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hello,
I hope this isn't a stupid question, so here it goes...
I'd like to run a battery cut off or disconnect and put it inside the car, that way I don't have to raise the hood each time I use it. The disconnect will be on the ground. My question is, does the the battery ground have to be connected to the engine block? Can I ground the battery to a bolt welded through the floor inside the car(used for another purpose)? If not there, where is a good place to ground other than the engine block. FYI the reason I ask is because I don't want to run 2, 4 gauge wires through the fire wall(1 from engine to the cut off and 2 from the cut off to the battery). It would be easier to run one from the neg battery post, to the disconnect, and from the disconnect to the grounding spot inside the car?
Any suggestions?
You are going about this completely wrong in my opinion. You can accomplish what you want with a continuous duty 3 terminal solenoid, such as the Cole Hersee 24106. You connect the positive battery terminal to one of the large terminals on the solenoid, and then connect the positive cable that presently goes to the starter, to the other large terminal of the solenoid. Then a 14 or 12 gauge wire, connected to the hot battery terminal of the solenoid, is brought into the cab of the car to a switch, and back to the small energizing terminal on the solenoid. When you flip the switch, you will energize the solenoid, and it will make the connection to the starter. If you presently have a positive wire that is going to anything else in the car, that will also need to be relocated onto the large terminal of the solenoid. Just keep in mind that if you turn off the switch prior to shutting off the engine, you will blow out the diodes in your alternator. This is the method that was used in ambulances for many years that ran dual batteries.
If you want, you can also use a Cole Hersee 24059 Insulated Continuous duty solenoid. With this switch, you can jumper from the positive battery terminal of the solenoid to the energize the small terminal of the solenoid, and then use a single wire from the other terminal to the switch, and a short wire from the switch to ground. This will reduce the wiring to one wire. Either way is correct and safe. My 1969 Cadillac ambulance uses two 24059 solenoids to connect two 12 volt batteries to the system. Generally, you only used one battery when running lights and siren on an emergency call, and if when you arrived at the hospital, and turned off the engine, and the car wouldn't start due to a low battery voltage, you could switch on the other battery, and be back in service. Once the car was running, you switched on the "dead" battery, and the alternator would charge it back up. If you would like pictures, I can provide them for you.
thanks for responding!!
will that method disconnect the battery completely, and that method seems to deal with the power or positive side. I thought the positive should stay connected.
I'm not to experienced, so I'm looking for a simple way to kill my battery with the switch inside the car, so if your method meets these points, please post pics!!
BTW i already purchased the 4 gauge wire(cut to fit) and the fittings
You always want to disconnect the positive terminal on a negative ground electrical system car. This is the GM factory approved method that was used for many years by the Professional Car builders, and it is the safest method that I know of for single battery applications. When the switch in the cab is in the off position, there will be no current flowing to anything inside the car (using the 4 wire solenoid), or under the hood. You will need a short battery to solenoid cable, and you can cut your existing cable end off, and install a terminal end on the cable. NAPA sells a terminal end that has a solder pellet in the bottom. You heat up the terminal end, and then insert the bared copper wire into the terminal. When it cools you now have a perfect connection. I use a large piece of shrink wrap slid down the wire and when the connection is cooled, I slide it up, and shrink it onto the end. Possibly you can return the cable you purchased, and get another cable that is better suited for your use. A 16" #4 battery cable is about $5.00 or $6.00 at Advance Auto.
I'm using a 1 wire alternator that connects to the battery hot side, does that go to the big terminal too? Also, the horn relay power wire, the power seat wire, and my amplifier all go to the big terminal??
I'm using a 1 wire alternator that connects to the battery hot side, does that go to the big terminal too? Also, the horn relay power wire, the power seat wire, and my amplifier all go to the big terminal??
The one wire alternator wire will go to the switched side of the solenoid, and when you switch on the solenoid, it will be energized to the alternator. I believe that the horn relay wire goes to the battery terminal on the starter, so if that is the case, then you won't need to be concerned about that. Same with the power seat wire. Your amplifier will need to also be connected to the system somewhere. What has me puzzled, is how is all this presently being handled? These items should be protected with either fuses or circuit breakers. If your power seat is factory installed, then I am quite certain that it comes off the starter and it is protected by a 30 or 40 amp circuit breaker behind the left kick pad. Basically, all that you are doing with the solenoid is putting it into the battery terminal wire, and everything else in your car should work as it normally does. If your car has been molested, and is full of wiring gremlins, then you are going to need to straighten that part of the project out yourself. Without my being able to put hands and eyes on it, I prefer not to be giving advise on how you should be wiring your car beyond your original question. You will understand more after I post the pictures tomorrow.
I would strongly recommend that any battery disconnect be on the NEGATIVE terminal of the battery, and as close to the battery as possible.
