I'm shocked (pun intended) that now there's yet another use for a relay. So the simple badass "jerk off" switch we all know and love is a no-no? Yeah, all the drag racers I know call it a jerk off switch cuz of the outside pull handle. But seriously, a relay? Again? Really? Think it through for a moment. Those 200+ amp switches all have a surge rating, right? So unless you're operating some monolythic equipment when will you ever need HUNDREDS of amps in our simple hot rods? Show of hands, what's the 1st hit amp draw when you start your car, and for how long? Biggest hottest amp draw is trying to get shit to work with low battery voltage like trying to start with jumper cables and not enough boost. However, I guess I'll relay this new info to all the folks that just have the big switch, then tell them to relay their friends to come and get the newly relayed info about putting a relay in their shut off switch circuits. I have a feeling some will call ME the jerk off...switch
If you are just wanting a theft deterrent, why not use the fuel or ignition system to disable the vehicle. I hesitate to add any component to the cranking system because of the greater load the system needs to be able to carry. Every connection provides a possible problem, and I like the starting system to have as few connections as possible. A simple toggle switch (possibly with a relay) that disconnects the ignition or electric fuel pump is easier and cheaper. Much easier to hide a smaller switch. Also, those that have components like radios that need continous power don't want to completely disconnect their battery. You could also wire an alarm that sounds when the engine is cranked while the ignition or fuel pump are disabled. Someone trying to start a car at night in a motel parking lot would immediately vacate if they cranked the dead engine and an alarm sounded. Having been burglarized in the past, I can tell you that noise is THE best deterrent.
Yup, just a hidden two-way switch on the crank lead can do that. In one position, it connects to the starter solenoid and the car starts as normal. In the other, it connects to an alarm siren. I have an NC solid-state relay, and an blinking LED on the dash. When the key is off, it blinks. I have more than that but I'm not telling.
I learned about this product from a quality car builder (won the AMBR for the first time 50 years ago) Lonnie Gilbertson. We have installed them on no less than 100 cars, they work great. The OP wanted only to kill the power while stored, because of old wiring, not as a theft deterrent.
I usually agree, and many times been frustrated by the extra opinions, although as I read this thread 2&1/2 years later I am finding more information on this one thread, about the topic that I searched, than what I have found on all the other threads combined, so sometimes the extra opinions are welcome and in this instance, really helpful..………..…. Thanks to all those that posted !
This is essentially the Cole Hersee 22400 that Marty mentioned. It’s also available From NAPA as either a TWD # 24200BX or an Echlin ST-90. If you’ve ever looked at a Painless Wiring remote battery disconnect this looks to be what is included in their kit
However if people would have answered the OP's question instead of the first several responses saying "no don't do it", maybe someone would have known there's an easy solution in a kit from Painless (referred to by @uncle buck in the post before mine) that has been around since long before the original question. https://www.summitracing.com/parts/...4DBdKftC2XGHF5IpgoxLm2DCb0NtaRDQaAphvEALw_wcB https://www.painlessperformance.com/wc/30204 Not only does it use a similar solenoid to those shown in the thread, but it shows that yes it can be done and there's no issue with it.
If you use a solenoid you simply run a small fused wire to the control switch off the positive post direct off the battery. Same as you would to save memory for the radio if you install a manual kill switch. I have my cars with manual kill switches, but alarms and radios get a 2 a. fused constant hot to work.
If you use a Cole Hersee 24200, there is no power needed at the switch, the switch simply makes the ground to switch the solenoid on/off. A small jumper wire goes from the large, battery terminal to the smaller terminal to power the solenoid, that's it.
The Jalopy Journal
