The Stovebolt Site Forums The Shop Area The Electrical Bay 6V to 12V Conversion

After 15 years of waiting, I am finally purchasing my dream truck, a 54 chevy 3100. The truck I am getting is a 6V system and I will need to convert it over. I have no idea how and where to start on it.

Is there any suggestions?

Search the topic here on the site you should find all you need to know. It is all covered in a Tech Tip as well. It is easy, 12-volt battery, bulbs, Alternator or generator, gas gauge resistor (some will say unneeded but mine fried when a Runtz resistor failed), 12-volt coil I use one that has the internal resistor others use a ballast resistor on the firewall, 12-volt voltage regulator. If starter is good it will work fine, so will the horn. If you have new wiring there should be no issues, usually truck wiring if original may have issues so if you use it check it over. That is about it I think. Oh and best of luck with your truck, oh and in your search you will also find a group that loves the 6-volt and will question why the change.

for what reason? all three of my trucks are still six volt and there are no issues with mine to warrant changing anything.

There is a 12v conversion Tech Tip (look at the Tech Tips link near the top of this page).

Do you need to change to 12v because you want to use 12v accessories?

I'm on board with 51 ashton. Is it a "need" or a want? Unless you're going to run some high power accessories converting to 12v isn't really necessary to have a well functioning vehicle.

Ditto. Converting to 12V was on the top of my list when I purchased my truck. I can't think of a reason I would change from 6V at this point. Truck starts great, battery stays charged and all my accessories, including the original radio work fine. I especially appreciate the slightly dimmer headlights - they authenticate the truck and I really don't drive it much at night.

If it ain't broke, don't fix it seems to apply here. I'm certain you will find ways to spend the $$ somewhere else.

I have no reason to disagree with the keeping it 6 volts. Except in Kansas in the wintertime, let alone anywhere further north, it wont start below 20 degrees. Of course nowadays most of us have garages that are usually above that temp. 12 volts overcomes this issue with power to spare. I know the passion involving this issue, I have lots of friends that shake their heads when I say the above. None of them live in north North America and desire guaranteed starting in low temps.

This is why I advocate an 8 volt battery in a 6 volt system. With NO tweaking, just put the 8 volt battery in the box, you MIGHT get away with it in Kansas in the wintertime. We farmers try anything to get things working. Its not ideal though. A more balanced system, like 12 volt charging and 12 volt battery is much better. Too many uncles (now in their 90's) and parents trying to hand crank the old AD in the middle of winter because the 6 volt battery wasn't enough to get the kids to school or the husband to work. It was another generation where the Iphone wasn't the order of the day and insulated garages were only a dream of the future. It's a very real issue in some parts of the world. Cant we all just get along? lol

Back in the late 60s and early 70s, I saw many A-D trucks in VA that had 12 volt replacement cables. The shade-tree solution to starting in those "cold" VA winters (6 degrees warmer than Hesston, KS) was an 8v battery. I kept my 6v battery charged because I knew nothing about 6v vs 12v battery cables, etc.

I now live in upstate NY. It gets a little cold here in the winter (7 degrees colder than Hesston, KS - usually a low below 0 around February 1st). With proper battery cables (both leads), clean connections, and a 6v Optima battery, my Suburban starts in Jan/Feb (after sitting without being charged since November). My garage is detached, unheated, and provides excellent winter cold-storage.

I have done this start-up test during the last two winters (7 year old battery, with no battery minder) - just so I know the truck will start in the coldest weeks of the winter.

Sure, a 12 volt conversion provides better cranking (but it is no longer a 6v truck). If a 6v battery does not crank in the cold, there are problems that need to be corrected. An 8v battery will work fine, but if it is needed to reliably start a 6v truck, it is a band-aid covering other inadequacies.

I get along with whatever someone wants to do. But, I only post like this in response to a solution to a problem that would be solved with a properly maintained system (as it was designed for reliable performance).

I completely agree with everything you said. But inject the human factor of using whatever cabling is available, whatever time they have to maintain their vehicles, nowadays, you don't even need to check the tires for 10 years. If you want reliability with the human factor involved, go with higher voltage. If you are an enthusiast like Tim, myself and most others here giving advice, you will be very meticulous about your maintenance. But not necessarily those reading your fine advice. So, balancing everything, if you are still using your truck as a daily driver to work everyday, you would be ill advised to not look into every advantage available.

