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Real Steel

Installing A Battery Cut-Off Switch In My 1930 Pickup (Photo Heavy)

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A few days ago I replied to an AACA General Forum thread titled "safety - battery cut off switch".  In my reply I showed a little bit of the cut-off switch that I installed in my unrestored 1930 Ford pickup.  Since then I've received some requests to add more information about how the installation was performed.

 

For the most part, installing a cut-off switch is fairly easy, especially for most of the folks on this site.  The key to my switch...the thing that makes it different than most...is that the switch is mounted on the floor near the driver, and the switch is surrounded by a bezel that makes the switch look like it's supposed to be there (in my opinion anyway).  On top of that, the floorboard is still easily removed without removing the switch or cables.

 

This is not a set-up for cars that will be judged.  You're on your own if you're going that route.

 

Before I post the 14 photos that I selected for this, I have to tell you that the bezel was hand made from an old thin metal ashtray.  Some folks get a bit put-off at the idea of hand fabricating something, but trust me, it was pretty easy.  You will spend more time on eBay searching for a proper bezel candidate than you will spend fabricating the actual bezel.

 

Rather than explaining everything in advance, I will just post the photos.  I think the photos are mostly self explanatory, but you are welcome to ask questions and I'll do the best I can.

 

One last thing:  I didn't modify or damage any original parts of this vehicle.  I did not permanently modify anything.  I drilled no holes; I used only existing holes...with the exception of the plywood floorboard (which is an older after-market part).  I encourage you to use similar discretion in how you install the cut-off switch in your piece of history. 

 

 

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Edited by Real Steel (see edit history)

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Thanks for providing this information. A very elegant solution.

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Recessed is important inside the cab/car. I have seen switches accidentally kicked into the off position while driving down the road, causing lots of problems. With the early mechanical foot pedal starting systems, you only need to switch the harness not the starter, greatly reducing the amperage load on the switch. A much better solution when possible/convenient.

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That's true Ed, but I installed a battery cut off switch in the '40 Buick AND the '31 Imperial ( both foot starters) to take the battery completely out of the system.

I wanted the battery completely isolated while in storage or transport.

Now I sleep well at night.

 

Mike in Colorado

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Mike.......I get your point. I have seen switches fail after long term use from high amperage draw............not many switches handle 800 or more amps well over time. I recommend carrying a spare if you drive a lot. 

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Ed, I have been using a heavy duty cut-off (which is a little hard on the fingers, but moves some power through the car).  I accidentally threw the box away from the last one, so do not have a part number, though did a quick search and found such as this.  I stumbled into the heavier switch when walking through the racing department of our local Pep Boys (at one time they carried both types and just caught my eye).

 

https://www.amazon.com/Fastronix-Severe-Master-Battery-Disconnect/dp/B07L2JRHRQ/ref=pd_sbs_263_t_1/134-7750251-9655536?_encoding=UTF8&pd_rd_i=B07L2JRHRQ&pd_rd_r=bc562775-3c4c-4324-908c-547a8ed2789d&pd_rd_w=ikzgR&pd_rd_wg=HShLk&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=2SMTG4ZD1NGJ1ZJND97G&psc=1&refRID=2SMTG4ZD1NGJ1ZJND97G

 

https://www.amazon.com/Cole-Hersee-75908-Silver-Disconnect/dp/B001FQNI9I/ref=asc_df_B001FQNI9I/?tag=hyprod-20&linkCode=df0&hvadid=241973068692&hvpos=1o8&hvnetw=g&hvrand=6584075452439214703&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015702&hvtargid=aud-800640527683:pla-583135075371&psc=1

Edited by John_Mereness (see edit history)

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I agree with Ransom Eli: A very nice, elegant solution.  Thanks for posting the photos and your comments.  (I like the truck, by the way.)

 

Phil

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4 hours ago, John_Mereness said:

Ed, I have been using a heavy duty cut-off (which is a little hard on the fingers, but moves some power through the car).  I accidentally threw the box away from the last one, so do not have a part number, though did a quick search and found such as this.  I stumbled into the heavier switch when walking through the racing department of our local Pep Boys (at one time they carried both types and just caught my eye).

