Solid state Master cutoff switches instead off the old style master cutoff

Discussion in 'Road Racing Forum' started by Budget Boss, Nov 3, 2014.

  1. Budget Boss

    Budget Boss TMO Advanced

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    Well I had the solid state master cutoff switches installed in my car instead of the old school cutoff switches. The solid state are remotely controlled from the driver's compartment and from outside of the car. After I got my car back I was having problems starting the car. I thought it might have been because we removed the safety restraint module out of the car. So, we put it back in and the car started a little better.

    I was at ECR this past weekend for a NASA event. I was able to start the car and pull it out of the trailer. However, after that I couldn't start the car without a jump. After I got a jump and the car was running the new Solid state master cut off switch caught fire. I grab what I thought was a halon fire extinguisher, it ended up being aquas fire extinguisher, and killed the power at the master inside the car. Go back to the trunk of the car where one of two solid state master control cutoff switches are on fire and tried to put it out. No good still on fire. So, I disconnect the battery while the fire is still going. I was lucky that the guy next to me had a halon fire extinguisher to put the fire out.

    So, does anybody use solid state cutoff switches? Have you had good luck with them? If so, what brand? If you don't or do like them and the reasons why?

    Sorry for all the questions. I want to know if I should remove the solid state cutoff switches and replace them with the old style switches which is what I wanted in the first place. I would be willing to keep the solid state if I was sure they were not going to catch fire again. Thanks in advance.

    [​IMG]
     
  2. Roadhouse

    Roadhouse Logan

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    Wow...sorry to hear about the fire, Jamie. Hopefully there was little or no damage.

    I don't have any input on the matter but plan on using a traditional cutoff switch in my car. Good luck and keep us posted.
     
  3. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    WOW that is not good!

    I use a SS cutoff in my car, but my kill switch is not a traditional "battery disconnect" switch--mine shuts down the vehicle by killing the PCM power feed. There is a LOT less current to manage with this method. No issues whatsoever with this method's functionality or compliance.

    A true battery disconnect isn't required by NASA regulations for for ST1-2-3, only for Super Unlimited.
    Read the regulations carefully if you're concerned about this.

    Just something else to consider. Hope you and the car are OK after all of this.

    If you like, I can take a pic of the relay we used, my builder uses this method (PCM kill) in most of his builds and same for these relays. Nothing much to look at, but they work (although there should be some wear out over time/long-term use).
     
  4. WinterSucks

    WinterSucks TMO Addict

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    As an EE I would MUCH prefer a beefy mechanical switch. Solid state devices can fail shorted and should not be trusted, IMO. If you want a remote control of the main power coming from the Battery you could use a big honking contactor or relay.
     
  5. Budget Boss

    Budget Boss TMO Advanced

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    Drew,

    That makes more sense than hooking it up to the battery. Because I had to jump start the car there would be a lot more current (batteries in parallel equals more current) and that may have over loaded the SS. I'll have to take a look at the rules. I wanted to be able to switch to AI in the future, so that May have been the reason for the switch to cutoff the battery.

    I have decided to change to mechanical switches. Less chance of electrical fire. By less I mean not at all using mechanical switches. The whole reason for making this car a sound racecar was for safety and fire isn't safe. Thanks everyone for the input. Drew maybe next time I'll go with SS hooked up to the PCM, but that will be on a Miata because Mustangs are expensive ;)
     
  6. Budget Boss

    Budget Boss TMO Advanced

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    Very minimum damage. Mostly to the SS module.
     
  7. blacksheep-1

    blacksheep-1 TMO Addict

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    A little off topic but bear with me, I have 32 years of experience with St. Pete, FL FD and have run the city's portion of the pit fire crews since the St. Pete Grand Prix first started in the mid 80s. FWIW, I much prefer an AFFF extinguisher over anything else, the halons work OK and don't leave a residue but if the object is still hot and their is fuel around it could easily reignite..and often does. The dry chem can work on everything electrical to fuel to magnesium (depending on the type) but are acidic in nature and will cause all sorts of problems with the electrics. While the AFFF can't be used on electrical fire (house current and above) it can be used on vehicle electrical and fuel fires. since it is mostly water the residue can easily be cleaned up and it has the advantage of covering a fuel fire and preventing re ignition.
    For everyday use in my garage I keep and old school water extinguisher that you can fill up yourself and charge with an air compressor, except I add a product called Cold Fire..which basically breaks up the water droplets, lets the water soak into upholstery and it also has a positive effect on fuel fires.

