6/12 Battery Set-Up For Starting

[61polara]

I just purchased a 1941 Lincoln Continental Coupe that has a 6/12v battery set up using two 6v Optima batteries, a huge solenoid and some form of electrical unit attached.  I'm use to the set up of the old 6/12v batteries with two 6v batteries in one case with a solenoid on top of the case to connect the two for 12v starting and 6v running.  Is someone selling this setup so I will know where to get replacement parts.  Also, what is the purpose of the electronic unit beside it.  It appears to have diodes inside it.

[Matt Harwood]

My guess would be they built that Mickey Mouse setup to compensate for the puny battery cables because they didn't understand how voltage and amperage work. I have a '47 Continental that starts quickly and easily, hot or cold, on 6 volts. Fat cables and good grounds are the key. Ditch all that goofball wiring and the crimp-on connectors, get some big, heavy battery cables, and just one of those Optimas will start that engine reliably. If you want a big hit of amperage, hook them up in parallel to get 1600 amps to crank it over--that sucker won't be able to NOT spin with that kind of juice hitting the starter. Lose the 6/12 setup and the wonky wiring and switches. Your life will be simpler and easier for it.

 

 

Edited June 13, 2020 by Matt Harwood
You're/your? Really? I made that mistake? Bleh. (see edit history)

[edinmass]

Matt is 100 percent correct. 

[maok]

Agree, get rid of that messy setup. Your engine and starter won't use all of that 1600amps that the optimas can supply, probably around 300-400amps, maybe more if that is a large capacity engine, and suspect it is.

[61polara]

Actually this setup was rather well done.  Large 6v cables carry the voltage to the starter.  I do plan on removing it.  This may have been done to power a 12v aftermarket radio installed years ago, which I plan on removing as well.

[edinmass]

I’ll give the guy credit he got it working.......well done? Not at all. Look at the cables and how they attach, and the battery terminals. Crimp on connectors? More hack work. Battery hold downs.............the hole thing was poorly executed, designed, and installed. You have 500 dollars in batteries, and they couldn’t get cables with terminals soldered on.......you get the idea. Having custom cables made is very inexpensive..........having rebuilt engines like this one, they have always been finicky to get right, and the starters always seemed to turn slow. That said, properly set up they were very reliable and an enjoyable car to tour with. My guess is when you switch it back, you will find the “issue “ that caused the 12 volt change over. Be prepared to deal with it. The battery set up was providing 1600 amps cranking.........hopefully the starter wasn’t subjected to much load of it might have been scorched or turned into a toaster. It would probably be a good idea to do a draw test on it before you take it apart. Anything over 200 amps 12 volt will probably indicate hidden things inside the starter.

[Matt Harwood]

Those are not large cables. 6V cables should be at least the diameter of your thumb. Do not re-use them. I would also dump those goofy battery terminals with the wing nuts and have proper cables made with correct terminals. It's also a good idea--especially on flathead Fords and Lincolns--to add another ground cable from one of the starter mounting bolts to the battery ground point on the frame.

 

Here's the dual Optima setup for my '35 Lincoln K, which, the 2 or 3 times I actually drove it, kicked that big engine over with extreme vigor, hot or cold.

 

 

[PFitz]

Another vote for what Matt said.

 

12 volt system wiring is easy and cheap,..... 6 volt systems take more work and wire.

 

OO size cable (double zero) and soldered connections is standard for 6 volt battery/starter systems. Anything less will not pass as much amperage.  Clamped connections will not easily pass as much amperage as a soldered connection and will often get hot with the added resistance when forced to.  Clamped connections with cables that are too small is twice the problem.

 

Think of electricity is like water - voltage is like water pressure and amperage is like gallons per minute. When you need a lot of water at a certain pressure and gallons per minute, using too small a pipe won't be able to do it unless you raise the water pressure to an unsafe amount.

 

You can get 6 volt cables, all with the proper sized soldered-on terminals, from Rhode Island Wire Service. Even if you need the cables custom made, they can do it and at reasonable cost.  And when they are done, it looks like the original cables, not like some weekend mechanic using the obviously wrong modern stuff.

 

Paul

[60FlatTop]

I was just heading out to the garage for the rest of the day. I sure feel like I can handle anything that comes along after seeing those pictures.

 

Check the right front fender for paint repairs from the big steer horn belt buckle rubbing on it.

[MCHinson]

Dave,

 

I agree that putting it back to orignal with proper cables is the best thing to do. One other thing in the photos that makes me scratch my head is the ground wire attached to a head stud. While an extra ground is a great idea, I have never seen anybody that chose to attach one to a head stud.    

[edinmass]

Any of the nationally recognized wiring harness companies can provide correct cables. The tractor company that starts with a “B” who’s name escapes me, makes cables that are fantastic, and very, very reasonable if you have a sample.

[Terry Harper]

On 6/13/2020 at 6:45 PM, edinmass said:

Any of the nationally recognized wiring harness companies can provide correct cables. The tractor company that starts with a “B” who’s name escapes me, makes cables that are fantastic, and very, very reasonable if you have a sample.

 

Brillman Ed?

 

https://brillman.com/wire-harnesses/

 

 

 

 

Edited June 15, 2020 by Terry Harper (see edit history)

[edinmass]

Thats them!👍

[61polara]

Guys, thanks for all your replies.  I have a local battery shop that can make up the correct cables for me.

[Akstraw]

I wonder sometimes if setups like these are driven by a desire to hear the vintage 6v starters spin as quickly as those in the modern cars to which we are accustomed.  A slow spinning starter does not necessarily mean there is a defect.  Those of us who have crank-start vehicles know that the objective during starting is not to bring the engine up to speed; it is merely to get one cylinder to fire.  The engine will take it from there.  If the starter cranks for too long a time before the engine fires up, it may be that the car has a non-starter issue.  Agree with the recommendations above that best course of action is to return the system to stock and troubleshoot from there.