12 volt conversion wireing diagram

Fri Feb 06, 2004 3:11 pm

Does anyone have a wireing diagram using the Nissan, Hitachi alternator?
I have the alternator. The battery and ground connections are self explanitory. But the plug in connector is T shaped and has no markings. Does anyone know what is what with them?

Sat Feb 07, 2004 12:14 am

I did a one wire conversion with the Hitachi alternator. I'll have to go look tomorrow, but from memory, just one of the leads is used as an exciter. I just took out one of the pigtails of the T connector, chunked the rest. Works great. I let you know which lead is used, if you're doing the one wire conversion.


Sat Feb 07, 2004 6:47 am

That should do for me Thanks

Sat Feb 07, 2004 8:30 am

It appears I have the top, or yellow wire run right over to the Batt. wire post for the exciter. The other, black and white wire, I didn't use. I got a lot of info from this forum. Many, many guys have done this. If this doesn't work for you, keep asking. They'll chime in.

Hey Rudi, wouldn't this be a good addition to your web site? A step, by step, 6v to 12v with pictures?

Sat Feb 07, 2004 8:56 am


Yes it would be :idea: Are you volunteering :!: :D :D Hope so :!: That is what we need on the server - any other ideas :?:

Sat Feb 07, 2004 1:06 pm

The top wire (yellow) is for the regulator sense, this should be jumpered to the bat lug. The bottom wire (blue I think) is for the impulse this is to get the aternator to start. It can be wired to an ignition switch with a blocking diode or wired directly to a momentary switch. I used a momentary.


Sat Feb 07, 2004 3:58 pm

I take it then the top of the T connector is the exciter for the stator and the Ts post is for the voltage sensor. HRs exciter the Ts top wire must go through a switch or the alternator will be in constant excitation and will drain the battery when the engine is not running.
Here is a site that has some usefull information.


Here is a site on N series that has a diagram using a GM SI 10 alternator, using a marker lite in the exciter circut. There is a diode available from Ace that plugs right into the alternator and the marker lite is not needed. I have used this on my 48, 8N and it works good. The marker lite or diode is needed to keep the alternator from back feeding the electrical system and having run on after the key switch is turned off.


My 50 cub has a magneto so I will not have to be concerned with run on and I will probably use a momentary switch to start excitation.

Sat Feb 07, 2004 6:15 pm

HRs exciter the Ts top wire must go through a switch or the alternator will be in constant excitation and will drain the battery when the engine is not running.

Well, in a sense. I have the battery switched. I might add that I have a distributor instead of a magneto.

Sun Feb 08, 2004 6:31 pm

I guess the reason I thought this might be a good addition to Rudi's site would be so I could reference it. While I could take some nifty pictures, I'm afraid my commentary would not do it justice. This topic pops up pretty often as new members sign on, so instead of telling them this subject is deep in the archives.....we can just point them to Rudi's place. Just a thought.
Rudi, this spring, I will be splitting the'74 for a new clutch and t.o. bearing. Since this requires a fair amount of disassemble, I'd be happy to document what ever(pics too) you think would be of interest. Sand blasting, priming and painting as well.

Sun Feb 08, 2004 6:45 pm


That would be great and a boon to all those who are going to do the same thing in the next year or so!

Don't worry about the commentary! You will do fine! Writing isn't that difficult, and is a lot easier when you are writing about something you like!