Re: Master Cutoff Switch
 

General: 8.4 Mandatory when battery is relocated or as outlined in Class Requirements.


Check the current class rules for your car. My guess is yes. Battery in trunk = rear deck mount cut off.

Re: Master Cutoff Switch
 

I thought that at first, but I'm not re locating. Just adding

Re: Master Cutoff Switch
 

Jeff,
You do need a cut off switch at the back of the car since you are putting a battery in the trunk.

Raul

Re: Master Cutoff Switch
 

It's just a switch.... Unless you are adding under the hood, put it in.


A stock battery location is under the hood. Install one anywhere else and a cut off would be required. When the battery is under the hood the power usually runs to a distribution block under the hood keeping the feed short and contained. When you add/relocate a battery in the trunk, you have 10-15 feet of vulnerable wire running under the car. The cutoff switch is meant to do two things, kill ignition and fuel pump power (fire control) and prevent any pinched or cut wire from shorting the chassis and blowing the whole friggin' car up with you inside.


Disclaimer: I am a bracket racer. I have a full cage, window net, neck collar and fire extinguisher in my 12 second car.



Anyone know the kill requirements for electric vehicles? Jeff Lane, you out there? I'd ask Garlits but I don't think he's around these parts much.

Re: Master Cutoff Switch
 

Yes! And if you want to wire this car "correctly" you will need a large constant-duty relay under the hood to disconnect the front battery from the rear switch........ Pain in the butt and extra cost, but well worth the hassle. I did an NHRA Stocker like this, the only "issue" is you need to remember to turn the main power off, especially after you put the car in the trailer. That constant-duty relay pulls a decent amount of power and will drain your batteries.........

Now, back to the battery location issue. I have a 2008 Buick Lucerne, stock battery location is under the rear seat. My 2015 Camaro has the battery in the trunk, from the factory, so do the newer Vettes.

These batteries are no relocated, wonder when the NHRA will start looking at these vehicles and making people put a switch in the rear of the car.

And what about those electric vehicles............

Re: Master Cutoff Switch
 

It's sort of a side step instead of a total thread derail, but I'm pretty amazed that no one seems to be concerned with batteries in electric cars.


Ever seen a vid on Youtube where some idiot shorts the battery of a vaping device and it goes into thermal runaway? Hellfire and carnage results.


Teslas use the same battery. But they have 8000 of them in their battery packs. Haven't heard a peep from the NHTSA, nor DOT for that matter.

Re: Master Cutoff Switch
 

I'll take a shot at answering the master cut off switch for electric vehicles question.. Jeff, team and I built the eCOPO as well as the orange car "Shock and Awe" that has run around division 6 for a few years.

All our cars, per General Rule 8.4, have master cut off switches. They are push off and clearly marked. When pushed they remove all low voltage power to the rest of the car (including to the low voltage components that connect the high voltage to the propulsion system).

We also have an "oh-sh#*" switch on the dash, that if ever needed (hasn't been needed in almost 175 electric runs) would remove 12v power to the master contactor in the hv motor system. That too is push off. That does not remove 12v power from the entire vehicle, just disconnects the HV.

Here's a picture of the back of the orange high school car.....
Pat

Re: Master Cutoff Switch
 

Thank you for the answer. In regards to the questions about EV cutoffs from others, the rule book has cutoff switch requirements. It must disconnect the motor and power pack. It's in the EV section buried up with ET Snowmobiles.

Re: Master Cutoff Switch
 

It is worth mentioning that the cutoff is supposed to be on the Positive side. If you have it the other way and crash and fold the quarter panel into the Negative terminal the switch won't work,
The rules are written in blood as they say.

Re: Master Cutoff Switch
 

I’ve decided to run a switch even though I don’t plan on putting a battery in the truck just yet.

My question is about the wire from the alternator, can it run to the battery or does it need to be run to the switch?