40 amp. alt. question!

[0204bit]

I'm finishing up a 40 amp alt. istallation. The main power wire from the alt. goes to the fuse block right? Where does the other wire from the alt. plug in or attach to? Thanks

 

[BigTom]

Instead of trying to remember or make up an answer, I'm going to give you the spot with the pictures so you can do it.

http://home.insightbb.com/~mmartin36/Disclaimer

If I could remember the quick answer (I think I remember, but I don't want to be wrong), I'd give it to you. Mike's site will tell you the answer you seek. Sorry I couldn't be more help.

You are just about down if you are down to the wires. Good for you!

 

[0204bit]

Thanks Big Tom! Even with those instructions it is unclear to me where the pig tail plug goes that runs with the wire from the alternator. Do you have to remove the plug and where on the fuse block do you attach it or is there a mating plug that comes out of the fuse block? Thanks

 

[juddspaintballs]

I wish I could tell you, but I had help doing my upgrade and Dave took care of the electrical while I overhauled my swingarm and installed fresh oil.

 

[SilverSTreak]

RE:

I'm finishing up a 40 amp alt. installation. The main power wire from the alt. goes to the fuse block right? Where does the other wire from the alt. plug in or attach to? Thanks

The MAIN wire goes to the FUSE (or fusible link if you reused that)

The other connector goes to a connector in the wire harness as shown in the photo below: (click on image for large version showing pointers)



Hope that helps?

 

[BigTom]

Well. I did remember If it hadn't been here now, I'd have gone out and looked.

 

[0204bit]

Thanks for the help. I've got it figured out now!

 

[Martin_b]

Here's the quick answer:

The small wire goes to a switched source of 12 volt power. One way is to connect it to the black wire that used to go to the old VRR. Another way is to look on the left side of the frame there for another connector that also is switched and fused.

However........

The far superior way to connect that wire is to set up a relay taking power directly from the positive terminal of the battery and hooking it up to that. Make the relay triggered by the same wire that you would have otherwise run to the alternator.

The benefits are thus:

The current supplied by any of the stock wires on the ST, goes through a long path up to the switch and back to the fuse block. It includes a bunch of connectors. In time the connections corrode, lowering the volatage available to the alternator. Also, there are voltage drops also because of the long path the current takes and the relatively small size of wire. It works, but only just. And as time goes on, you'll eventually see your alternator output voltagef drop.

I hooked my 40 amper up to the original wire feeding the VRR. I got 14.2 volts with the new alternator. Then, though the years, I saw my voltage drop slowly but steadily. Finally, frustrated with the situation, I analyzed the situation and realized that the magnetic field in the alternator was created by the current going to the small wire at the alternator. Less voltage means a weaker magnetic field which means lower ouput. So I did the rewiring, a simple task, and found I now got 14.4 volts. Up from the 13.6 it had dropped to and up from the original 14.2 as well. Nice.

 

[ThreeWheels]

I think I'll try this out over the winter.

Here's the quick answer:

The small wire goes to a switched source of 12 volt power. One way is to connect it to the black wire that used to go to the old VRR. Another way is to look on the left side of the frame there for another connector that also is switched and fused.

However........

The far superior way to connect that wire is to set up a relay taking power directly from the positive terminal of the battery and hooking it up to that. Make the relay triggered by the same wire that you would have otherwise run to the alternator.

The benefits are thus:

The current supplied by any of the stock wires on the ST, goes through a long path up to the switch and back to the fuse block. It includes a bunch of connectors. In time the connections corrode, lowering the volatage available to the alternator. Also, there are voltage drops also because of the long path the current takes and the relatively small size of wire. It works, but only just. And as time goes on, you'll eventually see your alternator output voltagef drop.

I hooked my 40 amper up to the original wire feeding the VRR. I got 14.2 volts with the new alternator. Then, though the years, I saw my voltage drop slowly but steadily. Finally, frustrated with the situation, I analyzed the situation and realized that the magnetic field in the alternator was created by the current going to the small wire at the alternator. Less voltage means a weaker magnetic field which means lower ouput. So I did the rewiring, a simple task, and found I now got 14.4 volts. Up from the 13.6 it had dropped to and up from the original 14.2 as well. Nice.

I had a similar situation. Over the years, my running voltage had decreased to about 13.4 Volts. I first cut the small wire to the alternator field and, with 12.5 volts at the battery I measured 10.5 volts to the alternator field. I made the modification and with the bike running, I'm getting 14.2 volts.

Here's a picture.