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Technical Battery kill switch

Discussion in 'The Hokey Ass Message Board' started by bill mat, Jul 9, 2021.

  1. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

    Is it possible to use a continuous solenoid and a toggle switch for a battery disconnect? I want to put a toggle switch on the dash of my Studebaker that would disconnect the battery power . Thanks for any information.
     
  2. oldolds
    Joined: Oct 18, 2010
    Posts: 3,587

    oldolds
    Member

    Can you do it? Yes. Should you do it? No. If you want the battery disconnected it should be disconnected. No electronics involved.
     
    impala4speed likes this.
  3. SEAAIRE354
    Joined: Sep 7, 2015
    Posts: 552

    SEAAIRE354
    Member

    I’m not aware of anything like this in the automotive world but it’s very common in the marine world. There are several different types. Some have a mechanical override in case of a failure in the switch so it can be turned back on. Now come to think of it I’ve seen it in the fire truck industry. Just get something that’s purpose built and rated for your application. Most starter solenoids are not continuous duty.
     
    Boneyard51 likes this.
  4. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,213

    Elcohaulic

    I agree with oldolds. What happens if the electronics decide to act up, like they usually do, when your out in heavy traffic with no were to turn off the road.. The less electronics, the less problems and the more fun you will have with your car..

    I would get a battery disconnect knife switch. I have the screw on disconnects but like the knife switch better. The little green screw disconnect doesn't look like it could let 100+ amps pass thru it when the starter motor is ungauged.. I had one on my 454 and was getting hard starting when hot. I removed it and the starter worked like it was brand new.. I put knife switch on and it starts just like it did with no switch..
     
  5. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

     
  6. jnaki
    Joined: Jan 1, 2015
    Posts: 10,984

    jnaki





    BATTERY KILL SWITCH

    Hello,


    A battery kill switch had one outcome for us as teenagers. It was a low cost theft deterrent on our hot rods and cruising sedans. A friend who worked at a small dealership told us that those dealers would install a version of the battery kill switch for the most popular models, or those that had the high possibility of getting stolen. When the switch was turned on or in this case, off, the car could not be started anytime on the dealer lots or street locations.

    But, the switch was hidden under the dash with only the dealer/salesman/ and when anyone bought the cars in question, were asked if they wanted that switch still installed. There were no bells and whistles, or off kilter loud alarms, just a dead car sitting on the parking lot or street.

    It did help as a sales tool, was low cost as an extra and worked to deter a quick theft. Usually when the old ignition switch wires were crossed and attached, the car started. The hidden battery kill switch did its intended job. But, whoever drove the said car/hot rod, they had to know about the hidden switch.

    Jnaki

    Note: it had to be hidden away from prying eyes and errand feet/knees, etc. Then later on, dealers had access to these strange key cards they inserted into an almost hidden outlet to gain access to starting the car. It was their version of dealer lot theft security. Those were taken off before the sale to any customer.

    Unless you are installing a battery kill switch for theft deterrent, the switch should be out of sight. Not on the dash. YRMV
     
  7. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

    I was a fireman for 35 years and originally the trucks had a heavy duty switch with on,off ,battery one and battery two on them. Towards the end of my career the trucks just had a toggle switch on the dash. Not sure if the switch went to a solenoid or something else.
     
  8. Petejoe
    Joined: Nov 27, 2002
    Posts: 12,541

    Petejoe
    Member
    from Zoar, Ohio

    I installed a kill switch through the floor and under the seat behind my feet.
    Easily accessible, no solenoid involved and can be operated from the drivers seat.
     
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  9. squirrel
    Joined: Sep 23, 2004
    Posts: 59,180

    squirrel
    Member

    Do you mean a relay, instead of a solenoid?

    A solenoid moves something. A relay switches an electric circuit.

    (stupid semantics, but if you're looking for parts, using the correct name for it can actually be helpful)
     
  10. I hate to point out the obvious, but if you use it as a battery kill switch, you won’t have any power to close the solenoid when you want to turn the power back on. You would have to run a separate power wire to your toggle straight off the battery to accomplish this. Don’t forget to fuse that separate wire.
     
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  11. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,441

    Ebbsspeed
    ALLIANCE MEMBER

    The concise answer to your question is "yes". When you get into the heavier current "relays" they are usually referred to as contactors. Here's a continuous duty one rated for 225 amps with a surge of 600. If there is a concern that the starter might chew one up then put two of them in parallel.

