[hotrodcommuter]

1969 Buick special.
I installed one wire alternator from 75 Camaro.
ran it for a few miles
30 amp fuse pops 2 seconds after start up now.
any suggestions?
There’s only one wire going from battery to alternator?
I had the unit swapped out, same problem.

 

[ExcellenceAuto]

Alternator puts out way more than 30 amps. Where is the fuse you speak of?

 

[hotrodcommuter]

I put a 30 amp on the wire to battery, do you think a higher rated fuse is in order?

 

[MGK]

Typically the charge wire (alt to Bat) is not fused, just wire of adequate size to handle the alt output. Load circuits (power going to the car circuits) are protected by either fusible links, resettable breakers, or mega fuses. These would be feeding the Ignition switch and battery side of fuse block.

 

[hotrodcommuter]

But I’ve worked in a one wire alternator, so it is independent,

 

[2old2fast]

Toss the fuse , 10 ga or larger the the bat .
Why are you fusing an alternator ?

 

[75gmck25]

GM used a lot of 30 amp fuses in the wiring back in the time when alternators maxed out at 63 amps or less. Even then the charge wire used a fusible link because the alternator spiked up to higher amperage under load.

If you want overcurrent protection I would buy/find an 8 gauge charge wire with a 12 gauge fusible link. They were common on GM vehicles in the 90’s.

 

[joe_padavano]

No GM car came from the factory with a "one wire" alternator. The first question is, what do you really have?

 

[BogiesAnnex1]

Never saw the point of a one wire alternator, they have trouble exciting themselves in the RPM range where if you’re driving in city traffic you need them to keep the battery and accessories up. The root problem is these things are rated at maximum output which means at some optimal RPM they don’t just put out this power simply because the engine is idling. So if your sitting in stop and go traffic with the stereo blasting and the air-conditioning on high your sucking a lot of power off the battery the alternator isn’t putting back.

Bogie

 

[joe_padavano]

Never saw the point of a one wire alternator, they have trouble exciting themselves in the RPM range where if you’re driving in city traffic you need them to keep the battery and accessories up. The root problem is these things are rated at maximum output which means at some optimal RPM they don’t just put out this power simply because the engine is idling. So if your sitting in stop and go traffic with the stereo blasting and the air-conditioning on high your sucking a lot of power off the battery the alternator isn’t putting back.

Bogie

Amen. Consider that GM, who never missed an opportunity to shave a few pennies off of production costs, never used a one wire alternator in a production car despite the money they could have saved on copper. The one wire was designed for agricultural and construction equipment that operates at a fairly constant RPM, not for passenger cars.

 

[55_327]

Another hit on a one-wire alternator is it has no "sense" wire. That means the alternator regulator measures and maintains output voltage at the alternator and not at a junction block or a "splice" as GM called a merging of wires. That means you could have 14 volts at the alternator, but only 13 volts or less feeding the fuse panel, especially with undersized OE wiring and loose or corroded connectors.

But whichever type alternator you use, below is a good way to wire it and the fuse panel feed. 6 gauge wire and 175 amp fuses are overkill for most applications. In a truck I did a few years ago, I used 8 gauge wire because it was easier the work with, and 100 amp fuses, as recommended by AAW. They also have a newer kit that uses only one fuse and is wired differently.

 

[ernestsaxton]

1969 Buick special.
I installed one wire alternator from 75 Camaro.
ran it for a few miles
30 amp fuse pops 2 seconds after start up now.
any suggestions?
There’s only one wire going from battery to alternator?
I had the unit swapped out, same problem.

ground the alternator directly to fire wall using the extra bolt hold in the back of unit it might fix the problem

 

[ernestsaxton]

ground the alternator directly to fire wall using the extra bolt hold in the back of unit it might fix the problem

bolt hole its a low cost solution to try

 

[williamallen21]

Read lots of posts and uTube videos about these related problems with one wire applications when I first got my 72 C10 with twin electric fans and updated lighting, radio with heavy draw not originally designed for. Had only an 80 amp alty and just couldn't keep up. Batt kept going flat so I looked into updating alty to an 150 to 200 +'amp unit to keep up. Many videos warned about too small of existing wiring (10ga) going back to battery and others warned about insufficient grounding wiring. I updated both and used a wiring setup like previous posts from '55-327' shows. Added another 10 GA wire back to battery (so now has two 10 GA wires parallel) with 100A megafuses connected to battery. Also added ground wires alty to block, block to cab with woven ground straps. I used a Tough Stuff 220 amp one wire alty. I have found it to be very efficient, self excites itself within driving a block or so on first drive of the day and then on subsequent restarts that day self excites instantly. At first the reports of slow self excitation worried me, but have not found it to be real issue with this brand at least. The days of a flat battery are over. Volt meter consistently reads 14.7 before starting and 13.5 with A/C on high fan blowing speeds.

 

[2old2fast]

Like the previous poster said , my one wire alternator has never given me any problem . IMO ,most of these " problems " are due to faulty , insufficient , poorly installed wiring , too much aftermarket junk added to what's really needed & an otherwise total misunderstanding of auto electric systems in general ! If you don't have enough power to run your vehicles needs at stoplights/ in traffic , etc , IMO ,you're suffering from an undersize / failing battery &/or undersize wiring & switches to carry the load , inadequate grounds are often an issue as well . Again , IMO , if your 1wire conversion alternator does not excite immediately when the engine reaches 1000 rpm , there's something amiss w/ the self exciting regulator . The other , most famous charging problem of all is still a loose/ slipping belt .