battery cut off switch

[magicmarto]

Hi All,
Happy Friday.
I am in the process of laying out my wiring harnesses. I am running a 5.0 Gen 2 Coyote motor.
This is kind of a weird question-I know what the battery cut off switch does.
Is it really needed? Or do guys install them for a extra level of security when the car is parked somewhere?


I've seen them under the dash, on the trans tunnel, behind the passenger seat, and on the back wall of the cockpit.


Let me know what you think on this
Thanks
Martin

[GoDadGo]

I installed the switch shown below in the transmission tunnel so I can kill the battery if I have any electrical issues....The key was just a security bonus (Feel Good For Me!) that may help with security, or not.

https://www.westmarine.com/buy/sierra--battery-switch-off-on--10529758?recordNum=8

Though I found similar looking switches at the local auto parts stores, the amperage ratings of those switches weren't even close to the Sierra Switch plus those others appeared to be rather cheaply made.

Good Luck From The Dark-Dart Side!

[Al_C]

I installed the FFR switch on mine. It's above the trans tunnel under the dash. For me, it was more about additional security than anything else. Lots of guys install these switches for racing purposes, but typically those are someplace where they can be easily accessed.

[MPTech]

I have the same one as GoDadGo. Couple advantages: theft security, electrical emergency, long-term storage (avoid draining the battery).

[swwebb]

I have the same one as GoDadGo. Couple advantages: theft security, electrical emergency, long-term storage (avoid draining the battery).

A lot of people have this switch, but then they add a "keep alive" bypass that keeps allows some power to bypass the cutoff switch for the clock, radio, and EFI. I went back and forth on adding this bypass and installed it originally. Then I decided I really wanted to kill all the power with the battery cutoff switch, so I took it out (actually just removed the fuse for now). I figured the EFI settings would not "go away", and I wanted to be able to use the switch to kill the power to work on the car.

[rychi1]

I installed one for two reasons: Safety and security. Mostly for the safety front so that as I am working on the car and before I have all of the wiring tied up I can cut the power when not in use.

[GoDadGo]

I've also got this switch:

https://www.amazon.com/Philmore-Switch-Lock-Removable-30-10078/dp/B00B7N8FOW/ref=sr_1_fkmr1_1?ie=UTF8&qid=1548438616&sr=8-1-fkmr1&keywords=philips+keyed+barrel+switch

installed inline with the clutch safety switch circuit.

The key is removed in both the On and Off positions.

[Railroad]

May sound crazy, but I put a heavy duty disconnect on the main power and used the one supplied with the kit on the "keep alive memory" wire. I can kill the mail power, which will not let the engine crank or run and still have the power to the ecu. If I need, I can disconnect the ecu power with the second disconnect. I put the main power switch on the back of the trans tunnel and the ecu switch inside the cubby hole behind the passenger. I should be able to reach through the hole and access the switch, if needed. I hope the ecu disconnect, keeps a clean connection. I guess I can just bridge it, if it becomes an issue.

[BEAR-AvHistory]

Have GoDadGo's red key switch wired with a 5amp self resetting keep alive circuit located on the U-Joint cover. Easy to reach & pull the key when you leave the car. If I only had the Coyote would have not bothered with the keep alive circuit but my other system for phone, music, maps would lose its mind.

Full electric kill to work on the car requires a battery cable removal.

[NAZ]

I only installed one as NHRA rules require it, otherwise I wouldn't have bothered. How many factory cars have you owned with a master switch? To me, it's just added expense and complexity. But many folks feel it's value added so use it or not -- your choice. It's not like you're going to void the FFR warranty if you leave it off.

[Dave Howard]

I installed the same switch as others with my Gen 1 Coyote. Put the switch on the back wall between the seats. It was an easy run since my battery was under the trunk. I didn't bother with the stay alive circuit. I know....you lose any self tuning and learnjng. After 40,000 kilometers, the car runs great. My intention was to have 100% electrical shut off.

[Itchief]

Martin

When I build the car I didn’t install a battery cut off switch my though was I don’t plan on racing so why would I need a cut off switch. To make a long story short one day the starter bendix got stuck and the only way I could stop the motor was to remove the negative battery terminal cable once I got back home.