 

https://www.amazon.com/Fastronix-Severe-Master-Battery-Disconnect/dp/B07L2JRHRQ/ref=pd_sbs_263_t_1/134-7750251-9655536?_encoding=UTF8&pd_rd_i=B07L2JRHRQ&pd_rd_r=bc562775-3c4c-4324-908c-547a8ed2789d&pd_rd_w=ikzgR&pd_rd_wg=HShLk&pf_rd_p=5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=2SMTG4ZD1NGJ1ZJND97G&psc=1&refRID=2SMTG4ZD1NGJ1ZJND97G

 

 

300 amp starting at 12 volts.................it's easy to pull 800 amps on a six volt big car............I won't get into voltage drop under load to the coils when cranking for extended periods of time............

Edited by edinmass (see edit history)
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11 minutes ago, edinmass said:

 

 

300 amp starting at 12 volts.................it's easy to pull 800 amps on a six volt big car............I won't get into voltage drop under load to the coils when cranking for extended periods of time............

That is the issue !  I will keep researching - I know I found something more appropriate, but have not dealt with the issue in a couple years (and hate to say it but most stuff I have touched recently has the smaller lighter duty ones and I have been more frying other fish).  

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Very nice. By the way that appears to be a very rare Tiffany ashtray.   Quite valuable. But I suppose you could say its now full of potential.

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The second switch, the Cole-Hersee, is rated 2000a intermittent. Would that work with 6 volts?

 

Dave 

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I have seen so much trouble with cutoff switches on smaller 12v cars, that I hate the idea of using them at all let alone on 6 volts.

 

1 hour ago, Dave39MD said:

The second switch, the Cole-Hersee, is rated 2000a intermittent. Would that work with 6 volts?

 

Yes, because it is the current that matters, and you need twice as much of it to do the same work at 6v (when compared to 12v). Big Cole-Hersee switches are used in fire trucks. Thats about as good as it gets. However, the one in the link is not so big and is rated 300A continuous. The 2000A rating, while plenty, is for intermittent duty, and while starting is indeed intermittent duty, the rating makes the switch sound a lot bigger than it actually is.

 

Edited by Bloo (see edit history)
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It might have been a good idea to have checked the markings on the bottom of the ash tray and to have determined its value before it was torn apart.

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On 10/20/2019 at 4:56 AM, edinmass said:

 

 

300 amp starting at 12 volts.................it's easy to pull 800 amps on a six volt big car............I won't get into voltage drop under load to the coils when cranking for extended periods of time............

 

Next time you start your car, stick a DC amp clamp meter over the starter cable, you will be surprised how little the starter needs regardless of 12v or 6v, especially a well tuned engine. Amps drawn is very similar regardless if its 6v or 12v.

Edited by maok (see edit history)

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A Pierce 12 or a Cadillac 16 with a good motor will draw 400-600 amps when hot, and around 300-350 cold. I have tested them many, many times. Cars with poor starters, wiring, bad grounds, Ext........often will draw 800-1200 Amps.

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19 minutes ago, edinmass said:

A Pierce 12 or a Cadillac 16 with a good motor will draw 400-600 amps when hot, and around 300-350 cold. I have tested them many, many times. Cars with poor starters, wiring, bad grounds, Ext........often will draw 800-1200 Amps.

 

Yes, 12 or 16 cylinders would draw hell of alot more than a 4 or 6. My point is 6volt or 12volts will be about the same current draw.

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Actually no. All else being equal, it takes twice as many amps at 6 volts as it would at 12 to do the same work.

 

.Watts DC (Power) = Volts x Amps

 

 

Edited by Bloo (see edit history)

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1 hour ago, Bloo said:

Actually no. All else being equal, it takes twice as many amps at 6 volts as it would at 12 to do the same work.

 

.Watts DC (Power) = Volts x Amps

 

 

Not with an electric motor Bloo.

The higher voltage drives the motor faster, the current is used to over come the mechanical resistance.

Edited by maok (see edit history)

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11 hours ago, Bloo said:

Actually no. All else being equal, it takes twice as many amps at 6 volts as it would at 12 to do the same work.

 

.Watts DC (Power) = Volts x Amps

 

 

 

Agreed. 

That's why a 6v starter motor will require cables that are larger than a 12v starter...to carry more current.

Edited by Real Steel (see edit history)

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13 hours ago, Bloo said:

Actually no. All else being equal, it takes twice as many amps at 6 volts as it would at 12 to do the same work.

 

.Watts DC (Power) = Volts x Amps

 

 

Yup, and Pie   R    round !

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