We are here to help you, no matter if you have a hang-up over keeping everything stock, or want to make sensible changes to preserve your trucks longevity and usefulness.

its only after the temsp drop below 20 is when i get excited and the colder the better. i can and have gone out to my dump and fire it up when its 8 degrees out on six volt battery. im always amazed at how it sounds turning over then firing. if there is no snow then ill go for a ride after it warms up the cab. good grounds, proper to oversizd cables and a good battery are required. im waiting for murphy to let me down but hasnt yet. when he does it will be time for a new battery.

I'd be intested to hear more from folks who don't think a 12 volt conversion is necessary. The reasons I'm considering one are: dim head lights, and in particularly dim stop lights; after the engine & starter were rebuilt, when it sits for a while it takes some time for the gas to get to the carb (a few times I had to charge the battery). What am I missing?

rc - you might be missing proper battery cables, 6V really should have minimum 1 gauge, preferably 0 or 00 [commonly called 1/0 and 2/0] and the connections should be very clean and tight, preferably with good external toothed star washers, make particularly sure you have good grounds, battery to engine and engine to frame and cab

you'll find all of these old trucks lose the gas in the carb when left sitting, but it shouldn't be hard to start with the right technique, tap the pedal once, immediately pull the choke all the way out and hit the starter, with a good battery and cables it should start pretty quick, if you run the battery down cranking, there's something wrong! and of course you could give it a shot of gas directly down the carb after it's sat for more than a day or 2

wimpy cables [modern 12V sizes] and poor connections can be part of the dim light problem too, but there are also brighter bulbs available, and putting in Bosch relays for the headlights can help by providing a more direct path from battery to lights

Bill

Thanks for your thoughts red58. I do have 00 cables, but I don't have the star washers - will give it a try. Maybe I should also check my battery; it's a new one but may have bought a cheap one. How many amps should a good battery be? One last question, can relays be used for the tail lights as well. Again, I appreciate your thoughts - I have plenty of stuff to do to restore the truck (52 Chevy 3100) and don't want to do stuff that doesn't need done. Bob

Use a #81 bulb for the tail light and #1129 for the stop light along with a spritz of white paint inside the housing. You'll be amazed at the amount of light you get. You might need to put a slight bend in the bracket to make both fit. My 6v '38 tail light on the left with my modern pickup 12v tail light on the right. My '38 coupe's TL housing is similar to your truck's. Use a plastic lens instead of glass. The plastic will pass more light.

Someday, maybe with all of you talking about having no problems with 6 volts, maybe I will change my mind. RCBORST tells it like I know it really is. Long cranking because the bowl is empty, 20 or less degrees means FUGGETABOUTIT! When I vividly remember my relatives/parents breaking their backs hand cranking in 20 or less degree weather because the battery was useless, it changes things for you. When I got back to Kansas in 1989 after 10 years in the AF, that December it was 17 below. Im sorry, but if they had a 24 volt solution that made sense, I wouldn't hesitate. Meanwhile, keep up the encouragement. I have several 6 volt AD's and its costing me a fortune purchasing 8 volt batteries every two years to keep them running 8 months out of the year. That is of course after making sure I have good grounds, 00 gauge wiring, new wiring if I am concerned, electrical engineering background, etc etc. Nevermind that my trucks are in 80 degree climate controlled environment all year. There is something You know that I don't. Someday, keep the conversation going, maybe I will get the proper clue.

yeah, what Tiny sez for the tail lights, and consider adding a 3rd brake light higher up, the main problem with the tail lights on the older trucks is they're just physically too small and low - no need for relays on the tail, they don't draw all that much current, but make sure the wiring is all 6V sizes, heavier than for 12V, long wire runs make for extra resistance that cuts the amps delivered - you might also want to get a battery tender if the truck regularly sits unused for long periods

Deve, if you have problems starting a truck that's kept in a living space climate, it's got nothing to do with 6V, and I'd be surprised if a 12V battery would crank well sitting outside in below zero weather, winter in a cold climate takes mitigation even on new vehicles, like a block heater and battery blanket .... if the problem is simply the carb drying out [they're vented, so fuel evaporates over time], learn what it takes to start it under those conditions, GM put manual chokes on these trucks for a reason - failing that, just keep a 12V battery booster in your hot garage and hook'er up after the truck's been sitting for a long time, temporary 12V won't hurt anything but will make that 6V starter dizzy

Bill

I'd recommend ditching the 8V battery for a 6V Optima.

