Re: Cut off switch for 6v positive ground?
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IMO, the green switch is not really suitable for a 6v system. They are more for the 12v cars because the amperage rating on many of them is a bit low for the large 6v starter motor current. If you do go that route be sure and get a quality switch. Most of us use a Cole-Hersee switch or equivalent which is capable of carrying around 175 amps or more continuous instead of the 125 or less the green switches are typically rated for.
To get the best protection many of us also feel the cutoff should be in the ground wire. That way you can flip the switch disconnecting ground to the frame and not have to be as careful when using or dropping a wrench around the "hot" battery terminal to avoid accidentally touching the hold down or any other metal. Mounting the Cole-Hersee type is a bit more involved because unless you find a hole or mount it in the firewall to operate from inside it usually needs some kind of bracket. I mounted both of mine to operate from inside and placed the knobs at discreet locations under the dash edge. The 56 has an extended rotary knob and I modified the 47 switch to utilize a custom push pull cable.
Posted on: 2016/10/15 21:22
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Howard
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Re: Cut off switch for 6v positive ground?
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Just can't stay away
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Thank you.
I had read many of blogs and there are many different thoughts but, mostly on the 12 volt systems. The racing switch I purchased is rated for 300 amps but has 5/16" "brass posts" will the brass be a problem? I did purchase enough black cable to run it inside the car and back to the battery as my first thought of doing it although I can change that around.
Posted on: 2016/10/15 22:05
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The best are yet to roll
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Re: Cut off switch for 6v positive ground?
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Forum Ambassador
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Is the 300 amps surge or continuous? With 5/16 posts I would guess surge but it should be OK unless there is a something that pulls a huge current at some point. The continuous rating is the one to favor in case the starter motor cranks for an extended time. If the starter is marginal, it can pull 200 amps or more when trying to start a hot engine.
Brass is an excellent conductor so don't worry about that aspect. It tarnishes rather than rusts and is a bit weaker than steel. The tarnish isn't a big deal because as long as the connections are tight it takes a long time to develop enough to interfere. Just be careful not to go overboard when tightening the nuts. With 1/0 if you are going to mount the switch to the firewall, I would try to keep the additional length as short as possible. When you connect the switched side of ground back to the engine try to do it in the rear somewhere and not the original location under the generator.
Posted on: 2016/10/15 22:35
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Howard
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Re: Cut off switch for 6v positive ground?
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Just can't stay away
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I actually bought it at the beginning of this year, after googling it I found it is a 12 volt High capacity 300amp.
I just may go ahead and pick up what you had referred to me. Is this in that direction? https://www.amazon.com/Cole-Hersee-2484-Disconnect-Contacts/dp/B001FQMZS8 Yes if I went with a inside dash mount it would have to be trans bolt mounted in that area. I'm not too thrilled on the distance of cable but if I did that, I would change to 3/0 or 4/0 Red positive cable. Would the black Negitive cable have to match the 3/0 or 4/0 of a red Positive if I changed or can I keep the black Negitive cable at the 1/0?
Posted on: 2016/10/15 23:19
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The best are yet to roll
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Re: Cut off switch for 6v positive ground?
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Home away from home
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I started out with the green knob switch which failed/then to a knife type switch which also failed in that it developed a high resistance. I now just take the cable off the battery-ever so often need to use a file on battery and connector.
Posted on: 2016/10/16 9:10
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Re: Cut off switch for 6v positive ground?
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Home away from home
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I have bought heavy duty quick disconnect battery terminals from NAPA for my 6- and 12-volt cars. This is a heavy duty terminal, not the light duty that is typical of the "Green Knob" types. One part of the terminal clamps onto a battery post and the other clamps on the cable. I have had no problems using these terminals.
I install the terminals on the ground side. I use the terminals for safety not security as they not hidden like a switch used for security. Also, all my batteries are easily accessible and not under the seat like the pre-war cars. I always disconnect the batteries when the cars are parked to avoid electrical fires. (o[]o)
Posted on: 2016/10/16 11:32
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Re: Cut off switch for 6v positive ground?
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Forum Ambassador
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I don't think there is a need for the 3 or 4/0 wire because that will be hard to work with and probably overkill for that distance. If I were doing it, would have chosen 2/0 but since you have the smaller engine and starter on your car the 1/0 should be sufficient unless the length is going to be over 6'. If it is, I would go up one size. The negative cable to the starter is a fairly short length so should be OK at 1/0.
Cole-Hersee has several variations of that particular switch. Amazon has most of them. The main difference seems to be whether it has a UL label or uses silver or copper contacts. I believe the copper contacts are rated at slightly less capacity so I used the 2484A with silver contacts and no label on one car. A Summit equivalent is on the other.https://www.summitracing.com/parts/sum-g1437/overview/ Both of them are rated at 175A continuous and 1000A surge. I customized the operation of both switches to my wants. The 56 switch was mounted on the firewall and an extension shaft and bracket was made to bring the knob to the underdash edge area. Used a different style knob to blend in better. The 47 has the switch mounted under the battery tray. I modified its lever to accept a push pull cable and brought that cable and knob to a bracket under the rear of dash edge.
Posted on: 2016/10/16 11:34
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Howard
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Re: Cut off switch for 6v positive ground?
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Just can't stay away
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Thank you great help with the model number as I ran across the different extension numbers after the main component number.
I will order the best suited for my needs after the great advice. I already spent my day making my cables for a incompartment on the Positive ground cable near the battery box eliminating any long distance in cables. Switches are not too badly priced i just may add a second switch on the black Negitive side and run a homemade mechanical on/off shaft to operate inside the car. This way I will have one inside and one under the hood. I also needed to extend my wires on the regulator as these. Brown and Tan 10G Blue 16g And a couple Reds 10g Where can I get a couple feet of each, or yet which is safe to use if it not AWG?
Posted on: 2016/10/16 14:28
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The best are yet to roll
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Re: Cut off switch for 6v positive ground?
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Just can't stay away
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This is what I did so far.
Note; That switch will change and the bracket will too, till I can make a custom bracket. Also the black wire shrinks will be covered with red ones once I get them. That is until I find the file.
Posted on: 2016/10/16 15:29
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The best are yet to roll
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