Topic: Battery Disconnect Switch


36fordor    -- 07-28-2017 @ 8:10 AM
  Should battery disconnect switch on six volt positive ground go on positive or negative post?

Any specific recommendations on quality switch?

Thanks.


JT Ford    -- 07-28-2017 @ 9:05 AM
  Use the + post (ground) Those green knob switches are ify! One car it seem to work and other one had a lot of trouble. Car would just not start with out fooling with the connections. I removed it and no more trouble. I just remove the cable to kill.


len47merc    -- 07-28-2017 @ 10:37 AM
  Check out this discussion from our Forum last year. Been using it ever since - it works great. Good Insight from a couple of senior guys here on the Forum as well.

https://www.earlyfordv8.org/forum/viewmessages.cfm?Forum=18&Topic=9482&keywords=battery%20disconnect

Steve


4dFordSC    -- 07-28-2017 @ 10:38 AM
  I've used a knife blade disconnect on an Optima battery for a number of years with no problems. Although it's theoretically safer to connect it to the ground terminal (i.e., positive on a flathead Ford), mine's on the negative terminal because it fits better there. You can can find them listed under "knife blade battery disconnect" on Amazon.


sarahcecelia    -- 07-28-2017 @ 1:28 PM
  Those green knob disconnects are JUNK!! When thet stop working, you have to take the knob off and clean the contact points. they corride every time you open and close them! Just disconnect the hot terminal on your battery and your all set!


len47merc    -- 07-28-2017 @ 2:45 PM
  That's been my understanding as well, not only from responders on our Forum but from 2 neighbors using them on a '56 Chebbie and '54 Chrysler - both experienced similar 'failure' modes with the green knob option, one ('56, 12V) has now switched to the NASCAR-style red-key option mounted through a new hole drilled in the firewall, the other ('54) 6V pos ground to the 'blade' like the one referenced my earlier post above. Both are satisfied.

To my knowledge very few options can handle (according to their performance ratings) the amperage levels required of 6V systems other than the Wirthco blade options, but many here and elsewhere have experienced satisfactory results with other manufacturer's solutions. Whatever works best for you. Some like the green knob, but most I associate with loathe them and prefer the simple manual disconnect option as most effective for peace-of-mind.

Personally if I ever - and I mean ever - even once - experience a concern with my chosen blade option I'll gladly go back to simply opening the hood and disconnecting the battery with a 1/2" open/closed wrench. Did that for several years and it never failed me and never was a bother to deal with. Fwiw.

Steve


nelsb01    -- 07-28-2017 @ 3:59 PM
  Definitely use the+ positive side. If it contacts with any thing -- like battery hold down etc there wont be a lot of sparks.
Now, I have had one of those green things on my Ford for over 20 years. First look at the one you are going to buy. There are $5 ones and there are $20 ones.
I believe those that mentioned that they are junk got the lower side of $20.
You do have to make sure that your battery terminals are clean. I also use a coating of grease on the terminals to help prevent corrosion.
Everyone has a different situation -- this worked for me.


Drbrown    -- 07-30-2017 @ 9:35 PM
  Had the green knob type on my '47. I frequently had to tighten the cable-clamp connection. I also got tired of opening and closing the car hood, especially in bad weather, and hitting my head on the hood, so I installed a high-amp capacity rotary-type switch on the firewall, with the actuating knob on the inside, out of direct sight, next to the heater.

This is a particularly good location for a shut-off in case of an emergency while driving. I have the 4-terminal type which also disconnects the generator or alternator.


supereal    -- 08-01-2017 @ 2:50 PM
  I have had a "green knob" on my '47 for over 20 years with no problem. It is installed on the "hot" (negative} battery post. It is an inexpensive way to protect the vehicle from fire. I don 't mind turning on it when I use the car, and turning it off when done prevents discharged from electric wound clocks and other accessories.


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