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My '47 is still the original 6 volt system. It has not been a big deal except that the 6 volt batteries I have been getting do not last long (NAPA, industrial) so I have been thinking about converting to a 12 volt system. Now days the 6 volt turns over slow and sometimes it hard to start. So I am looking for some guidance on this.
I have had the truck for about 10 years now. My wife and I enjoy tooling around in it.
Hi there, I have just completed an engine rebuild and part of the job included swapping to 12 volts. I changed the generator to a 12 volt alternator ( in a generator housing to look old school) put in a new crab dissy, starter solenoid and coil. I also swapped out the mechanical fuel pump for a 12 volt electrical one. You also need to consider inside the cab as the gauges all run on 6 volt, and in my case I put in a control voltage regulator that changes the input to the gauges down to 6. As far as all the lights are concerned, change up the bulbs and I think that's about it.
Certainly turning her over with a 12 volt system gives you much more confidence than the old 6 volt "pray she kicks" system.
Welcome to the site. That is a very nice looking truck you have there. Bill pretty much covered all the basics of the conversion. When I did my conversion I used Runtz for the temp, gas, and oil gauges.
Another alternative is to install 2 - 6 volt batteries in series and use a 12 volt alternator. You can leave the truck gauges as they are and still have a 12 volt system for upgrades like radios and air conditioners. You can even run your 6 volt starter on 12 volts for that extra little umph.
I didn't want to mess around with the generator/regulator original configuration so I replaced both with a 6v alternator. Drained or boiled battery problems are solved. Yes, it still sounds like it will never start but does. Still working on the proper sized cables for the amp load to the starter.
This is my first year with a 1940 95 hp flathead with the original 6 volt generator. I have not started it very often or driven it very much, but it always cranks enthusiastically. Sometimes I have to crank it several times before it starts, but it never sounds wimpy. I installed a battery cut-off switch from Advance in the firewall with the key under the glove box, 2 gauge battery cables from NAPA, cleaned all the old connections thoroughly, and used GB Ox-Gard on all the connections to prevent oxidation. And "knock on wood" it works. Just two cents worth from a very raw newbie.
Once you have a few old 6 volt trucks sitting in sheds and always a new project beckoning you will be glad for all the ones you converted to 12 volt neg ground. I use a chev one wire alternator on a slingshot bracket, just sitting out there for all the world to see(if they pop your hood) and I have NO regrets. If you should sell it one day the new owner can put a 6 volt pos ground generator on it if he chooses to. In the meantime, I like them to fire up if and when I need to use them. Just my .o2 on the matter.. I have a friend who HATES that I run the GM alternator on my old V8s. Somdetimes I think that's 1/2 the reason I do it....
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1947 Pickup 12 volt conversion questions
