Off/On Switch between Battery and Starter

My sole reason for always putting the switch in the ground side is to avoid problems in the cable between the switch and the battery connection,and in the switch itself.I fixed two A's that had problems with firewall mounted switches.One had the cable pull out of the lug,it bounced around on the steering box and the starter,It made a bunch of arc welded spots.Another had the cable too tight and chafed through on the edge of the firewall,that one blew up the battery.No matter what side it goes on it will work fine,I just want to eliminate that extra trouble spot.If the cable pulls out,the switch melts,or something chafes the cable or grounds the switch it is no big deal.I don't know where trucks would have had them,I never saw any that had factory switches.The outfit I worked for in the 80's had mostly Cat equipment with switches on the ground sides.I put switches in all the Macks he had,all in the ground side.My 1963 Lorraine loader, Allis-Chalmers dozer,and a Cat D-6 all have them in the ground side from the factory.I have an 02 Bobcat excavator,Kubota powered,that has the switch in the hot side.But,the switch is 10 inches from the battery.I just can't see any sound reason to require them to be on the hot side,unless it is for uniformity.
 
BILL WILLIAMSON said:
So if they're SO important, why didn't pre-solid state cars have them? If your battery to starter cable is routed properly & secured where necessary, & you have a main feed fuse or a circuit breaker, what's the chance of a disastrous short? I feel that a cut off switch is just something else to possibly fail. Bill W.
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Ever had a starter switch fail?
 
I use the So-Cal Speed Shop off/on switch on the ground side of my cars. Costs about $30 and has a metal key. Had a plastic switch malfunction as well as the green battery connectors fail at the most inoppurtune time.

Brent...i consider the battery switch a low tech anti theft device.
 
denis4x4 said:
i consider the battery switch a low tech anti theft device.
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Not too many theives around here who could work out how to start it, let alone drive the thing! :D

We have it there purely as a anti drain device and a safety switch - less likely to have an electrical fire while parked in the Barn, and when my kids climb in a play, the starter button doesn't make the car drive forwards if left in gear :eek:.
 
BRENT in 10-uh-C said:
I doubt it ....but while some here have argued saying it should disconnect the battery ground, --NHRA, NASCAR, and a couple of dirt track sanctioning bodies all specially state it is to be on the positive battery cable.

A month or so ago I was at a used truck dealership and specifically looked at this on Kenworth, Peterbilt, and one other mfg (I forgot what I looked at) of heavy-duty trucks, and for the ones that were equipped with a disconnect switch, they all had a switch disconnecting the cable that feeds the electrical circuit and not disconnecting the ground. One day when I have the opportunity I want to stop at a heavy equipment dealer and look how they are wired on a dozer or loader. So I guess this still begs the question why if all these others are saying the power feed cable, then why are some suggesting to disconnect the ground?
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The big forklifts like Hyster have them in the pos side. (neg ground systems)
 
Yep! 6V pos ground, cut out in floorboard between seat and ******! Must be easy and quickly accessable. I use it every time I leave the car. I also shut off the gas under the tank.

The only fire I've witnessed was caused by the starter foot button coming loose and shorting to the post on the starter. No cutout almost cost them the car. All wiring was in top shape. Just forgot the jam nut.
 
BILL WILLIAMSON said:
So if they're SO important, why didn't pre-solid state cars have them? If your battery to starter cable is routed properly & secured where necessary, & you have a main feed fuse or a circuit breaker, what's the chance of a disastrous short? I feel that a cut off switch is just something else to possibly fail. Bill W.
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That's a lot of if's.
There is no point in having insurance if you don't wreck your car.


When your battery to starter cable is routed and secured properly and the smoke is coming out from the gauge panel in front of the gas tank while you're cruising down the road at 50 mph it would be nice to reach down and shut off the battery switch and maybe prevent a fire.
Bill
 
BRENT in 10-uh-C said:
My thoughts are it seems like we have beat this proverbial horse absolutely to death just like the discussions of what proper oil to use, the actual viscosity of 600wt., whether vapor lock exists in a gravity fed fuel system, ....and which side of the battery should be interrupted with a disconnect.