This is an ongoing argument on many automotive forums, in the same vein as ported vs. manifold vacuum for the distributor. The bottom line is that if the disconnect is on the negative side, shorting from EITHER battery terminal to ground will do nothing. If it is on the positive side, shorting from the positive battery terminal to ground will be exciting.
Yes, you MUST run the primary negative battery cable to the block. The starter is by far the highest current draw on the vehicle. Any additional resistance in the starter circuit and you'll start a thread about how your car is hard to start.
thanks Joe for answering. So how would you recommend putting a disconnect inside the cabin? Is running a 4 gauge wire into the car close to the firewall to far from the battery?
My idea was to attach the shut off on the center console (custom) at the forward most part close to the heater vent, but not right up on it(I hardly ever run my heater and there's a fiberglass divider between them). So I'd run a wire from the block to the cut off, and from the cut off the the negative battery terminal(2 wires through the firewall). What about this?
Id prefer to use what i have purchased already and its for the negative battery cable. My man Junkman has an idea for getting my cutoff inside the cabin, but I'd have to buy more stuff, and its on the positive side.
Last edited by westside807; June 29th, 2017 at 08:57 AM.
This is how General Motors installed them in the 1969 Cadillac Commercial Chassis in 1969. I believe that GM had a reason for doing it this way, and I trust their engineering. To this day, every dual battery ambulance and fire truck manufacturers switch the positive terminal using a few different type of commercially made switches. It is your car to do as you please, and to take whatever advise you want to use. Good luck with your project. Below are the pictures that I said I would post for you.
All I can say is that whenever I have to disconnect a battery, I ALWAYS remove the negative terminal first. If the wrench slips and hits ground, there are no sparks. Try that by taking off the positive terminal first. This is common sense.
thanks Joe for answering. So how would you recommend putting a disconnect inside the cabin? Is running a 4 gauge wire into the car close to the firewall to far from the battery?
My idea was to attach the shut off on the center console (custom) at the forward most part close to the heater vent, but not right up on it(I hardly ever run my heater and there's a fiberglass divider between them). So I'd run a wire from the block to the cut off, and from the cut off the the negative battery terminal(2 wires through the firewall). What about this?
Id prefer to use what i have purchased already and its for the negative battery cable. My man Junkman has an idea for getting my cutoff inside the cabin, but I'd have to buy more stuff, and its on the positive side.
I always prefer to put the cutoff as close to the battery as possible, since this minimizes the length of the pigtail still attached and also minimizes the length of the cables, reducing voltage drop.
What you need here is a magnetic latch relay. These require only momentary power to either open or close the relay. One such relay is the Intellitec Battery Relay. The primary power terminals are independent from the control terminals, so you can put it in either the positive or negative cables.
The two small terminals are simply connected to a DPDT momentary contact switch (like a power seat or power window switch). Momentarily apply power on one and ground on the other to latch the relay closed. Reverse to open the relay.
Yes, it is common sense to remove the negative terminal first every time and every service manual will also instruct you to do it that way, however, t we are discussing about switching the positive vs. negative, not using a wrench. If the "modification" is done properly, then there is a very limited possibility that the positive wire will ground out, and if it does, it will be a result of a poor installation or a MVA. If he wants to switch the negative terminal, he can still use the General Motors method, by using the 3 terminal solenoid, but this will still require him to purchase additional parts, which he has said that he would rather not do. I have no idea what type of switch that he intends to use with 4 gauge copper wire, but if it isn't rated for the amperage, he still runs risks.
Yes, it is common sense to remove the negative terminal first every time and every service manual will also instruct you to do it that way, however, t we are discussing about switching the positive vs. negative, not using a wrench.
The wrench analogy was only an example. My point is that by disconnecting as close as possible to the negative battery terminal, you are protecting as much of the wiring as possible.
Thanks guys. I appreciate your input. I'm planning on using a switch like the pic I've posted. This Will be hidden inside my console, or attached to my console
Last edited by westside807; June 29th, 2017 at 11:48 PM.
I have two old Oldsmobiles, one which uses a side-post battery and the other a top-post battery. I bought a cut-off switch for each type from Gama Electronics.
I actually bought mine through Amazon because I'm a Prime member and get free, two-day shipping. They're still sold by Gama, but through Amazon.
Both of these are placed on the negative terminal of the battery. Just unscrew the **** a few turns to disconnect, and tighten it back down again when you're ready to go. Very quick and convenient, but, yes, you do have to lift the hood. But they're a cheap, practical way to have a battery cut-off capability.