    There are other wiring options that leave the starter connected (because in essence it has it's own contactor that is normally disconnected from the battery) and routes the rest of the power through the dash switch controlled contactor.

    https://www.waytekwire.com/item/804...4tXgAtOY5yHYnmQ8aHFIIYmHX30r7QoBoC5M8QAvD_BwE
     
    Last edited: Jul 9, 2021
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  12. Joe Blow
    Joined: Oct 29, 2016
    Posts: 1,604

    Joe Blow
    ALLIANCE MEMBER

    I put a standard heavy duty disconnect on my dash....within easy reach in my A coupe. Found an old 50's boat Sudbury Laboratory circuit breaker switch and used the face plate. Also the arm off a vintage toggle switch. Looks vintage in the front but all business out back.

    DSC01109.JPG DSC01111.JPG
     
  13. Friend of mine installs a relay/solenoid. You touch a button on the dash it switches off. Touch it again it switches on. He buys them at an electric supply house. Switch is used to ground the solenoid that causes it to work
     
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  14. Last edited: Jul 9, 2021
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  15. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

  16. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

    This is what I was talking about. The picture above. I would put this between the battery and cable. Run power from the battery to a switch then a wire to the solenoid or relay. I always thought a solenoid was a kind of relay but I may be wrong. I am thankful for all the responses. Everyone are always helpful here. Can the switch be a toggle or does it have to be a momentary on switch?
     
  17. MeanGene427
    Joined: Dec 15, 2010
    Posts: 2,307

    MeanGene427
    Member
    from Napa

    An easy deal, and fairly secure, is a plain CAT master switch. The drag race type switches with a handle are similar, but the CAT switches have a removable key, so if it's hidden, pretty secure. Very high capacity and very durable, all power on a D11 runs through it. Installs on the negative cable, and easy to hide. There are many aftermarket "replacement" switches, but be careful, most are inferior
    https://shop.cat.com/en/usa-parts/7N-0718
     
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  18. unfinished
    Joined: Jan 8, 2020
    Posts: 127

    unfinished
    Member

    EVERYTHING that gets parked in my shop has a battery cutoff or I just pull the negative cable off the battery. Several years ago I was spotting in a few places on a rather nice, original 65 Ford Galaxy. The car was in my shop less than a week. A couple of weeks after the owner picked up his Galaxy some sort of wiring short burnt the car and his shop down. All my cars now have a battery disconnect!
     
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  19. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 33,531

    Jalopy Joker
    Member

    why do you need a battery disconnect staring you in the face? have that many complications with existing wiring? or just want a theft prevention type switch? one easily accessed under hood or under car should work fine if want to stop battery drain when not using ride for long periods of time - if you have battery drain there is another problem to address
     
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  20. JWL115C
    Joined: Jan 28, 2010
    Posts: 288

    JWL115C
    Member

    I have a heavy duty mechanical battery cut off switch mounted on the partition between the passenger compartment and trunk in the passenger compartment side. Easy to get to, but not obvious. I have been told it is better to attach the switch to the ground circuit rather than the hot side. Either will work, but the grounded side is safer. I also have a fuel line shut off valve on the fuel line where it comes out the top of the tank, which is mounted in the trunk. This valve came in handy when there was a fuel leak when the car was in the garage. I thank the builder for providing both of these safety items. Finally, I have mounted a fire extinguisher on the floor behind the seat on the driver's side. Easy to get to just in case. The car is a 32 three window coupe.
     
  21. These are one of those items that really only has specific applications, none of which apply to 'normal' street-driven cars. Detroit has sold literally millions of car without them. If you're doing it for 'safety' reasons, I'd suggest installing as per NHRA rules as a hidden switch is useless to a first responder. If it's a current drain issue, you have electrical system issues that should be addressed. As a theft deterrent, there's easier ways to do this that would be just as effective. In most cases you're just adding another failure point.
     
  22. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,232

    Mimilan
    Member

    @bill mat
    Just use a Ford starter relay mounted close to the battery for the starter circuit [and bridge the solenoid on the starter]
    That way the H/D cables are dead as a dodo unless you're cranking the engine.
    Here's a Schematic of how we did this on our Race Car [up to FIA standards]
    upload_2021-7-10_9-23-37.png
    Note: we used a blocking diode on the charge circuit because we're always tinkering in the engine bay.


    Then you can use a 80a [max] SPDT relay to power the rest of the car.[where the "Isolator switch" is in the above schematic]
    upload_2021-7-10_9-16-45.png
    With the SPDT relay you use post # 30 from battery
    Post # 87 goes to the main harness
    Post # 87A goes to any memory circuits eg: Stereo or Clock
    [then bridge post 87 to post 87A with a blocking diode of approx 3a between them]

    That way you can disconnect the whole system and not lose clock or radio memory

    All you need then is a low load switch to power up Post# 85 or 86 [one being grounded]
    A simple latching [press on /press off] button would do that.
     
