter. The other side of the switch also connects to the main “hot” of the fuse box. The switch is intended to be accessible to corner workers or emergency personnel to shut your car down in case you become incapacitated in an accident, not buried in the trunk or elsewhere hidden. To prevent back feeding from the alternator proving power to the ignition, you either need a switch that provides a break to the ignition which are the ones with spades on the rear between the two poles, or a diode installed in line, coming from the exciter wire of the alternator acting as a one way only path for power. For the rest of the world who want one just for the sake of removing the battery power from the system for reasons of your own, I guess you can put it wherever you want. 

I think we are getting close. 

 

This is what I am thinking.  

 

Battery and Alternator (and exciter wire) to Terminal 1 on the switch.  This would eliminate any backfeeding through the exciter wire to the rest of the system through terminal two correct?

 

Terminal 2 goes to Starter and lead(s) for primary and secondary fuse boxes (stock body box and the secondary one for EFI et.al) 

 

I could (and may) put a second external switch in line with terminal two so that if either one is tripped, everything is dead. 

 

With that being said, there is a threat for the live positive wire going from the battery to terminal 2 to get shorted out in an accident   An appropriately sized fuze at the battery should cover that situation. 

 

In the case of an accident, I do have an inertial switch that cuts off the power to the fuel pump, just in case I am not conscious. 

 

 

 

 

 

[2002#3]

'74 tii - same as '76mintgrün'02 (a 10/13-mm wrench magnetically attached to the body and close to the battery)

 

'70 - See photo below.

 

[SydneyTii]

6 hours ago, jp5Touring said:

Mine is a positive cut off switch done by PO.

 

Still these are a good way to secure the battery if you put it in the trunk, very solid and gives you somewhere to tie your toolbox to, multi use battery holder, isolator switch and tie off point…. Note I didn’t say brace😜 

[Dudeland]

4 hours ago, SydneyTii said:

Still these are a good way to secure the battery if you put it in the trunk, very solid and gives you somewhere to tie your toolbox to, multi use battery holder, isolator switch and tie off point…. Note I didn’t say brace😜 

I have a subwoofer (for the chicks 😂 ) so I got a bespoke optima battery tray that I will  mount in the front left corner of the trunk, leaving space for the “Booming system” . 

 

I did consider a brace but trunk space is at a premium for different reasons. 😎