Author Topic: battery kill switch question  (Read 19594 times)

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Offline Slide

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battery kill switch question
« on: August 03, 2016, 01:23:35 PM »
Hey guys,

My rule book is with my car which is at the cage builders. The cage builder is out racing and wont be back for two weeks. I am trying to get a battery kill switch set up for the drivers compartment.

I am looking at the following type of cut off. I like the button idea as it is different than the pull switch for the fire system. I believe that the pull switch and the regular red turn key look too similar and may get in each others way if I am going for one and not the other or some such nonsense.

Remote Disconnect w/Emergency Button
http://www.painlessperformance.com/webcat/30205



The car will "hopefully" run in one of the upcoming mojave miles and mile and a halfs... and then in a shift sector airstrip attack half mile...and maybe a texas mile if timing all works out.

But the car is really not, actually its not built to be competitive in any class, I have just built it, or rather building it, for fun with parts that I want...(which puts it into all sorts of screwy classes if I were to get to technical!)

Anyways, can anyone see a reason, that if I were to be in the 200 to 205 mph arena, be stopped at the inspection phase for this type of cut off? The button is what I think makes it not nhra approved vs a key style switch....

Offline RichFox

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Re: battery kill switch question
« Reply #1 on: August 03, 2016, 01:52:11 PM »
At least for SCTA events, the switch is mounted outside where it can be accessed by safety personal in case of an accident in which you are disabled. For other organizations the rule may be different.

Offline Slide

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Re: battery kill switch question
« Reply #2 on: August 03, 2016, 03:13:27 PM »
I was planning on justo side the window. So reachable by driver and safety personnel.

Offline kiwi belly tank

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Re: battery kill switch question
« Reply #3 on: August 03, 2016, 03:21:55 PM »
Has to be on the front or rear of vehicle.
If you have a "one wire" alternator this won't kill the engine as the alternator will feed the system with the battery disconnected.
  Sid.

Offline wheelrdealer

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Re: battery kill switch question
« Reply #4 on: August 03, 2016, 03:39:56 PM »
Slide:

I like that set up looks like it could be installed in a neat and clean way. To satisfy the rules. I built a push off knob at the left rear and then used a teleflex throttle cable to connect a linkage to a handle and knob in the driver's compartment. I use all relays and do not have any high amp circuits inside the driver's compartment. The parachute handles pull to the rear while the in-car master electric cut off pushes  forward. Other than the mounts, I fabricated a new lever for the battery on/off switch so it is pretty easy to make. I started to make cutoff from an electric door lock actuator but then decided against electric and used a linkage. I did not want a blown fuse in the electric cut off to prevent me from cutting all power from inside the car. I figured once the car starts rolling over it is plausible that damaged electrical connections could ground and start popping fuses.

I am a backyard non-professional fabricator so this is just my 2 cents.

Good luck with the build.

BR
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Offline Slide

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Re: battery kill switch question
« Reply #5 on: August 03, 2016, 05:48:47 PM »
Wheelrdealer and kiwi belly tank: Thanks for the info guys I appreciate it! We have an idea on where we need the electrical break to be, we just aren't sure if any of the ruling bodies would have a problem with the push button style.

I plan on having a second switch, more than likely a standard key shape, that is directly in line so there is a back up. But for the one that is driver accessible (and potentially the one that satisfies the safety worker accessible in the same part) I'd like and am willing to have a remote switch to.

Offline RichFox

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Re: battery kill switch question
« Reply #6 on: August 03, 2016, 06:31:32 PM »
You can do whatever you want on the driver cut off. The safety requirement wants a clearly marked outside switch or push button. Usually on the left rear somewhere. You need to look at the rule book again.

Offline Slide

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Re: battery kill switch question
« Reply #7 on: August 08, 2016, 09:50:30 PM »
Thanks. Rule book is still with cage builder....

Ordered the cartek xs so I can run push buttons and kill battery as well as ecu with out issue.

Little pricey but light and does the job. No parts to get stuck or break....I hope.

Offline lecran

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Re: battery kill switch question
« Reply #8 on: June 26, 2017, 04:47:46 PM »
Thank you for your advices! There are very useful!
I really like to drive my car. I can have a rest from all problemes and troubles. I can just press the Play Button on my sound system and relax...

Offline manta22

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Re: battery kill switch question
« Reply #9 on: June 26, 2017, 05:08:32 PM »
Slide;

My battery cut-off switch is a Moroso rotary knob on/off switch mounted to the chassis. I replaced the knob with a lever arm that is connected to a push-pull cable that comes out the front, on the side of my radiator air intake. Also connected to that lever is a short rod that comes into the cockpit through a support bushing. A round knob on the end of the rod also allows the battery to be switched on/off by the driver.

In addition to the battery cut-off switch, I have a very high current relay that supplies power to everything but the starter motor. A toggle switch with a spring-loaded red cover is mounted on the instrument panel, allowing the driver to quickly shut off power with a swipe of a gloved hand. There is a G-switch in series with the relay coil so an impact will also shut off the 12V DC power.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ

Offline jacksoni

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Re: battery kill switch question
« Reply #10 on: June 26, 2017, 06:02:23 PM »
As Neil suggests, at least for SCTA and ECTA (you need to check rules for the other organizations) you need an inertia type cut off switch for an electric fuel pump, regardless of other battery cut off switches. In a prior car I had a Moroso type switch for the driver as well as one outside to meet the safety requirements. I think this is at least in part what you are asking. Stuff may happen suddenly so you might not have time to shut things down.
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Offline olepaw

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Re: battery kill switch question
« Reply #11 on: June 27, 2017, 07:30:30 PM »
We have a cutoff at back of car,rollover for fuel pump and one within reach of driver. WE are into safety. Cheap investment.
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Offline ETM

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Re: battery kill switch question
« Reply #12 on: September 11, 2017, 03:45:52 PM »
A relay/solenoid electrical cutoff is nice because it allows any number disconnects
to me located wherever you like them. A single lead being grounded triggers
the solenoid to then power the car. That lead can go thru a NC switch for the safety
crew, NC shock/rollover sensor and finally to the drivers master switch.

The trick is to isolate the ignition from the alternator. To do so use two relays
mounted side by side next to the battery, both triggered by the same ground signal.

The first is of the high amp variety like the one pictured above. Its output feeds
the starter solenoid.  The alternators output is also connected to the starter solenoid
feed. This is the path used to charge the battery.

The second is a typical 40 amp relay that feeds the ignition system and/or fusebox.


Offline kiwi belly tank

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Re: battery kill switch question
« Reply #13 on: September 11, 2017, 06:29:24 PM »
The problem using a ground switch to a relay is if that circuit rubs a short to ground you now can't shut it off. If you switch the power side & you have a short it pops the fuse & shuts it off.
Easiest way with the charging system is don't use a one wire self exciting alternator, use a field excited alternator so when you kill the battery you kill the alternator.
  Sid.

Offline ETM

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Re: battery kill switch question
« Reply #14 on: September 12, 2017, 05:15:08 PM »
If concerned about a fault rubbing the circuit and keeping everything on, it is just as easy to trigger the
relays high-side instead as low-side.  You just run the fused loop thru the switches and permanently ground
the opposite terminal.

Alternators that will keep the engine running are not limited to the single wire variety.  Two wire Bosch, Delco
and Nippondenso  (Denso) units that I've worked with won't.  Only some of the newer style systems with
separate switched power and sense wires can recognize the battery disconnect and shut down.  So don't
assume, test.  And test at a decent RPM. I've seen cars pass the battery cutoff test at idle due to low alternator
output (underdrive) but continue to run when RPMs are elevated.