Hey gang, I don't see myself looking to go to a 12 v. Does anyone have a part number for the 6V Optima battery I am reading about ? is it a NAPA product?

Thanks,

joe

the Optima product is an Optima product should be available anyplace that has a good selection of batteries, just ask for an Optima 6V battery

Bill

One thing that always seems to be left out of the 6 to 12 volt conversion is the fact that the 12 volt battery will crank the 6 volt starter so fast that you could probably dump the clutch and drive down the road with the ignition turn off. Maybe qualify for a hybrid vehicle tax break. The starter probably wouldn't last very long. My point is, increased starter speed is what gets these engines started when its cold or your battery terminals aren't fresh, or your points aren't perfect, or your carb is a little dirty. If you converted both the battery AND the starter to 12 volt, I don't think you would have much improvement in starting under the above mentioned conditions. Six volt starters with 6 volt batteries work just fine when everything is clean and fresh and its warm out, but the problem is all of the components degrade with time and leave you in a bad spot whereas a 12 battery with a 6 volt starter may well bail you out. Or you could always park on a hill. Been there, done that.

Deve, Can we agree to disagree about 8 volt batterys? I purchased one, installed it and EVERY body is Happy! Whoops NOT me! After burning out darn near every stop, tail light dash light and what ever light, I had new battery cable made at my local IHC dealer, gave away the 8 Volt battery, replaced with a 6 Volt and have not replaced a fuse or bulb since.

I'm just wondering why this subject doesn't get the same "it's your truck do what you want" that most other modifications discussed receive. I did the switch in 1981 and haven't had a single regret. My reason was cold weather starting and the 12v really spins the 6v starter even below zero, no block heater involved, still original starter. I park outside in all weather year round. Ya it's not original but it gets driven.

Read a few of the many of the other threads dealing with the same subject and you'll find many with that opinion. It's just that some of those who've chosen to participate in this thread are of the opinion it's an unnecessary effort and expense. My '38 is still 6v and starts in cold Kansas at 20 deg and colder when I ask it to. Admittedly I don't ask it often because the oil is so thick when it's that cold. There's a lot of lubrication that depends on splashing, oil being thrown about and plain old gravity drip that is delayed longer than I'm comfortable with when the oil is that cold. It being 6v plays NO role at what temperature I start it up. It doesn't require 00 cables but I do have an Optima battery, 0 cables and clean connections. There are a lot of opinions on the 'bolt and rarely do they all agree. The key is being able to disagree without being disagreeable to quote the PBB (President Before Bush). Those who get their skirts blown up over their heads because someone disagrees with them need to take a chill pill. FWIW I converted my old 55.1 panel to 12v back in the '60s and never looked back. I'm of a different opinion now and would leave it 6v if I were to make that choice today.

Yeah, I feel kinda bad about my outspokenness on this subject. Anyone who enjoys these trucks should always have a smile on their face, and a song in their heart. Its why we do this. If 6 volts works for you, happy trucking.

I often get carried away with these issues. Part of it is that it was my job for a number of years writing technical manuals for communications engineers for the FAA. Then I moved to training manuals for comm technicians. It was gratifying because it was logical and made sense to use the best knowledge we currently have to enhance our air traffic system. So, I speak on these matters from a technical perspective, not from the heart. Since these trucks came with 6 volts, and everyone knows these are mechanical beings with personalities all their own, I often dismiss that concept but I know its more powerful than I give it credit.

Definitely to each their own. Its like rear wheel drive. After front wheel drive came out and was found to be superior on winter roads, people still prefer rear wheel drive. There is no reason other than a mental heartfelt feeling its a nice thing. So, my apologies for anyone I might have offended. I only think in logical terms mostly and its not the most popular way to think. But its ME!

Every restoration I ever do will be governed by logic and what makes technical sense. I will enjoy my trucks immensely, just like you all do.

...one of the things that make the Stovebolt great is all the opinions and information one gets here. (right or wrong) Then its up to us to sift through it and decide if it will help us decide what works best for us individually. To be informed assures a better decision..... and we are also priviledged to change our opinion from time to time