Charging System Upgrade Explained

Discussion in 'Mechanics Garage' started by Chris71Mach1, Aug 21, 2008.

  1. Paul47

    Paul47 New Member

    Joined:
    Jul 13, 2009
    Messages:
    84
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    NW Wyoming
    A couple of other things. If a fan is not used, it's probably a good idea to ensure the air flow to the r/r is good. I removed the fuel pump relay which hangs just in front of the r/r, and just let it hang on its wire, next to the fuel pump (it's very light). At the back of the r/r is a flange coming up from the plastic fender which might slow airflow. I cut this flange off so air flows more easily to what is probably a low pressure area under the fender. It's possible some dirt may come up through this larger hole; in that case I'll just staple a little flap underneath to cover the hole from dirt flung from the wheel, while still leaving it open enough for air flow.

    I still haven't put a fan on. If I lived in a hot area with a lot of city driving I certainly would, because this means high temps, lots of stoplight with no air flow, and higher rpms at lower speeds due to lots of low gear riding. I don't have any of that where I live.

    I had one other idea about this. The manual says the alternator puts out 350 watts at 5000 rpm, for a VFR700. (No wonder things get fried!) That amount could be needed if you hang a lot of electrical equipment on the bike, but if you don't then that poor little r/r might have to dissipate 150 or 200 watts. I was thinking it might be possible to derate the alternator if you don't have a lot of extra equipment, by putting power resistors between each of the 3 phases and ground. For example, 350 watts means about 120 watts per phase. Say you wanted to derate that to 100 watts. That means the power resistor has to consume 20 watts. