solder_guy Posted January 27, 2008 Share Posted January 27, 2008 This is the same Battery Cut-Off Switch that I installed in the dash of my Rotus. Works great! Current sale price is right! $2.99 I may get another to have some extra keys. Rob http://www.usa7s.com/aspnetforum/upload/1973038830_battery.gif Link to comment Share on other sites More sharing options...
slngsht Posted January 27, 2008 Share Posted January 27, 2008 damn! I never thought to look at harbor freight for a battery cutoff switch. Good find. Hopefully the harbor freight version won't catch on fire and burn the car down. :jester: Link to comment Share on other sites More sharing options...
Kitcat Posted January 27, 2008 Share Posted January 27, 2008 Just ordered two, thanks! Link to comment Share on other sites More sharing options...
solder_guy Posted January 27, 2008 Author Share Posted January 27, 2008 Hopefully the harbor freight version won't catch on fire and burn the car down. Just put two in series! :jester: Rob Link to comment Share on other sites More sharing options...
MHKflyer52 Posted January 27, 2008 Share Posted January 27, 2008 Just put two in series! :jester: Rob Don't laugh Rob as I know of a BobCat that has one in plane sight and one hooked up in a hidden compartment to help prevent it from being stolen from the job site that it is left at when needed. Very cheap way of preventing the local yahoos from messing with the equipment. Link to comment Share on other sites More sharing options...
spotcheck Posted January 28, 2008 Share Posted January 28, 2008 When leaving the car parked for long periods, I had always thought that it was worthwhile to disconnect the battery. Does a cutoff switch perform the same function? Link to comment Share on other sites More sharing options...
MHKflyer52 Posted January 28, 2008 Share Posted January 28, 2008 Yes plus you can remove the key from the switch. Link to comment Share on other sites More sharing options...
slngsht Posted January 28, 2008 Share Posted January 28, 2008 When leaving the car parked for long periods, I had always thought that it was worthwhile to disconnect the battery. Does a cutoff switch perform the same function? Yes it does, BUT, you need to make sure it is wired properly. I don't have one on my car yet, so this is not from first hand experience. In addition to connection the main battery wire, you need to make sure you also kill the alternator signal line. Otherwise, in an emergency, somebody will reach over and turn your kill switch, but the car will continue to run without the battery if the alternator is not killed. Link to comment Share on other sites More sharing options...
MHKflyer52 Posted January 28, 2008 Share Posted January 28, 2008 Yes it does, BUT, you need to make sure it is wired properly. I don't have one on my car yet, so this is not from first hand experience. In addition to connection the main battery wire, you need to make sure you also kill the alternator signal line. Otherwise, in an emergency, somebody will reach over and turn your kill switch, but the car will continue to run without the battery if the alternator is not killed. Mazda your very correct and if your going to make it SCCA legal you will need one like this that is much more expensive. http://www.speedwaymotors.com/p/6967,71_Four-Post-Battery-Disconnect-Switch.html?itemNo=battery%20cutoff%20switch Link to comment Share on other sites More sharing options...
slngsht Posted January 28, 2008 Share Posted January 28, 2008 Mazda your very correct and if your going to make it SCCA legal you will need one like this that is much more expensive. http://www.speedwaymotors.com/p/6967,71_Four-Post-Battery-Disconnect-Switch.html?itemNo=battery%20cutoff%20switch You should be able to use the one Rob shows, with a relay to cut off the alternator, no? Link to comment Share on other sites More sharing options...
MHKflyer52 Posted January 28, 2008 Share Posted January 28, 2008 You should be able to use the one Rob shows, with a relay to cut off the alternator, no? I guess but I do know that most race orginizations require the switch to be a single unit to prevent the posability of the car running after the switch is thrown. Here is another site with the correct switch. http://www.discoveryparts.com/cgi-bin/store/commerce.cgi?cart_id=1201539834.589&product=battery&pid=449 Link to comment Share on other sites More sharing options...
Boxologist Posted January 28, 2008 Share Posted January 28, 2008 the 2nd switch is sounding like a good idea. but can the SCCA legal switch (alternator and battery) be installed in line with the battery switch. the dual function switch can kill everything when teh circuit is closed, but the simple switch is used for security purposes to open the circuit and is descretely placed? more switches with handle/keys that can be lost. like if u travelled 600 miles and went to an autoX in the dead of summer under murderous sun... RPW battery disconnect http://www.racerpartswholesale.com/product/1908/Battery_Disconnects caterham kit https://www.caterhamparts.co.uk/product_info.php?cPath=104&products_id=362 Link to comment Share on other sites More sharing options...
