JohnCh Posted October 11, 2007 Share Posted October 11, 2007 Does anyone have any experience with this remote kill switch from Painless Wiring Products? I like the idea that I can have an unobtrusive switch in the cockpit to turn off the electrical system, so this seems to fit the bill. Thanks, John Link to comment Share on other sites More sharing options...
bsimon Posted October 11, 2007 Share Posted October 11, 2007 John, It looks as thought the relay does not have contacts to disconnect the alternator. This setup would work OK as a battery disconnect, but not as a kill switch since the alternator will still power the ignition after the battery is disconnected. You could add an additional smaller relay for the alternator. Link to comment Share on other sites More sharing options...
slomove Posted October 11, 2007 Share Posted October 11, 2007 Yes, I have this for a year or two now. It works perfectly and is IMO much safer in a crash than a manual battery switch with long "hot" leads. Bob is right that you need to turn off ignition separately but fortunately the one I have comes with a professional "big red emergency stop" button that has 2 sets of contacts, i.e. one to turn off the battery solenoid and the other on to turn off the engine. This button is not exactly "unobtrusive" but that is the whole idea. I still have the old ignition switch but don't use it anymore. If you really need an unobtrusive switch you can replace the one in the Painless picture with a DPST or DPDT from Radioshack and wire as shown below. Since the solenoid does not have the load dump resistor that many manual battery switches have (to avoid a voltage transient in the alternator when the battery is cut off) I added a heavy duty diode across the solenoid contacts that dumps any voltage spike into the battery (the aluminum tube under the solenoid in the picture). One slight disadvantage.....If you have the engine stopped and forget to turn off the solenoid the power for the solenoid itself will drain the battery overnight. That happened to me once when experimenting, but never in normal operation because I always use the big red button to turn off the engine. http://www.usa7s.com/aspnetforum/upload/1926295822_RedButtonDash.jpg http://www.usa7s.com/aspnetforum/upload/1035538871_CutoffSolenoid.jpg http://www.usa7s.com/aspnetforum/upload/193459899_SOLENOID.jpg (you may need to click on the picture to see all the lines....) Gert Link to comment Share on other sites More sharing options...
JohnCh Posted October 12, 2007 Author Share Posted October 12, 2007 Bob/Gert, Thanks for the feedback. Although a kill switch is a nice feature, I am really just looking for a remote battery disconnect. My battery is not easily accessible and I did have a small under bonnet fire a couple of years ago when the throttle cable broke, landed on the 12V+ connection to the alternator while touching the air filter. In case anyone is wondering, yes, a red hot cable will ignite an oil impregnated air filter. Quickly. I would really like to have a battery disconnect switch in the cockpit in case I have a similar problem in the future. One slight disadvantage.....If you have the engine stopped and forget to turn off the solenoid the power for the solenoid itself will drain the battery overnight. That happened to me once when experimenting, but never in normal operation because I always use the big red button to turn off the engine. I hadn’t considered the fact that the solenoid draws power whenever the switch is flicked to the on position. That will be a learning curve… Thanks, John Link to comment Share on other sites More sharing options...
slomove Posted October 12, 2007 Share Posted October 12, 2007 John, if just for the stated purpose, Painless offers a solenoid version with toggle function, i.e. one trigger button push it is on then another push and it is off again. That would do what you want and it does not need any power. But it would not be acceptable as a cutoff switch for safety purposes. Gert Link to comment Share on other sites More sharing options...
solder_guy Posted October 13, 2007 Share Posted October 13, 2007 (you may need to click on the picture to see all the lines....) I'm still having trouble seeing all the lines ... Rob Link to comment Share on other sites More sharing options...
slomove Posted October 13, 2007 Share Posted October 13, 2007 I'm still having trouble seeing all the lines ... Rob I think that happens when this site scales it down to 640 pixel. In my Firefox browser I can double click to open a separate window for the image and then click into that again to zoom to full size. Not sure about Explorer..... Gert Link to comment Share on other sites More sharing options...
soareyes Posted October 13, 2007 Share Posted October 13, 2007 Gert, I think this is the Painless unit you mentioned: http://www.painlessperformance.com/webcatalog/plarge/30206.jpg "Our Remote Master Disconnect with Mechanical Latching Solenoid is ideal for everyday vehicle applications and is a simple and effective anti-theft deterrent. It uses a 100 AMP continuous duty solenoid which is activated by an easy to hide momentary push button. No risk of accidentally draining your battery with this latching solenoid. Kit comes complete with one solenoid, one switch, mounting hardware, wire and connectors." I have been meaning to install a battery cutoff, and like John, I don't need it to be a kill switch, just a disconnect. Wouldn't this type of be just as effective as the Painless unit, but simpler and cheaper?: http://www.pegasusautoracing.com/Images/L/4431.JPG I was thinking of installing it through the scuttle wall so I can disconnect from inside the cockpit. Thanks for any advice! Link to comment Share on other sites More sharing options...
slomove Posted October 13, 2007 Share Posted October 13, 2007 Gert, I think this is the Painless unit you mentioned: yes that is the one I had seen before I have been meaning to install a battery cutoff, and like John, I don't need it to be a kill switch, just a disconnect. Wouldn't this type of be just as effective as the Painless unit, but simpler and cheaper?: Surely simpler and cheaper. But I think John wanted to have an inconspicuous switch and I wanted to have something that can disconnect the battery safely in a crash, e.g. on track. The problem I am seeing with the manual switches is that you need to route the "hot" 12V lead from the battery to wherever the switch is, possibly through the tranny tunnel into the dash or through a bulkhead grommet in the firewall. In my view that defeats the purpose because that hot lead can short out just as well and cause trouble. The solenoid can be installed right next to the battery with minimal wire run ( Gert Link to comment Share on other sites More sharing options...
Alaskossie Posted October 19, 2007 Share Posted October 19, 2007 With the "simple" battery cutoff, can't you just run the ground to it, rather than the hot lead? I need to know, because I'm jst about ready to install a "simple" battery cutoff switch under the bonnet, as a theft deterrent and easy battery disconnect (though not an in-cockpit emergency shutoff, admittedly). Tom Meacham Alaskossie Link to comment Share on other sites More sharing options...
solder_guy Posted October 19, 2007 Share Posted October 19, 2007 With the "simple" battery cutoff, can't you just run the ground to it, rather than the hot lead? Yes you could .. and I thought about that .. but the instructions with my batt cutoff specified hot lead. (I don't know why.) Rob Link to comment Share on other sites More sharing options...
slomove Posted October 20, 2007 Share Posted October 20, 2007 Yes you could .. and I thought about that .. but the instructions with my batt cutoff specified hot lead. (I don't know why.) Rob Yes I agree that could be done as long as you maintain low ground impedance and consider the (theoretical?) problem of voltage transients destroying the alternator when disconnecting. But at the end it comes down to disconnect the battery as closely as possible to the battery post (either positive or negative) plus shut down the engine/alternator to reduce the likelihood of a fiery short when the car is being mangled. Gert Link to comment Share on other sites More sharing options...
Sean Posted October 20, 2007 Share Posted October 20, 2007 Yes I agree that could be done as long as you maintain low ground impedance and consider the (theoretical?) problem of voltage transients destroying the alternator when disconnecting. But at the end it comes down to disconnect the battery as closely as possible to the battery post (either positive or negative) plus shut down the engine/alternator to reduce the likelihood of a fiery short IF the car is being mangled. Gert Corrected... I hope! Link to comment Share on other sites More sharing options...
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