The thing I have always tried to understand is exactly what are you trying to accomplish with this switch. As a theft deterrent or to eliminate a battery drain, the type Paul is suggesting is more than adequate. If a starter switch sticks, then the type Mitch suggests is fine. In the event of an accident, just exactly what are we trying to accomplish? For those of you who have tried this, with the engine running lift either the positive or negative battery cable from the battery post and you will notice the engine will still be running if the charging circuit is functioning properly. Therefore it doesn't do anything to switch the cut-off switch off in an effort to kill the engine during an emergency. An additional thought is if something metallic gets against one or more battery posts as result of an accident (i.e.: brake rod, frame rail, battery hold-down, etc.) being able to disconnect the ground via a switch will not be effective if there is an object laying against the ground post of the battery. Interrupting the starter cable will not do anything to protect a short between the battery post and the switch should the cable get damaged however it will interrupt a multitude of possible shorts on through the wiring harness unlike disconnecting the ground circuit will.

A great example of this would be a brake light switch could become shorted while driving. If the ground circuit were interrupted with a switch, as long as the generator/alternator were still providing current, the gen/alt case is grounded through the same metal as what the brake light switch is grounded thru!! Not much benefit of interrupting that circuit in my view!!



As far as which switch is the best, I was thinking Cole Hersee was the original manufacturer of these switches, ... and now there are Chinese 'knock-offs' so plentiful that I doubt someone could tell the difference between them. Again, define the reason you want one but I think most folks have a false sense of security the way they have them wired.

.
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Brent You can stop the engine pretty easy but how are you going to stop the battery from feeding the short without a switch?
In the event of an accident the engine is probably off but the battery is still in the circuit without a cutoff switch
And what if that object is laying against the hot post? You could shut the switch off and break the circuit.
Caterpillar puts them in the ground cable!
I guess we beat this horse to death because some people still don't get it
Bill!
 
Question ?:

In looking at the "Yeahs" & "Nays", if somebody already neatly installed a heavy duty cut-off keyed switch in his Model A, & he later decides to remove it, & to not have any type of cut-off switch, might he be excommunitcated for changing his mind?

(Maybe more to follow next week.)
 
bbrocksr said:
Brent You can stop the engine pretty easy but how are you going to stop the battery from feeding the short without a switch?
In the event of an accident the engine is probably off but the battery is still in the circuit without a cutoff switch
And what if that object is laying against the hot post? You could shut the switch off and break the circuit.
Caterpillar puts them in the ground cable!
I guess we beat this horse to death because some people still don't get it
Bill!
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Ok I can play your game too, ....what if an object is laying against the ground post?? :rolleyes:
 
BRENT in 10-uh-C said:
Ok I can play your game too, ....what if an object is laying against the ground post?? :rolleyes:
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Well Brent, that's exactly one of the points. If the object is laying against the ground post it isn't a problem unless inthe not very probable event that it also contacts the hot terminal. However at the hot terminal, every single piece of metal around is connected to ground, hence a short is highly probable, and the only thing that will help you then is a cutoff switch on the ground connection.
 
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Well, the Dog:cool: just tole me, "You'd better put one of them cut out gizmos, cuz iffin' you burn up stuff:eek: & confess to them guys, they'll jist LAFF & say, 'WE TOLE YOU SO, DUFUS'":D Bill W.
 
denis4x4 said:
Had a plastic switch malfunction as well as the green battery connectors fail at the most inoppurtune time..
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The Green knob ones do require an annual cleaning to keep them on par, but then again, so does the battery is it connected too...I do them both each spring.
 
When I bought my Model A I put a shut off switch in the hot battery cable between the battery and starter in case of a power draw when not in use. I also put a fuse in the generator wire as I own several Reo cars and they are fused between generator feed and power block. I know I sleep better at night knowing I disconnected the power cable. Lifting the hood is easer than removing the seat to disconnect the battery cable. And hopefully if I have a short while driving car the fuse will blow.
 
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