POS or NEG Battery Disconnect switch

Listen, if the battery ground is switched off, the entire car is no longer a ground waiting to short anything. Aside from that, without the ground, nothing is 'powered up' waiting to short. There is no electron flow without the ground, and as I said, if the ground circuit is interrupted between the battery and frame, you can 'short' every 'hot' wire on the car directly to the frame and nothing will happen.

Sent from my DROID device using the TJJ mobile app

 

Everything you said is true---- and the same is true if the switch is on the positive terminal.

 

Indeed, that's the point some of us are trying to make, there is no functional difference.

Sent from my DROID device using the TJJ mobile app

 

NHRA regulates that the positive power be disconnectable, that's good enough for me.

BUT, here's my thinking: in the instance of an attempted theft, if the thief has no access to the "power", then they have no ability to bump the starter. If they DO have access to "power" (positive) then they can use anything as ground. Cutting the ground does not effectively remove access to power, while cutting the positive does. My battery is hidden under the chassis and there is no way to get to it unless you jack the vehicle up...period. Mine was a decision based on the desire to not only save the battery when stored, but create an effective theft deterrent as well.

 

I use the negative side,,I don't drag race so no need to adhere to NHRA rules. HRP

 

If the ground is disconnected at the battery under the car, where are the thieves going to access ground at? The rest of the car is no longer an accessible ground.

Sent from my DROID device using the TJJ mobile app

 

I have the battery grounding to the block and to the frame. In my case, I'd need two disconnects. Mine was situational, and doesn't apply to everyone.

 

I had one of the ones where you take out the red knob so nobody could switch it back on and steal my car.

I hooked it to the cable that was closest to where I wanted to mount the switch. I think it was the negative.

 

both work, but if used in the neg side and you flip the power off while car is running. as in a emergency. it will shut off , but the by product is that some electonics will hunt for ground and short themself out. have seen all ecm's shorted in a transit bus which the neg side switch was throw to try and shut down a runaway diesel.

 

I voted positive but it really does not matter. I am going pos. because most sanctioning race bodies require pos switch. on my last car which was a cruiser I had a Neg switch. In the maritime industry pos switch of battery circuit is required by ABYC and also milspec on military small boats. either way opens the path of flow allowing no power.

 

This is a situation where your disconnect was not a disconnect at all.

Sent from my DROID device using the TJJ mobile app

 

i use the neg. with a kill switch for the pos to the coil and fuel pump, after reading all of this i may also inculde and shut off on the pos side if the battery as well..

 

LOL, well...my positive disconnect does the job. I used one of those big Cole-Hersee disconnects and there's no juice once the lever is turned.

 

Sorry, but the statement that you can get ground "anywhere" is not accurate. It's not magic with "power" floating around looking for a place to land. A circuit is a circuit and you have to have a circuit for electricity to flow. If you interrupt the circuit all systems are disabled, and it doesn't matter where the interruption occurs. It can be broken on the left side or the right side, the + side or the - side. It just doesn't matter. The "+" side of a battery isn't like a garden hose spewing out electricity (power).

Think of the battery as a start/finish line at a Nascar race. One side is + and the other is -. Now to stop the race you have to open the pavement. Do you dig open the pavement before or after the start/finish line? Does it matter whether the cars are driving clockwise or counterclockwise?

 

It isn't??????????? There goes the "It's just like water" anology. Bob

 

Ron Francis---The wiring guy---says "Always put the battery disconnect on the POSITIVE wire. If you have a failure in a ground, the electronics might pick up that ground and damage some equipment. Master disconnects were fine in the negative cable, until electronics came along. Especially ones that remain powered, even when the key is off." In my case the only low voltage piece is my radio memory and I run a separate --fused --wire to that. BILL RINALDI

 

Well, I stupidly didn't clarify that the decision was based on MY SPECIFIC circumstance in my first post. I did in a later post, but apparently that's not being read as much as the first post. My battery is ground to BOTH the frame and the engine block, so I disconnected the positive so that I needed only ONE disconnect.

I should have said, "On MY truck, you would be able to find a ground anywhere"...

I'm sure 10 more guys will comment on my first post... oh well.

 

Hey, Buzznut, I hear ya. In your circumstance, the positive disconnect is the easier choice. In most circumstances it makes no difference.

Sent from my DROID device using the TJJ mobile app

 

It's still relevant, but it's the negative side that's spewing electrons, or at least trying to.

 

Bill, I'd like to hear more about this.

Sent from my DROID device using the TJJ mobile app

 

Bob, don't forget the ampy guys, they won't work unless they have a way home. http://www.jalopyjournal.com/forum/showthread.php?t=782663

 

Ted, there are no AMPS in Canada, and whatever that stuff is inside the wires flows both ways. Bob ..................I really don't understand Hocky either.

 

i thought it was spelled camada.

 

Sounds like a good idea . never thought of that.

 

Well the instructions that came with my switch said positive side so that's what I did, works good, lasts a long time.

 

It doesn't matter which cable you place it in, when you switch it 'off' one side of the switch will be positive and the other negative...or will one side be negative and the other side positive

I just know that if they were both the same polarity they would repell one and another and you could never close the switch again

 

Ok so disconnect the grounded side of your battery, turn on your ignition switch just to be sure it's powered up, take your coil wire off the distributor and hold it on your tongue.

If you have a positive ground vehicle, you switch the negative side. In other words, you always put the switch in the powered, not the grounding wire. It's not that either side won't work, it's the potential side effects that are the issue.

 

I would gladly disconnect the battery ground, place the coil wire on my tongue, and place my sweaty nuts on the frame rail and turn the key. Nothing can or will happen. There are no potential side effects that could occur on one side and not the other. It is a loop, a closed circuit, any break in it will stop the whole process.

I hope I don't have to go out to the garage and video tape myself doing the above just to prove it.

No one wants to see my sweaty nuts on video.



Sent from my DROID device using the TJJ mobile app

 

now i am going to have nightmares!

 

Good grief, can't you ever ask an easy question?