I added the cut off switch between the seats at the same time I replaced the starter

Rick

[CraigS]

I had the usual cutoff switch in the trunk for about 5 years. Used maybe 3 times. When I moved the battery to the front I did not install a switch. Mainly because I hadn't used it enough to bother. But also because as a lexus tech, w/ the ever increasing number of systems w/ memory, we had all started replacing batteries w/ the engine running so we didn't have to reset everything. From that I realized that the switch would not shut off a running engine. It's been 5 years w/o the switch and I have yet to miss it.

[magicmarto]

Thank you to all
After all the input and talking to a few local Roadster owners, I am going to pass on the batter cut off switch-I don't plan on racing it. I will do a few autocrosses.
Thanks again for all the input fellas . Have a great week
Martin

[Ducky2009]

There are a couple ways to wire the cutoff switch. One is to kill ALL power. If you plan to use on a daily basis, killing all power will kill you clock, radio memory if you have a radio, and your ECU. The ECU has a learning mode, making adjustments to engine tuning, and retaining settings. If you kill the power, the clock and radio will need reset constantly. The ECU will re-learn.

If you plan to race, it may be required to have a cutoff switch, depending type of racing.

[Dewey McBride]

I have a hidden switch linked to my clutch. If I flip it, it bypasses the wire that tells the ECU that the clutch is engaged, and it won't start. I also have a battery cut off in the trunk for long term storage.

[GTBradley]

I wanted a spare key for the Hella battery cut-off switch and thought I would post it here in case someone else needs it:

HELLA 706729011 Replacement Key for Battery Master Switch (https://www.amazon.com/dp/B000N9RXOO/ref=cm_sw_r_cp_tai_Aaf8Db82B70TR)

118862

[magicmarto]

Does anyone know where to get a spare red key for the Hella switch. just in case you loose the original
M

[Railroad]

I think the Harbor Freight disconnect is the same, if you have to buy the whole switch.

[Avalanche325]

Summit Racing
https://www.summitracing.com/parts/hla-706729011

I keep a spare hidden in the car.

I have one of these for my keys and disconnect. Got it at Home Depot.

118790

[Papa]

Does anyone know where to get a spare red key for the Hella switch. just in case you loose the original
M

That's what GTBradley provided a link for in post #17.

[GTBradley]

I received the key tonight and can confirm it does work in the FFR supplied battery cutoff switch.

[Jeff Kleiner]

I wanted a spare key for the Hella battery cut-off switch and thought I would post it here in case someone else needs it:

HELLA 706729011 Replacement Key for Battery Master Switch (https://www.amazon.com/dp/B000N9RXOO/ref=cm_sw_r_cp_tai_Aaf8Db82B70TR)



Or if you're cheap like me you can go for the 68 cent variety ;)

https://www.ebay.com/p/12010304377?iid=142781457612&chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=142781457612&targetid=484372122679&device=c&mktype=pla&googleloc=9016564&poi=&campaignid=8080423831&mkgroupid=86416348947&rlsatarget=pla-484372122679&abcId=1139446&merchantid=109537348&gclid=CjwKCAiAis3vBRBdEiwAHXB29Ez2UW4paLXpV0O6Tfzn rFmVcItxKsn3ZleHu_8pitvtjPyvsX2YnBoCcMoQAvD_BwE

Cheers,
Jeff

[Papa]

Or if you're cheap like me you can go for the 68 cent variety ;)

https://www.ebay.com/p/12010304377?iid=142781457612&chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=142781457612&targetid=484372122679&device=c&mktype=pla&googleloc=9016564&poi=&campaignid=8080423831&mkgroupid=86416348947&rlsatarget=pla-484372122679&abcId=1139446&merchantid=109537348&gclid=CjwKCAiAis3vBRBdEiwAHXB29Ez2UW4paLXpV0O6Tfzn rFmVcItxKsn3ZleHu_8pitvtjPyvsX2YnBoCcMoQAvD_BwE

Cheers,
Jeff

Jeff, you may be "cheap", but you do good work.

Dave

[GTBradley]

Or if you're cheap like me you can go for the 68 cent variety ;)

Cheers,
Jeff

Jeff, your timing is impeccable.