One wire alternator

[SilverFJ60]

As part of an engine swap (Gen 1 small block Chevy 305), the new alternator (CVF 100 amp, one wire) has only one power wire connector and one case ground connector. The stock wiring has 2 white wires that went to the power connector plus a yellow wire and a black/yellow wire.
Two Questions:
> Another post says to connect the white wires to the power connector and leave off the yellow and black/yellow wires. Is this right? And, will the alternator light on the dashboard still work properly?
> Will the higher amperage of the new alternator blow the fusible link in the white wire circuit?

 

[CruiserTrash]

As part of an engine swap (Gen 1 small block Chevy 305), the new alternator (CVF 100 amp, one wire) has only one power wire connector and one case ground connector. The stock wiring has 2 white wires that went to the power connector plus a yellow wire and a black/yellow wire.
Two Questions:
> Another post says to connect the white wires to the power connector and leave off the yellow and black/yellow wires. Is this right? And, will the alternator light on the dashboard still work properly?
> Will the higher amperage of the new alternator blow the fusible link in the white wire circuit?

I’m not an expert in one-wire alternators so I can’t answer the first question. The answer to the second question is definitely maybe, under the right circumstances, which according to Murphy’s Law will happen exactly at the worst time and leave you stranded. Maybe not though - but you wouldn’t want to find out, would you? If it doesn’t blow, the fusible link wire might get pretty hot. It would definitely take some load to clip the link wire, perhaps if you’re running a bunch of electrical (cold rainy day, both heaters blowing, headlights on, wipers going, etc) or if the battery is low on a cold start.

Shameless plug, but I sell two versions of a fusible link replacement kit for the 60 Series. It’s a pre-wired fuse panel and bracket so you slap that thing in the engine bay, connect the wires, and go. Not only can you stop worrying about tracking down discontinued fusible links if yours blows, but you can customize the fuse values to suit your needs as well. As shipped, I size the fuses for stock vehicles but the end user can change the alternator fuse if need be. I recommend leaving the other fuses alone, for safety, since I did a lot of math to arrive safe fuse values for those. Link in my signature if you’re interested.

 

[SilverFJ60]

Thanks. I'll check it out.

 

[Eurasiaoverland]

You will not have a dashboard warning light. The white wires going to the main pole of the factory alternator, and the thick sense wire all connect to the battery. But, given you have uprated the alternator, it might be a good idea to uprate the wires back to the battery. The alternator will also need a good ground as it will be permanently wired to the battery (unswitched) so any constant draw will flatten the battery over time.

Also, as there is no exciter wire, the one wire alternator only starts charging once it reaches a certain RPM so you might find it does not charge if you start the engine and leave it idling.

Seems like a lot of disadvantages for no real gain.

 

[yotadude520]

When I did my LS swap I dead headed the two alternator wires with the plug on it, then I extended the white wires to the fusible link that meets up with the LS alternator.

Being that this is a higher output alternator I would definitely buy @CruiserTrash's kit and then upgrade the fuse that he uses to a 125 amp. You can see how I wired my LS alternator with his setup here

Stumbling my way through an LS Swap - https://forum.ih8mud.com/threads/stumbling-my-way-through-an-ls-swap.1342975/page-4#post-15720026

I've had no issues with the charging setup running it this way, and the ampmeter on the dash still works.

 

[SilverFJ60]

Thanks for all the great advice. I'll add an 8 awg wire from the alternator through a 100 Amp breaker to the battery to run parallel with the original white wires. With any luck, sharing the load will prevent blowing the fusible link during high load events. If that doesn't work , I'll check out the kit mentioned.

 

[CruiserTrash]

Thanks for all the great advice. I'll add an 8 awg wire from the alternator through a 100 Amp breaker to the battery to run parallel with the original white wires. With any luck, sharing the load will prevent blowing the fusible link during high load events. If that doesn't work , I'll check out the kit mentioned.

To run the wires in parallel, you'll need to figure out the resistance through each wire and how they're sharing any current. With one wire at 8awg and another at (maybe) the metric equivalent of 10awg, they aren't going to be sharing the load equally and they'll each need to be fused separately - and each at a lower value than the total current that the alternator can supply. What you're doing is creating a current divider network. You'll need to run your measurements through Kirchoff's Law to arrive at safe fuse values.