I'm planning to buy one of these as this is what everyone here has mentioned for 12 volts conversions on tractors. I have a tractor with a dead alternator so I'm going to buy one of these. I see two different amp rating listed - one at 63 amps and one at 100 amps. I'm just putting it on a letter series tractor so seems like the lower amp rating would be good. I don't know what the current alternator was rated for. Lights, starter and ignition is all the electrical on the tractor. Thought I'd ask before buying.

Shoud be a picture here of GM factory service manual with fusible link. Alternator is called generator.The year is 1985. The remote sense wire has fusible link also.

A couple comments:

1 - Buy the smallest output you can find - 37 amp if you can find one. The lower the output od the alternator the LESS RPM is required to "turn on" the alternator at startup - critical for a low RPM tractor engine. And 37 amps is more than sufficient for typical tractor use.

2 - Do not fuse the alternator output! GM did not fuse the output in vehicles equipped with the 10SI. Reason: By design the 10SI alternator is inherently current limited. Even with a shorted internal regulator it cannot exceed its design output amps and overload the wiring. Also should the fuse blow (or the output wire disconnected....) while the alternator is operating it lets the smoke out and ruins the alternator. (I learned this the hard way...!)

Hi Bob,

Dunno if I agree with this, at all.

You should fuse the system, to not do so is risking a fire hazard.

Regarding rpm, I wouldn't buy a self-exciting 1 wire alternator.

If really worried about low rpm and have a self-exciting alternator, switch to a smaller pulley.

I too say no fuse and there is not a single car/truck/tractor that uses a fuse in the alternator circuit

Agree about problems with self-exciting alternators, and to use a smaller pulley to spin the alternator faster.

However I know of NO manufacturer that uses a fuse (or a fusible link) in their OEM vehicle alternator output wiring (I've yet to encounter one in my nearly 50 years of wrenching on cars, trucks, tractors and boats). So I stand by my recommendation to not use a fuse...

Hi Bob,

I can think of several scenarios where having protection in the system would save the system from wires melting/fires.

For me, the added protection of a cheap fusible link, in case a dead short occurs, is what I am doing.

To each his own.

Why fuse the wire from the Alt to bat. It would need to be a pretty big fuse like in the 35-100 amp range depending on the amp rating of the alternator. If smaller fuse is used it could blow from the load demanded by the electrical system if lights or such was added beyond what came on it. The it would not charge at all till the fuse was changed.

I agree the fuse should be set based on load demands/wiring but to not fuse is, in my opinion, a hazard.

I am sure many people have never had an issue not fusing things, but in my opinion it is not worth the risk and if you load demand exceeds the fuse, then you have an issue you need to resolve, not simply decide not to fuse.

I like using the GM one wire. I have been buying them from DB Electrical.

https://www.dbelectrical.com/products/alternator-for-tractor-generator-1-wire-w-1-2-inch-pulley-john-deere-case.html

Get one made for a 1980 Chevy pickup no power any thing no A/c and if you can do so at O'Reilly's it will have a life time warranty. That year they used a 35amp alternator which is more then you need and cost is around $50

recommendations, made to me, is hitachi, because it works at lower r p ms

With regular IH lights a 37 amp works for me. Like Jim posted the 63 ort to do it.

The 63 amp will power your tractor uless you have a ligth bar drawing 40 amps. Tell us what tractor to assist us. Jim

Jim, it is rare when you miss details, he said a letter series Farmall I don’t think he needs to differentiate for electrical load, any of those would be similar and I agree a 37 amp would be fine. They ran many late 60’s GM products with a full compliment of head, tail and clearance lights, a heater blower and electric wipers.

Well some, like an H or super H are easier to fit with a Hitachi, or if they intend to use it for a light show. So were good to go. Jim

My 2 cents...

I just went through this, this weekend.

Picked up the 10si first and was not happy with hos tight the fit was and what little adjustment I would have had, so I swapped it for an older camry/seleca alternator - basically same size as Hitachi and am happy I did.

Was a breeze to install and because of the smaller size, made bracketing with existing belt easy.

Highly recommended.

I would add, the Hitachi road would have been easier to wire as it is the same as the 10si, but the 3 wire on the camry/celica alternator is pretty simple as well, seems the only difference is that a light ground terminal is on the camry alternator.

I am gonna post my drawing of the wiring for this camry alternator to seek input on if I have everything correct, including add-on inline fuses - which I included because I think they smart (the 10si wiring that is everywhere on the internet doesn't seem to include any inline fuses, which I find odd)...

ChampagneNBeer, Nothing wrong with a fuse or a fusible link that GM used, Dorman part #85621.Link can be located next to starter solenoid where battery + cable attaches. This is the point where electrical would feed from. Voltage remote sense wire also attaches here and NOT looped around to battery + on alternator.

Hi Duner Wi,

I agree completely.

Not sure why the diagrams online and this site show jumping the sense wire near the alternator battery output wire - this seems inherently wrong to me, as well as not including fuses/fusible links.

ChampagneNBeer, This tells about remote sense and importance of using it.
Alternator will charge with out proper hook up but not as good as it is capable of. I like the faster chargeing and longer battery life. http://www.delcoremy.com/alternators/alternator-features/remote-sense

Did you read my input below discussing link belts that can be put on without removing the big belt. Jim