Kitcat Posted January 29, 2008 Share Posted January 29, 2008 Two pole switch from Harbor Freight: $2.99. SCCA 4 pole switch: $26.00 Official Caterham switch: $93.00 Hmmmm.... Link to comment Share on other sites More sharing options...
southwind25 Posted January 29, 2008 Share Posted January 29, 2008 All parts falling off this car are of the finest british workmanship. Link to comment Share on other sites More sharing options...
Keith Posted January 29, 2008 Share Posted January 29, 2008 I put those keys on my cars. Not so much for track work, but because it lets me cut out the battery when the car's parked for a long period - or when I'm working on it. Very nice. After having a cutoff switch fail on a car during a 25 hour race, I can't bring myself to use the cheap HF ones. Mine are made by Hella and come from Del City. Link to comment Share on other sites More sharing options...
drew... Posted January 29, 2008 Share Posted January 29, 2008 :7frog: anybody have a wiring diagram for a caterham showing wire connections and diode placement for the four pole switch?? Link to comment Share on other sites More sharing options...
pierats Posted February 2, 2008 Share Posted February 2, 2008 Drew: How do I fit a battery master switch Link to comment Share on other sites More sharing options...
JohnK Posted February 2, 2008 Share Posted February 2, 2008 This topic was on the USASe7ens list. It started it with a question about disconnecting the alternator along with the battery to save the alternator's diodes when such a switch was used. I've posted a synopsis of that thread at the end. With regard to the Harbour Freight switch, there was a 1967 Ferrari 412 P on display at the Cincinnati Art Museum last month and I noticed the characteristic handle of one of these switches poking out of the bodywork just behind the right door - on the exterior of the car for First Responders. That started me thinking that one of these switches would be a cheap insurance policy when connected in series with the battery ground. While, as Mazda pointed out, this may not prevent the engine from continuing to run sans battery, it can allow you to prevent the battery from dumping all its energy into your wiring in the event of a catastrophy. snip ----------- - I have the FlamingRiver switch. What lead me to buy it immediately is that it's a push-off rather than a paddle that needs to be turned in the correct direction- I figure if I'm ever in a situation where I have to shut the car off in a hurry, the last thing I want to do is have to think about which way to turn a lever. The FR switch works admirably in this regard - you wind it up to turn it on and it gives you a button nearly 2" in diameter that just needs a good slap to pop into the off position. It's mechanism is very positive. Workings. -A subtlety that needs to be appreciated when looking at a hook-up diagram for this switch is that the high amp terminals of the FR switch connect current which flows FROM the Battery to the system, but also FROM the Alternator to the Battery (when the alternator is supplying energy to the system and battery). The wire on the far side of the switch which feeds the System, is also a feed, back to the Battery. Now, the FR and Pegasus switches have three switches in a single package, all operated by the same lever / button. The first is the Battery to System switch which is Normally Open (i.e., when the switch is OFF, the battery is disconnected from the System. The second switch is also Normally Open, and the third is Normally Closed. All three change state in unison when the lever / button is toggled. To run the car you toggle the lever / button ON which closes the first and second switches and opens the third. The first switch supplies current from the battery to the system as a whole. The second switch can be used to feed power supplied via the ignition switch to the coil, isolating the engine run-control to the FR (and Ignition) switches. Use of the second switch in this way disconnects power to the coils when the lever / button is toggled off, ensuring that the engine stops. The third switch is wired by the owner to connect the system side of the first switch to one of the third switch terminals. the other third switch terminal is connected to ground through a low value resistor. When the lever / button is toggled OFF, this switch closes connecting anything supplying current on the System side (typically the alternator) to ground through a small resistance. Cherik's point about the system continuing to run even after the battery's been disconnected points out the importance of draining the output of the alternator while the alternator is still spinning and creating current (unless the ECU is smart enough to turn it off). What really muddied the waters for me is what FR ships. The 3 ohm resistor they supply is 1/8 watt (!!!) which would certainly blow out the first time the switch was turned off- and the documentation states that this resistor is used to protect the ECU. Their diagram shows the first of the three switches connected to the Starter. Somebody at FR needs help. -Unresolved - the stock setup on an S2000 has a 100 A fuse between the alternator output and the positive terminal of the battery. Knowing Honda's reputation for reliability, I doubt that the blowing of this fuse would also take out the alternator d Link to comment Share on other sites More sharing options...
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