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1941 6V to 12V - Buick Special 40 Series


Turbosl2
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Is there an easy way to convert these to a 12V system without spending at boat load of $$. I am tired of the industrial 6V tractor batteries from Napa. They cost $300 and last 3 years at best, i keep a tender on it and it just doesn't seem to last. I only drive this car 500miles a year at best and the batteries are junk.

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I'm not convinced a switch to 12V is a solution to this particular problem and will bring its own batch of problems that will be frustrating and more expensive to solve. An Optima might last longer. Also make sure your electrical system is healthy and it might help keep the batteries alive. Stray drains or bad grounds or a generator that's not performing up to par can all reduce battery life. The store-brand $140 group 3EH battery in my '41 Limited is coming up on six years old and still works just fine--I can have my car running in less than 5 seconds and it kicks over easily hot or cold. It's not that the batteries you're buying are necessarily bad, it's the stuff around them that might not be working at peak efficiency.

 

Giving your existing electrical system a tune-up will be cheaper and more effective than a 12V upgrade. I'd start there instead of reinventing the wheel.

 

 

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Well,  both groups will have their own thoughts.     If you want that change,  just stand back and watch the comments.    If you are going to 'show' your car - it becomes 'modified.   I personally prefer 12 v  because -  I like to drive my Buicks  ( two now )and -  failure of electrical systems while on the road can be problematic.   Very few items of any value need to be changed.   12 volt batteries are readily available.   Yes I got tired  replacing 'hard to find 6 volt batteries that fit.     Starter remains the 6 volt unit.   The original points and condenser don't care.   The ignition coil is available at any parts store.  (Cheep).   The generator needs changing to 12 volts.   I put in a 70 amp alt to give me all I need.   That is usually changed to an alternator and again readily available with a failure (? When have you had a alternator failure).   Minor wiring to use 3 wire electrical.   All the light bulbs are available as 12 volts.    Didn't Buick change over to 'modern' head light bulbs ?   12 volt units are available.      Thus, that is all you need to do it.   Small pain going under the dash to get to those few that are there.    I just plug in my GPS and my iPhone .    I also added LED (all 12 v ) tail lights to run in parallel with the original brake / tail lights that even changing to 12 v are very week.    In my world, safety items come first !     In my opinion,  it is not very expensive to convert.    'Jumper cables' are no biggie if necessary.   ( No body will have  6 volt batteries if you need a jump.)..   My longest trip was 1800 + miles from  Tampa Fl. to the Nashville Tn and back.    BTW,  have you added a fuel boost pump ?     Very important item !  

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Matt's solution is important.   Keeping your battery on a trickle charger when not using it.   If you don't drive a lot,   Matt's solution is great.    I drive 1000 to 1500 miles a year so being on the road brings different issues.  Mechanics in the road are ignorant of our old car  6 v systems.   So that is one of my bigger reasons to going 12 v system.    Here is my latest Buick.   1935 - 58 Vicky.    You can see how I tucked the alternator in place of the original 6 v generator.  

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I use 6V Optimas. I’ve had them last 15 years, 12 years, and then I had a bad one that was good for 18 months. So there is a range.

 

I also agree with Matt. The conversion to 12 V is not trivial, and will create a whole set of other issues. It’s not a holy war, it’s just fact.p

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I agree with Matt in that a 6-volt system if properly maintained can be reliable and able to start the vehicle in most temperature conditions.   I use the 3EH battery from Tractor Supply that is slightly bigger than the original 2E but fits in the tray and the cover.  This battery is supposed to supply 875 Cold Cranking Amps.  I use "OO" battery cables and always put it on the Battery Tender when I return from a trip.   Once the green light on the Tender shows the battery is fully charged, I remove the charger cables or shut off the Battery Tender.  I also use a heavy-duty battery kill switch that I turn to off when not running.

In all my years of experience with various battery chargers and maintainers I have seen batteries cooked dry when the chargers are left connected after reaching full charge even though the manuals suggest otherwise.

I also always use distilled water when needed to top off each cell and check the state of charge during the cold months and leave the Battery Tender on until full charge is reached.   When I get a clear day with no salt or snow on the roads, I drive the car for at least 45 minutes.   I never just start it up and idle it for a few minutes.

Joe, BCA 33493

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Switching to 12 volt is NOT the solution to your problem. A properly working and maintained 6 volt system is just as reliable as a 12 volt system. Parts availability is slightly more problematic... If I were that worried about parts I would simply have a spare generator and regulator in the trunk ( test them BOTH first on the car). Generators and regulators are both very reliable. As for the battery, an Optima and a GOOD tender will outlast any lead acid 12 volt battery or 6 volt for that matter.  Just my $.02....

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Sorry, Matt and Alsancle, I disagree with the "whole set of other issues" thing.  Like Jim, I changed mine 12 years ago.  20,000 miles plus. NO ELECTRICLE problems.  The 6V starter did give out after a few years, probably due to the increased compression of the engine.  Broke the drive gear. Otherwise, no problems None.  

 

  Turbos12,  message me if you like and I will be glad to exchange phone # and talk through the process with you.

 

  Ben

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On 9/7/2022 at 7:14 AM, Matt Harwood said:

I'm not convinced a switch to 12V is a solution to this particular problem and will bring its own batch of problems that will be frustrating and more expensive to solve. An Optima might last longer. Also make sure your electrical system is healthy and it might help keep the batteries alive. Stray drains or bad grounds or a generator that's not performing up to par can all reduce battery life. The store-brand $140 group 3EH battery in my '41 Limited is coming up on six years old and still works just fine--I can have my car running in less than 5 seconds and it kicks over easily hot or cold. It's not that the batteries you're buying are necessarily bad, it's the stuff around them that might not be working at peak efficiency.

 

Agree, we've had an 6v optima battery on a 26 buick that's used periodically for about 8 years now, and it's worked great - as long as there is gas in the carb it starts instantly hot or cold

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  • 1 month later...

All three of my cruiser cars,53 super restomod, 52Ford f1 and 40 special have150 amp powermaster alternators and optima red tops. I use the optima battery tender for maintaining. The ford and 40 have 6V starters and they zip to life. No problems. The 40 spins so fast that you can crank it in low and by the time it fires you can shift to second. All 3 had new wiring front to back. It's really the best way to go.

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On 9/6/2022 at 5:15 PM, alsancle said:

I use 6V Optimas. I’ve had them last 15 years, 12 years, and then I had a bad one that was good for 18 months. So there is a range.

 

I also agree with Matt. The conversion to 12 V is not trivial, and will create a whole set of other issues. It’s not a holy war, it’s just fact.p

I agree with alsancle - similar experience

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