    Here's the fire extinguisher you are looking for, try to find the older ones with the schrader valve in them so you can fill them from a tire chuck, if you can't you will have to cobb together some adapters to "back fill" it through the nozzle end (it unscrews, just read the pressure gauge to see when it's full) You can find these extinguishers all over the place in surplus so don't buy a new one...say 25 bucks should do it and don't get the old ones with a riveted seam. I keep one within arm's length whenever I'm welding.
    Link:http://www.amazon.com/Kidde-466403-Extinguisher-Gallon-Stainless/dp/B001ECQ5M0

    and the additive
    link:http://www.coldfiredirect.com/Cold-Fire/?gclid=Cj0KEQiA1eyiBRC-qI2VzKf0vaUBEiQAUiZ3xKtdpHRyiQq2SvIDJjF-MzyLiImhIDnvceKvKwj2zygaAkgW8P8HAQ#

    You can also use AFFF in this extinguisher and although AFFF is expensive your local FD can probably let you have some residual out of an open container, you only need about 10-15% for the 2.5 gallon extinguisher..whatever that comes out to, so it's not much, we used to keep all of our extinguishers on pit road exactly like that.

    This has been a Blacksheep-1 public service announcement now back to your regularly scheduled posting
     
  8. WinterSucks

    WinterSucks TMO Addict

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    I hope you can get the stank out of the car... I hate that smell.
     
  9. ls110

    ls110 John

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    Drew - Can you tell me the what master switch you installed? If you had a part number that would be great. Planning to do this install to be NASA compliant.
     
  10. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    The switch itself and cover are Carling stuff from Pegasus. Since it's only controlling the action of the SS relay, it doesn't have to handle a ton of current. I also use these for other things in my switch plate like AIM system on/off etc.
    https://www.pegasusautoracing.com/productdetails.asp?RecID=4657
    https://www.pegasusautoracing.com/productdetails.asp?RecID=1463

    My fabricator installed the SS relay, I don't know much about it, but it is one of these (not sure if it is a grounded type or insulated type):
    http://www.colehersee.com/home/grid/cat/187/
    http://www.colehersee.com/home/grid/cat/186/

    Here is a picture installed in the vehicle:
    [​IMG]

    It is inline with the main power line from the battery positive terminal to the engine bay fuse box (interrupts a fairly large wire, looks like 0-gauge or something). Controlled by the small wire on the front which is the switch inside the car.
     
  11. ls110

    ls110 John

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    Thanks for all the info Drew. I like the approach of the low current switch and plan to put this in place.
     
  12. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    Right on. Just make sure your rules say "kill switch" and not "battery disconnect".

    You can see the arrangement and positive action of these switches here in this video: https://www.youtube.com/watch?v=BckjSWfdhf0
     
  13. ls110

    ls110 John

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    The vid is helpful to see your switch panel. As I am planning to do the W2W in NASA, it is the same rules you are planning by. Will double check it however. Did you custom make your the panel yourself or buy a 3rd party panel? I currently have a blank panel that I made.

    Seeing your AIM makes me wish I had gone that path instead of TraqMate. I have used a friend's AIM for a few events and it collects much more data.
     
  14. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    The panel is from Watson Racing. Didn't want to mess around with the fitment and curvature myself and they had one of these ready to go.

    If you are running ST1/2/3 and/or TT1/2/3 the kill switch is fine, only Super Unlimited /TTU requires a true battery disconnect. But do read up just in case.

    The AIM is a valuable resource on and off the track. I picked mine up used--you might be able to do the same if you keep your eyes peeled.
     
  15. ls110

    ls110 John

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    Looking at the vid again of your interior, how do see the fuel gage? Your AIM appears to be slightly larger than my TraqDash.
     
  16. ArizonaBOSS

    ArizonaBOSS Because racecar. Moderator

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    I don't. It's irrelevant on-track anyways. But you have to understand how much fuel you're going to burn each session. If I'm running a 45-minute race, the car has to be totally topped-off to make it. Otherwise normal burn rate is about 4 gal/20 min.
     

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