Help design a driver accessible master power cutoff!

At this point i am sorting out the best way to build a driver accessable power cutoff. Would like ideas that incorperate easy acsess by driver, main focus on panic situations.

Use a cable and handle, like a parachute or a fuel injection cut off lever.

Brian

Use two switches. One out back and one next to shifter

https://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/2892544/Searchpage/2/Main/237596/Words/%2Bcutoff/Search/true/re-inside-car-battery-shut-off.html#Post2892544

This is the simplest way. My buddy does it and puts the lever on a bracket just to the right of the seat on the floor. The lever stands straight up within easy reach.

My battery and master cutoff are both up front. Battery in front of radiater, switch on passenger side frame rail to right of radiater. I use a long morse cable to back of car. I will figure out how to bolt to the morse cable at the switch, then run the new cableback to the shifter area or up overhead by the parachute lever. Going up the side of the roll cage and mounting it by the roof/ parachute release seems to be about my best option?

I searched the web a few yrs ago and wanted this big button like a factor control panel would have or a main switch like on the back of a car but next to the driver within reach with a short lever on it.Here is the button that will do 40 amps and maybe just have ign,fuel on it

You already have all the hardware mounted in the car. No need to redo it if it works. Just piggyback a Morse cable into it.

I'm doing this on just about everything I get involved in. Just makes sense to be able to run it from the drivers seat for so many reasons.

I use a morse cable. You have the right switch lever already. Just use a longer bolt and attach morse cable.

Excuse the unfinished stuff we are getting there with the Dakota...

It does make sense for sure, McCalister
Al, looks great.
Clanton, that button was my first thought. No better deal than something you can slap quickly. I was thinking use a Ford starter relay, so not much juice required going through the button.

I would look at using a 250 amp R.V. 100 % duty solenoid so you can install it in series with the main battery feed to the car and use an on /off switch near you in the driver's seat to use in emergency

Morse cable on mine. The rest are just scrap tune and plate fabbed up. Lever is attached at the roll cage.
Doug

Here is mine.
[img]https://photos.app.goo.gl/VFBuwGRUvTSQNNxN6[/img]
[img]https://photos.app.goo.gl/qFMzRFDXnUtkmmcf6[/img]
[img]https://photos.app.goo.gl/ain4gp1kzJXuS7K17[/img]

I was going to look on Amazon or some local to get the button.I think I am going to use this fastronics 305-040 50 amp push pull button.17$

For those that run cables are those even legal? Have you ever had it commented on at tech? My NHRA rule book states all rod or cable must be of 5/16 diameter most of those look like 1/4 or less. Or is it the fact that the cable is just ancillary make it not relevant. I just looked at this rule for one of my cars I was working on a couple weeks ago. Using a shifter cable would be easier plus I have them laying around,but they aren't 5/16.

Mines never been questioned. Been running it 10 years at numerous tracks. My bet is the rod and cable are way stronger than the switch itself.
Doug

The rule book is concerned with safety people being able to shut everything down at the rear of the car, in the event of a crash.. Beyond that, they won't or shouldn't care.

If you back into a wall at speed and tear it all up, probably doesn't matter if you have a cable or rod at that point.

Dragsters have had the master switch up by the battery forever, with a cable to the rear of the car to operate it.

High amp remote relays are becoming common now with the pushbutton/mushroom head switches being used to control them. Takes some specific switches and wiring to be able to control it from 2 locations - unless you use your old master switch set up to control the relay, rather than to function as the high amp connector. Modern and Speedwire and others offer these systems.

Most of the shifter cables I have seen are only 3/16" (#10 threaded end), but the outside of the sheath may be 5/16 or 3/8". Many shifters are harder to move then the electrical main cut off switch.
The rule is the rule, I can't change that. IMO, a 3/16" rod 12" long is not stiff enough, but a 3/16" morse cable with thick outer sheath is strong enough (if I was making the rule).
A 30 series Morse cable has #10-32 ends
A 40 series Morse cable has 1/4" ends.

I like the comment about it being a secondary mechanism.

The older Mr. Gasket and Moroso battery cutoff switches weren't rated very high on much current they can safely handle, I wore one out and learned that they are rated less than 100 amps
There are better ones available, I bought one rated at 250 Amps and it worked great so can you find one to buy when you do a search
Sorry for no links or company names: blush:

My door car has one like Al's, except there is a parachute lever instead of a knob. Works great, and Tech inspector has not said a word.

The Moroso 74100 is no good. 20A continuous, 125A surge. The 74101 is the one to use, 175A continuous, 1000A surge,

Make sure the switch has silver contacts, which I believe the 74101 does. The Littelfuse/Cole Hersee 2484-16 is also a silver contact switch and is 175A rated continuous and intermittence rated 800A at 6VDC-36VDC, 15 On, 5 Minutes Off. Probably the one Moroso sells as the 74101.

These seem reasonably priced. A 43BC morse cable 6ft about $78.
A 30 series Morse cable has #10-32 ends
A 40 series Morse cable has 1/4-28 ends.

https://www.go2marine.com/Pro-X-43BC-Replacement-Control-Cables?quantity=1&length=1499

That's what i was thinking...as long as the mechanism out the back is 5/16 were good. I was just wondering if anyone got questioned over it.

Some people have used an air/CO2 with a Bimba cylinder to launch the parachute and that could also be connected to the shutoff turning it off at the same time.I will stick with the Ford relay and button to cut power and the main thing is to have it in a good place to de activate the power.

Damn, you guys have me considering adding one inside my car now. I have also done the dreaded sit down, strap in , hit the ignition switch and nothing.... have to unstrap , get out, turn it on at the rear and try again. lol.

The only time I would normally turn off the rear battery shut off switch was in the winter when the car sat in the trailer from October to April

Ford starter relays are for intermittent duty use. Solenoids used for a battery disconnect, that also carry the load of the car while running, need to be for constant duty use. They may look the same but they are not the same.

We use constant duty solenoids for control of "ignition on" circuits, typically 80 -100A rated, but they aren't designed to carry the in rush of a starter motor.

There are battery disconnectors/solenoids/relays made for this and designed to carry higher amperage and be in constant duty use.. But you can't buy them at an auto parts for $15.






250A continuous, intermittent well over 1000A

There might be motorhome solenoids with high enough ratings, if that is what a guy wants to use. Overall it might be a lighter system by a bit.

CM, i couldn't make out the complete tag on the solenoid you showed.
any chance you have a pic that shows the whole tag ? [TIA !]

I got the push switch from amazon and it is well made,no slop and I was thinking of mounting it on my shifter[PPP]