These were recommended in an article in JWO a few months back.
oldcutlass,
What I'm trying to do is to add an extra inconvenience for the would be thief, but I don't want to have to pop the hood each time I disconnect. And I have a slight battery drain I haven't found yet, the cut off will help with that, but that is not a major concern as I'll find that drain soon enough. The main thing is to add an extra step and time to the person who may try to steal the car, and I'd like for it to be inside the car. Yes I could put a switch on the ignition wire(still might) or a host of other items, but this is the route I chose.
I think my car is pretty cool, and I plan to take it on long road trips(taking my high school senior to visit colleges this summer). I haven't yet installed an alarm so installing cutoff switches(and locking doors) is my most economical way right now.
I haven't yet installed an alarm so installing cutoff switches(and locking doors) is my most economical way right now.
Car alarms are worthless. Has anyone here called the police when you heard a car alarm go off?
I'm a big fan of ignition kill switches. Simple to wire and just enough of a PITA for a potential thief that they will usually go on to another car rather than taking time to troubleshoot. If you have points, the cleverest thing to do is to wire a switched line from the NEGATIVE terminal on the coil to ground. With the switch open, the car runs normally. With the switch closed the points are grounded and the car will crank but not start. Even running a hot wire to the coil will not bypass this grounded coil. Most people will see the wire and assume it's a tach feed or something. Unfortunately, this won't work on an HEI, and I don't know what grounding the coil will do to an electronic conversion like Pertronix.
The other thing I like is a slow blow fuse in the power wire to the coil, with a bypass switch. Close the switch and the car runs normally. Open it, and the car will start then die when the slow blow fuse blows. Car will then crank but not start. Thief assumes it just runs like crap and moves on.
I have two old Oldsmobiles, one which uses a side-post battery and the other a top-post battery. I bought a cut-off switch for each type from Gama Electronics.
I actually bought mine through Amazon because I'm a Prime member and get free, two-day shipping. They're still sold by Gama, but through Amazon.
Both of these are placed on the negative terminal of the battery. Just unscrew the **** a few turns to disconnect, and tighten it back down again when you're ready to go. Very quick and convenient, but, yes, you do have to lift the hood. But they're a cheap, practical way to have a battery cut-off capability.
These were recommended in an article in JWO a few months back.
This is what I run on all my old cars. They are made in USA, they don't have the ugly green ****, and they fit on the neg terminal. I'm handicapped, I use crutches, I don't have any problems opening the hood and loosening the ****. My cars are always disconnected like this, I just leave the hood open 'til I'm ready to go out again. I don't really understand why anybody would want to disconnect power inside the car. Of course, my garages are alarmed.
Last edited by mrolds69; June 30th, 2017 at 07:32 AM.
mrolds69,
I want to disconnect inside the car for convenience and tact. When I'm out with the wife or on a business trip in my cutlass I prefer not to have to raise the hood when I get out and before I get in. Its not a problem for you, and that's cool. I've been popping the hood also but now I'd like to flip/turn a switch in the car.
Sure, I get it, different strokes. Some people pull the rotor, some the coil wire, bat disconnect, etc. Like Joe...I'm a big fan of kill switches, too. I don't use them now, but I used to in the past. The beauty of the kill switch is multiple...it's super cheap, super easy, you are not bringing power into the car, and as Joe says...it's like old school, most peeps will not notice it or think it's a tach wire. You can hide it in the ashtray, console glove box, AC duct...whatever. Truth is, I rarely leave my cars unattended for any length of time. And...I've got heavy collector insurance on them!
Sure, I get it, different strokes. Some people pull the rotor, some the coil wire, bat disconnect, etc. Like Joe...I'm a big fan of kill switches, too. I don't use them now, but I used to in the past. The beauty of the kill switch is multiple...it's super cheap, super easy, you are not bringing power into the car, and as Joe says...it's like old school, most peeps will not notice it or think it's a tach wire. You can hide it in the ashtray, console glove box, AC duct...whatever. Truth is, I rarely leave my cars unattended for any length of time. And...I've got heavy collector insurance on them!
Since this thread has somewhat morphed into an anti-theft device thread, I'll share my favorite. When my 67 Cutlass beater was stolen in Cambridge, MA during my college days, I was forced to drive my 68 442 to school. Since I pretty much had to park on a busy street in front of my dorm, I was naturally concerned about theft. I had installed a four spoke sport wheel in the car and determined that it was pretty easy to simply pop the horn button, remove the contact ring, and pull the six phillips screws to remove the steering wheel. I would take the wheel with me to my dorm room. With practice, I could remove or install the wheel in 90 seconds or so, and only beeped the horn when I snapped the button back on the horn ring.
One of the cleverest ignition kill switches I have heard of is modifying the cigarette lighter where there is a switch on the back that disconnects the ignition feed when the lighter is pushed in and then when it is pulled out slightly it connects and the car starts. This could also be used to ground the coil. A thief would never figure this one out. The biggest problem is most of us use the lighter as a power port these days.
