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.  This is also posted in the AACA Technical Forum.

Edited June 13, 2020 by 61polara
Additional info on car. (see edit history)

[Ray500]

Basically you are running the car off one of the 6 volt batteries.  You are putting the 2 in series is for starting the vehicle.  Running 12 volts through the starter too much can overheat it if over utilized.  The 2 diodes are for charging both batteries from the 6 volt generator/alternator.  The diodes offer isolation from the batteries and still get a full charge to each battery when the engine is running.  A new alternator (6 volts) will work best without all the regulators of the old generators.  Alternators have built in regulation.  I can draw you a simple diagram later on how to hook it up.  

 

If your engine is in good tune,  easy to start, and you are using 00 gauge cables on the battery and starter with very good grounds, a 6 volt system with a 6 volt alternator as I have on my 41 works well without having to rig up 2 batteries.  At 6 volts the starters usually pull some 200 + amps when energized, and that's easy for the Optima as it puts out some 800-1000 amps under full load fully charged.  Using 12 volts it should need about 50% of the current, but remember you're using a 6 volt starter so the current will be a bit higher, no real problem with the 12 volt setup other than overheating it.  Lots to consider!  

[edinmass]

The two batteries are installed for only one reason. The mechanic who was working on the car didn’t know what he was doing, The car was fine as built. Since they couldn’t figure out how to fix a slow or hard start problem.........could be fuel, ignition, starter, wiring, ect.......they did a terrible job at installing a 12 volt set up. The wiring and connections show lack of skill and understanding of proper basic electrical Service. It should be removed, put back to stock, and properly fix the issues that started this mess. 

[61polara]

Thanks for your comments.  I just wanted to put this out here for comments.  I had already planned on removing it as well as the 12v radio which was installed.  Does anyone have a correct radio delete plate for a '41 Continental?

[19tom40]

When you remove it, be sure to replace the battery cables. The current cables are 12 volt cables. The radio delete plate may be hard to find as they were usually discarded when a radio was installed.