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Battery 37 special


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So I just put the 37 special on the road!

did a few KM on it.


I think I may have a Generator issue,  but my questions is more related to the battery.


I bought a 6v Optima battery and have it installed -  the car turns over very slow and will sometimes start with it other times not.(when full charged)


But if I put a 6V 40amp boost it fires up almost all the time


Should I look at a second battery for the car?  Series or Paraelle?


Or has there been issues with the Optimas not having enough power?

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Obviously if your generator is not charging, you need to fix that. Other than that, I would disassemble and clean all of the contact points in the starting circuit. Also, make sure you have the correct 6 volt battery cables. If someone has changed to the 12 volt sized battery cables available off the shelf at a local auto parts store, they will not flow enough current as they are undersized for a 6 volt system. I have no personal experience with Optima batteries. I bought my 6 volt battery for my 1937 Century at Tractor Supply for $80.  

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My 1937 Roadmaster starts just fine NOW on a single OPTIMA 6-Volt. Originally the car was perfectly ok, and the prior owner replaced a Group-2 battery and new (but modern lightweight) cables. These modern cables were removed and replaced with 000 (Triple Aught) braided cable with soldered ends. The 320 ci  Buick engine spins over as it was intended. The Optima spec is 1000 Cranking Amps.


When I first bought my 1941 Cadillac it had a pair of Optimas in Parallel, apparently to make up for having the wrong cables. I still have a pair of Optimas there - unnecessary in my opinion, - but with 000 cables, this car also has no starting issues, even when hot.

Edited by Marty Roth
typo (see edit history)
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It appears as time goes on they are downgrading the 3EH Battery.  The current one I am using is a Transcontinental with 925 cca I purchased in 2003.  It still takes and holds a charge. I am sure of the age as I found the receipt as well as the punch tag on the battery.  I could not find the paperwork but I believe the one it replaced was over 1000 cca.

My current battery had a 3 year warranty.  I don't see any listing more than a 1 year warranty. The 2003 receipt shows a new positive cable. He didn't list the size but I believe he called it welding cable and it is as thick as a finger.


I have checked on the internet and the best buy appears to be the Exide Heavy-Duty Farm Battery F3EH from Tractor Supply at $99.99.  It has 875cca but 1020 cranking amps, 20 more than the Optima and it fits the stock battery box.  NAPA still lists the 2E at 620 cca for $149.95 but the 3 EH will fit and at least spins mine like a 12 volt.

The 3EH is a commercial battery with several suppliers so one can most likely find one near their home.


I have owned my car for 47 years and used several battery manufacturers. I have always checked the water, used distilled water and stored the battery indoors out of the car when in winter storage. Knock on wood all have exceeded warranty limits by several years.  



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