I understand wanting an in-cab method of disconnecting power, but I would not bring heavy 4 gauge battery cables through the firewall into the passengers compartment. Using one of the switched relays that Joe and Junkman posted allows you to have control from inside the car with a simple toggle switch and some light gauge wire running through the firewall. It accomplishes what you want while keeping the wiring simple.
I really appreciate the information guys, I have a few decisions to make, now if I can figure out how to get 20 or so miles to the gallon with the account running going about 75 mph with a .030 bored 350 with headers and stock cam, lol thanks guys have a great weekend
Most often nowadays thieves are not driving these cars of when stealing them. They drag them up on to a flat bed and off it goes. I personally make sure my car insurance is adequate and carry on.
I have two old Oldsmobiles, one which uses a side-post battery and the other a top-post battery. I bought a cut-off switch for each type from Gama Electronics.
I have the OEM spring clamp battery cables on my Toronado. Will they get a good enough grip on this to make it work?
I don't know know what these clamps look like. Any chance you could show a photo?
Also, since I posted this three years ago, I decided I didn't like the side-post switch I was using on my '78 Toro. I'd unscrew it thinking I had disconnected the battery only to find later that I hadn't unscrewed it far enough, and the battery was never disconnected. I ended up having to open the car's door each time to make sure the dome light didn't turn on.
So I got rid of that and bought one of these. Works much better because I KNOW, without a doubt, whether or not the battery is connected.
I have the OEM spring clamp battery cables on my Toronado. Will they get a good enough grip on this to make it work?
Originally Posted by joe_padavano
Thanks for the image.
In watching the video on how to install this at the Gama website, I think the spring clip should work just fine. If the spring is strong enough to maintain a connection to a post on the battery, it should be strong enough to attach to this switch.
Your spring clamp cable would be installed where the black cable is in this photo. As I say, take a minute and watch the video on how this is installed at the Gama website. It should work fine.
Just my two cents, those **** disconnect switches and knife switches are super sketchy. The **** ones can't handle much current, and the knife ones are easy to have terrible connections.
I use one of the **** ones to disconnect my garage battery from my winch because it's quick and easy, but wouldn't put one in a car.
Just about anything is fine if you're only breaking the power line from the starter to the rest of the car. You need something pretty beefy if you're going to break the main ground or the power line to the starter, since starters will pull >200amps. Sure, it's hopefully only for a few seconds, but this is the kind of stuff that starts fires.
I dug around on disconnects a few years ago, and the only one I actually trusted the ratings on is the Flaming River Big Switch. It's easy to take apart and verify the construction. Most of the switches use really small internals, so it's easy for them to melt, weld, spark, etc. I think some of the marine stuff actually meets their advertised ratings, too. But this is an area where the advertising doesn't necessarily reflect reality.
As for the spring clamp, don't be surprised if the post on that disconnect is too small. You can just wrap some bare strands of copper wire around it to build it up a touch.
Just my two cents, those **** disconnect switches and knife switches are super sketchy. The **** ones can't handle much current, and the knife ones are easy to have terrible connections.
I have had the knife-switch cutoff I showed above installed on my car for over two years now without a problem. It may be easy to have terrible connections, but it's also easy to keep it in good working order, and it's also easy to have terrible connections with just the battery cable alone connected to the battery if it's not properly tightened or there is corrosion.
In my opinion, the best/safest way to kill electrical power is to either use a latching relay, or a ford starter solenoid to isolate the starter cable unless the engine is cranking.
[img]blob:https://classicoldsmobile.com/3f9748c2-e9ef-4652-88b4-c9bcece50451[/img]Using this method in the diagram means the main disconnect switch doesn’t need to be nearly as big, since the most current it needs to handle is basically whatever the alternator is capable of. The starter cable isnt energized unless The engine is cranking ( and the engine can’t crank unless there is power supplied from kill switch to the main distribution point). The only downside is the heavy wire from the alternator charge post needs to go to the main battery positive post on the starter solenoid. If the battery is in the trunk, that means another heavy cable ran to the rear of the car.
I sent an email to Gama, hoping their switch was heavier duty than most, but so far have not gotten a response. I've had the ones with the green ***** on other cars over the years, but they were on cars that don't have a high-compression 455 and need a battery with a lot of cranking amps. The Toronado battery burned the brass paint off the switch I had and partially melted the battery cable to the switch. So, yeah, Oddball is right in that they're a bit sketchy for some applications. The reason I put it on to begin with was after reading Ralph Braun's article in JWO about fires in 1969 Toronados. But my car is over 50 years old and hasn't had a fire yet, so maybe I'm over-thinking it. I did use my 3d printer to make a fire extinguisher mount, though.
June 28th, 2017, 09:00 PM
