generator vs. alternator

Mon Aug 06, 2007 12:12 am

So I keep going back and forth: asthetics vs. cost. However, I know nothing about generators. I'm finishing a 12v conversion and I can use any and all opinions (charging, durability,etc.) between the two to help my decision.

Mon Aug 06, 2007 6:02 am

The difference is the charging output (amps). The generators are around 15 amps while the alternators can go from 70amps to 100amps. If your going to add more lighting the alternator would be a good move.

The problem is to keep it all orginal or not, thats my problem too. Anytine i change something over i save the orginal stuff i took off to change it back if i ever wanted too.

I been using a GM 70 amp alternator(older) with the high output 90 amp kit from J.C. Whitney on my power supply that i fabricated for my camp in VT. Its run by a 5hp gas engine with batteries but thats another story/post. The wiring is simple I ran the exceiter wire to a toggle switch, the other wire to a bulb which gets connected to the other terminal and the 12v power wire to the battery thru an amp meter. When i turn the switch on the bulb lights and when its started the bulb goes out telling me its charging plus the amp meter shows how much charge i'm getting. I have had very low batteries that i used two D cell flashlite batteries to exceite the alternator to get her charging. It takes a little power to get things running.

Mon Aug 06, 2007 7:10 am

Any 12V at all is not "original" until you get into the mid 1960s, so I personally wouldn't worry about originality in a 12V conversion.

If this is to be a working tractor, an alternator is the only choice for reliability and maintainability. With generators, you've either just fixed it or are just about to fix it, IMHO.

For originality, stay with 6V. A well-maintained 6V system is more than adequate.

Mon Aug 06, 2007 9:09 am

have a generator on my Oliver 66 that is a 6 volt unit. only about 57 years old and still working

Mon Aug 06, 2007 9:24 am

My '52 Cub is converted to 12 volts. I have been very satisfied with the process (Hitachi alternator) and the results. Since then, I have been reading this board and realize that the problems I "fixed" by the conversion could probably have been done with a few maintenance chores. I do use my Cub regularly, so I guess it is a working machine, and the 12v is handy. Dang, that doesn't help your quandry at all!

Mon Aug 06, 2007 9:52 am


Ellie is a working tractor. The only reason I can keep my Cubs is that they do the chores... and pretty much all of them now or in the very near future.

Ellie is a 48 with a Key Switch, Magneto System with Battery, Starter and Electrical Package. She is a pleasure to start and very easy. The 6 volt system is really simple to work on and clean up. And because I have a Magneto.. if I have an electrical breakdown, all I have to do is disconnect the battery and a couple other terminals (I forget which at the moment -- CRS yup.. got that too :!: :roll: ), and I can start her up with the crank. For a guy with a split and rewired rib cage.. even this is easily doable.... not hard at all.

So, my concern is not really about aesthetics or even cost, as the cost to convert a complete 6 volt system is substantially more than the other option. That option is to maintain your current 6 volt system. I am an electrical dummy.. yup.. you heard it right.. I am and electrical dummy. And with BD, Ron, Cecil's and a few others, even I can do this work. So for anyone who can tell the difference between a Phillips, a Standard and a Robertson (square drive), this is basic easy stuff. Also there is a section on the Manual Server specifically on Generator's. I found the info I needed on YTMag and with their permission that info is used on the server so it might help others understand it. Hopefully that will help.

So my question I guess becomes.. why do you want/need to convert? IS something missing? IF not, Fix the current system and you probably will be happy with that. Don't band-aid it... fix it :idea: :!:

Like the guy in the suit for the Orange company ING says -- It's your money !

Mon Aug 06, 2007 10:46 am

With regard to the amperage of alternators used for conversion, one wonders what advantage is offered by those units with very high output. My converted Cub has a 55 amp unit, the only Delco the local salvage yard had on the day I bought it. I would have preferred a 37 amp unit. Both are the same physical dimensions. I do use mine to jump start and boost the battery as necessary on some larger Diesels. The 55 amp unit will produce a noticeable load on the Cub engine. Recharging the Cub battery after a start is very rapid. A larger unit would be more so. Rapid recharge is not good for batteries, but sitting with only partial charge is worse. The belt driving the alternator has limitations, too.

Mon Aug 06, 2007 11:12 am

I have 2 Cubs with alternators, one is a Hitachi conversion the other original. They both work well.
I also have 2 tractors with generators, both have served well without any problems. My only complaint is the generator with the cutout, if you’re not careful you can easily fry the battery if the tractor is worked for long periods with the 4 position switch left in the high charge position. Anymore, I never use the high charge during the day.

Mon Aug 06, 2007 12:22 pm

My experience with 6 volt systems on the older chevy/gmc trucks was that i found them very acceptable if you kept the engines tuned, the starter & generator in good condition plus having a good 6v battery was the key to starting ion cold weather. But we must remember that using a lighter engine oil makes a big difference too. While the old 6's turned over very slow they did start everytime. Now whats the difference between then and now? The older stuff is neglected and not kept tuned like they once were.

I did see a 6v running / 12v starting battery that can be added on somewhere.

Mon Aug 06, 2007 1:50 pm

Generators, especially 6 volt generators, seem to get a bad rap everywhere. :cry: I prefer originality. That said, if done right a Cub's alternator conversion is hidden, so that's not such a big deal for me. I hate seeing an A, B, or similar IH tractor with a sloppy alternator conversion hanging off the side..... :evil:

I firmly believe most alternator conversions are not necessary. Using clean, bright, tight connections, the proper sized battery cables, properly maitaining the battery, and keeping the engine properly tuned can be cheaper than an alternator conversion......

FWIW my 6v. Super A spins right over nicely....


Tue Aug 07, 2007 2:59 pm

On my working 66 Loboy I replaced the gen which was shot with a GM alternator. This tractor was originally 12 volt. It was a very simple install, I just had to make a lower bracket, the upper bracket and belt worked fine. I did use a 2 wire setup because I found that my single wire hookup wasnt very reliable. Since I'm an auto mechanic by trade, I replaced the ammeter with a volt guage, because thats just what I'm used to seeing. This tractor sits outside at my cabin covered with a tarp and it always starts right up and starts to charge instantly and reliably no matter how cold or how long its been sitting. I also have a 57 that is all original and will stay that way no matter how erratic the ammeter reads. Just depends on what you want your tractor for. I like both of mine equally, they just each have a different purpose.

Dave F