    Last edited: Jul 10, 2021
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  23. Mr48chev
    Joined: Dec 28, 2007
    Posts: 35,546

    Mr48chev
    ALLIANCE MEMBER

    Why is it that every time someone comes up with very simple question folks have to throw out opinions rather than honest answers.

    The simple freaking answer is yes it is possible with a continuous duty solenoid that will handle enough amps to run the starter. These are used on most RV setups with separate batteries for the coach so they don't drain the main battery running accessories.

    Simply wire the continuous duty solenoid's switch and trigger post with totally separate wires from the battery and back to the solenoid.
    Hide the toggle switch so that it is easy to reach unobserved but not out in a visible spot.

    If you just wanted to do an anti theft when parked the Ford Solenoid wired into the starter cable with a hidden push button to operate it when you turn the key would work. The lights will work, the horn will honk but when you turn the key the starter won't crank until you push the button again this one should be hidden but easily reachable with your non key turning hand. It just makes starting the car a two handed operation. With that it would be best to hide the Ford Solenoid somewhere though. In this case it doesn't have to act as a hot start mode unit but if you hook it up per the diagram that Mimilam showed it won't hurt anything. You just don't connect the start wire off the ignition switch if you do that.
     
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  24. SS327
    Joined: Sep 11, 2017
    Posts: 3,614

    SS327

    Look to the Rv industry. When I worked at Coachmen we had a setup like that on the class A and C motor homes. Also seen it used on busses.
     
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  25. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,396

    gimpyshotrods
    ALLIANCE MEMBER

    I just forget to turn my lights all the way off.

    It does not take all that long to kill the battery, and the headlight switch is already installed.
     
  26. Marty Strode
    Joined: Apr 28, 2011
    Posts: 9,582

    Marty Strode
    Member

    Cole Hersee 24200, a latching solenoid that wires into the positive cable. Only a small ground wire required, to a push button, anywhere you want it. Push the button once, power on, push it again, power off. IMG_0671.JPG
     
    Just Gary, uncle buck, SS327 and 5 others like this.
  27. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,232

    Mimilan
    Member

    Use a 2 wire piezoelectric buzzer and wire it between the taillight circuit and the ignition circuit
    The piezo buzzer works like a diode, only passing current in one direction. These will then be polarized, so you have to connect the positive wire to the battery side.

    Connect the piezo buzzer between the ignition switch output [neg - piezo buzzer wire] and the lighting switch taillight output [pos+ piezo buzzer wire].
    Switch on the lights. If it doesn't buzz, swap over the wires on the piezo buzzer.

    With ignition and lights on at the same time the buzzer has 12 volts on both sides, will pass no current, and will not sound.

    With ignition switch on but no lights, the piezo buzzer has 12 volts on one side but will not pass current in that direction, so also does not sound.

    With lights on and ignition switch off, the piezo buzzer gets power from the lighting circuit and finds ground return through the oil sender, fuel pump or gauges.

    The piezo buzzer has such high internal resistance (only a 10mA device) that the lower resistance circuits conduct current like ground connection for the buzzer.

    Current is limited to 10mA by the buzzer, so nothing happens in the ignition or fuel pump or fuel gauge (or heater fan, wipers or radio if any of those were left on). The little piezo buzzer could buzz loudly for 3 months and it still wouldn't flatten the battery.
     
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  28. bill mat
    Joined: Jul 1, 2017
    Posts: 45

    bill mat

    Thanks again. My main idea is to just not have power running to old wiring constantly and to achieve this without having to disconnect the cable every time. At some point I think I will rewire the car but not right now. I will either put disconnect switch at the battery or use the solenoid idea. While differing opinions due tend to get confusing I do appreciate them. I have been helped numerous times on this site. Being a beginner (a 62 year old beginner) it is extremely helpful to sometimes run my ideas by experts. Thanks again
     
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  29. Elcohaulic
    Joined: Dec 27, 2017
    Posts: 2,213

    Elcohaulic

    Just put a knife switch on the batterys negative terminal. You could run a choke cable to the knife to open and close it. Make sure the cable isn't grounded!
     
  30. Once again, Marty’s the Man! Simple solution and elegant in execution. And if you keep a 1/2” combination wrench in the glovebox you can just move the hot lead to the input side if the solenoid failed while on a road trip so you can get home! One more for my brain to remember….
     
    Boneyard51 likes this.

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