Master battery disconnect switch

1941 - 1945, MB, GPW modifications, sugestions, and ideas, official MWO's and unofficial WWII field mods NO EBAY or COMMERCIAL SALES.
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pkozak1
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Master battery disconnect switch

Post by pkozak1 » Mon Apr 17, 2017 8:12 am

Does anyone use a Master Battery Disconnect switch? If yes, what type? Pictures if at all possible please> Thank you.

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artificer
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Re: Master battery disconnect switch

Post by artificer » Mon Apr 17, 2017 10:56 am

I used to & it was a marine type thing & needed a key to re-activate something like this but better quality....
https://www.amazon.com/dp/B01IBOH5EA?psc=1
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Master battery disconnect switch

Post by Wolfman » Tue Apr 18, 2017 5:34 am

I have seen two types. The one shown in John G's link ( with and without a key ) and an open knife switch type.
They can be bought at any auto parts store or I think I saw them at Harbor Freight.
The custom cars show guys use them as a safety factor. When they drive baby to a show, the switch is a quick, easy way to disconnect the battery while the car or jeep in your case is on display. They hide them where they can get to them but not obvious to an on looker.
Keeps some body from doing something they shouldn't ( Not that anyone would do that :roll: ), like accidently hitting the starter or starting the car or jeep and hitting people and other cars around them.
I would used the enclosed one in your case. Less likely to have something fall on it and short out.
Hint: they work on the ground side as well as the B+ side of the battery.
Mike Wolford
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pkozak1
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Re: Master battery disconnect switch

Post by pkozak1 » Tue Apr 18, 2017 6:47 am

Thanks, I was going to use it on the ground side just in case something did touch it, it wouldn't short.

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Fred Coldwell
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Re: Master battery disconnect switch

Post by Fred Coldwell » Tue Apr 18, 2017 5:52 pm

I simply remove the ground (-) battery cable whenever I'm not going to fire up the jeep the next day. This allows me to clean off any corrosion on the - battery cable clamp or the - battery post each time I re-attach the - battery cable for use that day. Detaching and re-attaching the - battery cable with my standard length 1/2 inch SAE wrench avoids any risk of accidentally grounding that wrench to the jeep when removing the + battery cable, which would produce a dead short and large sparks if the - battery cable is not removed first.

I leave the positive (+) battery cable attached all the time, except for twice a year, when I remove it to clear corrosion off the + battery terminal and + battery cable clamp. Before removing the + battery cable, I double-check to MAKE SURE the - battery cable has already been detached so I do not accidentally ground the metal wrench from the + battery cable to anywhere else on the jeep, producing a dead short and those terrible large bright sparks.
Happy Jeep Trails,

Fred Coldwell
1944 CJ2-09 - X33
1945 CJ2-26 - X50
1944 Dodge T233 CC
1945 Dodge T233 Utility
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artificer
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Re: Master battery disconnect switch

Post by artificer » Tue Apr 18, 2017 6:25 pm

John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: Master battery disconnect switch

Post by Seff » Tue May 09, 2017 8:02 am

artificer wrote:I used to & it was a marine type thing & needed a key to re-activate something like this but better quality....
https://www.amazon.com/dp/B01IBOH5EA?psc=1
I have something of a similar design but installed by the French army. It disconnects my battery + from all other connections. The alternator and the large + supplying the dash (through the amp meter) both connect to this, with the battery + on the other post. It's hidden under the dash, in the passenger side - I can still reach over and flip it, though.

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Martin MB in UK
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Re: Master battery disconnect switch

Post by Martin MB in UK » Mon Jun 12, 2017 11:07 am

This is what I use. Mounted behind the air cleaner so you cant see it, and up behind the dash. Small chain on the red key, mounted so when the key is in, it is horizontal, and a small tug on the chain pulls the key down and out, in case you need to disable the battery quickly. Never had any problems. If you want a photo, I'll get some, my air cleaner is out at the moment anyway.
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Re: Master battery disconnect switch

Post by pkozak1 » Wed Jun 14, 2017 5:45 am

Thanks.

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Martin MB in UK
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Re: Master battery disconnect switch

Post by Martin MB in UK » Wed Jun 14, 2017 10:43 am

This is what it looks like when the air cleaner assembly is off. The little orange cable goes to a 12v cig socket under the dash. big cable from battery to switch, then the other big cable to the starter floor button. Simple.
trying to upload a pic. Just be careful when putting the air cleaner back in, that you don't touch the 2 terminals, get a bit of a spark. It clears it no problem, only sparked once, learnt to be a bit more careful after that.
bms2.jpg
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Martin Russell
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Near Beela POW Camp
'42 Willys MB 163086
'65 Mustang 2+2 V8
Fat Bob Harley

pkozak1
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Re: Master battery disconnect switch

Post by pkozak1 » Thu Jun 15, 2017 5:39 am

Cheers!

Rod Rushton
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Re: Master battery disconnect switch

Post by Rod Rushton » Fri Jun 23, 2017 8:20 am

I use a simple cut-off switch which works with a bridge screw, which you can undo and carry in your pocket - no holes to drill and not expensive
see e-Bay #111732970085
P1010013.JPG
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FORD GPW 202055 DoD 5 - 22 - 44 Serial# 20534360
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Gordon_M
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Re: Master battery disconnect switch

Post by Gordon_M » Fri Jun 23, 2017 11:06 am

If you want a contemporary switch I used the one from the Weasel dash which was ideal.

One thing though, all these switches have a voltage drop, I measured almost 0.5 volt. That's fine on a 12v or 24v system, but when you are only starting with 6v you may be better off just pulling a battery terminal clamp off.
Gordon

1939 TD20 Pickup
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1941 Highway Trailer K-38
1943 Ben Hur
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1944 Saginaw M19 ski trailer x 2
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pkozak1
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Re: Master battery disconnect switch

Post by pkozak1 » Mon Jun 26, 2017 5:38 am

Ok, thank you.

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