From the Steiner Tech Support line: 6 Volt to 12 Volt Conversion FAQs
Here are some of the most frequent questions we get about 12 volt conversions here at Steiner Tractor Parts. If you’re thinking about making the switch, here are some good tips:
- Why convert from a 6 volt to a 12 volt system? There are a few advantages to a 12 volt system – tractors that operate on 12 volts start faster and have brighter headlights. A 12 volt battery lasts longer than a 6 volt, and you can jump-start a 12 volt tractor with an ordinary vehicle. Switching to an alternator eliminates the need for a generator and voltage regulator, giving you a more reliable charging system.
- Is it a difficult project? Making the conversion isn’t incredibly difficult, but it’s not a project for a beginner, either. I would rate it as a moderate difficulty. In addition to basic mechanical skills, you also need to know the basics of electrical wiring. If you have the tools and knowledge to change a light fixture in your home (including stripping wires and using stake-ons properly), you’re ready.
- What parts do I need? A standard conversion will require an alternator, alternator bracket, battery, coil, wiring harness, and amp gauge. Replace the existing generator and voltage regulator with the alternator, and swap out the old battery, coil, wiring harness, and amp gauge with the new.
- When doing a 12 volt conversion, do I need a 12 volt starter? In my opinion, no. While some starter shops will sell you a “specially wound 12 volt starter” in my opinion there’s no reason or a big enough difference to warrant this expense. Your original (or replacement) 6 volt starter will function well on a 12 volt system.
- Do I have to change the wiring? Yes. Your old wiring will be set up for a field, an armature, voltage regulator, etc. Using these existing wires could be a fire hazard. Replace your wiring harness with a new one specific to your tractor to have a cleaner look and safer operation.
- Do I need to change the coil? Yes. The 12 volt coil upgrade is very important. I’ve seen some people try to place a resistor in front of their 6 volt coil–not a good idea. The resistor won’t suffice.
- When I do the 12 volt conversion, do I keep the voltage regulator? No. The voltage regulator needs to be removed when putting an alternator on.
- Can I just install an 8 volt battery on my 6 volt system? Yes you can. No changes are required. Many people choose this option.
Do you have videos available? Yes I do! If you are converting a Farmall tractor, you’re in luck! Here’s a link to a video I made on a Farmall tractor. Even though the demonstration model is a Farmall, though, the basic techniques are similar across all makes and models. If you’re looking for help on a different tractor, give a shout in the comments! I’m always happy to hear video ideas.
Barney Stephens says
I,m converting my allis chalmers tractor model ca to 12 volts. Is there a conversion wiring diagram for this model tractor? Is there one on line? If there is how do I get to it to copy the diagram
John Bemiss says
My John Deere model 40 was converted to 12 volts, The headlights were never converted which I did. Can these be wired into the existing switch for the lights
Suzette Thomas says
Yes the switch should work fine, but if you haven’t already don’t forget to replace your bulbs to 12 volt.
maynard sheaff says
Your tutorial is well thought out,and spot on if but for one piece of advice…when doing the conversion,your new 12 volt system will indeed engage the 6 volt starter,however when you start to break the nose cone on the starter,and it will break….due to the extra volts sent to the starter.You have several options: new 12 volt starter,keep replacement nose cones on hand,or what I did was braise the cone back together,and made a brass bushing with an 1/8th inch flange for the pinion gear to hit…this bushing acts as a shock absorber…It was easy enough,but I have a machine shop,so it was 15 mins…but one could find a shop to make it…Ever since I made that bushing I’ve had no issues,5 yrss ago…..So,yes one does need to address the starter.
Don B says
Im getting ready to try and convert my JD 40 C to 12 volts for the 2nd time. First time around I cooked the alternator off of a 1976 GMC 350. I changed the coil to the NAPA one recommended switched to 12 volt battery negative ground wired the 10 ga wire from Batt lead on 10si single wire alternator to amp meter, this time Im using a volt meter, but Im not clear on the ignition wires to the coil. Does the ignition wire hook to the negative side of the coil? and on the 10SI alternator there is a plug along side of the alternator number 1 and 2 it looks as though 1 is hooked to Batt on Alternator with 10 ga wire and 2 goes to coil BUT this is a hook up using a ballast resister. Is this hook up the same without the resister?
Bob Kellogg says
My Ford 641 had a 6vdc starter with positive ground. When I converted from 6 to 12 vdc a decade ago it also resulted in converting the polarity, so why doesn’t the starter turn backwards if the polarity is reversed? My new 12VDC system has worked flawlessly.
Lisa Warren says
The design of the starter only allows one way operation – polarity doesn’t affect the rotation.
Bob Kellogg says
Wow.OK and thanks for the reply. That’s certainly my observation but I didn’t know DC motors could be “tricked” into ignoring polarity.
Harold Smith says
I need wiring diagram for an super A converting to 1 wire altanator .
Suzette Thomas says
Harold we carry the I&T Shop Service Manual which tells you how to take a tractor apart, how to fix it and how to put it back together again. I added the link below for your brand and model. Good luck on your project.
https://www.steinertractor.com/IH8-I—T-Shop-Service-Manual
Jeffrey Jordan says
W2077 State Hwy 29
Jeffrey Jordan says
I,m converting my allis chalmers tractor model B 6 volts to 12 volts. Is there a conversion wiring diagram for this model tractor? Is there one on line? If there is how do I get to it to copy the diagram
joe habbart says
Hello everyone. I have a 1947 jd M, 6 volt positive ground. Built many roads and bridges and so ugly, it’s theft proof. That being said, I’d put a new 6 volt battery in it every 3 or 4 years.
Here’s the funny part. I’d charge it on SLOW trickle charge for a FEW hrs, NOT overnight, every few weeks. NO charging system, a house light switch for ignition and it has worked perfectly for 23 years now. Someone ‘borrowed’ my charger when I wasn’t looking and returned it and hooked it up BACKwards. Smoked that 80$ battery. so anyway, I want to use a 12 volt battery, negative ground and not concerned with regulators, alternators etc etc altho I use it every day on the farm….so? 12 volt coil? distributor condenser? Starter will spin the correct direction with reversed polarity? so here we go, cheap 12 volt battery that can be jumped if necessary, and 12 volt coil? anything else? I’m old and disabled so ez is best for me. Thanks
doc joe says
Hi, My 1947 jd ‘m’, has been unning perfectly on 6 volts. NO charging system, I just put it on the charger on low for an hour or 2 once a month. Been Great for years. Battery is finally giving up so thinking about simple 12 volt setup, NO alt,, maybe just like it’s been working all these years. Maybe a 12v coil? condensor in dostributor? anything else? hanks
Dale Cruickshank says
I just got 47 ford 8n the prev.owner started a 12v conversion! No brackets for alterna. Old wires cut or cracking n short. I’m in search of a diy video or a wiring diagram that has it laid out easier than the shop manual of the 6v original set up. I’d like to NOT CUT ? Gadge areas out to fit new aftermarket ones in . I want original look ! Just 12v upgrade
ST says
Dale we have a 6-12 volt conversion video that may help. I added the link below. Good luck on your project.
6 to 12 Volt Conversion
Roger Zick says
I have a 51 Ford 8N. It is 6volt setup. It is hard to start. I want to change it to 12 volt. What parts do I need to replace and what parts can be used? Do you have a wiring diagram for it? Thanks
Lisa Warren says
Hi Roger – is this a front mount or side mount distributor? I look forward to hearing back from you so I can select the correct kit for you.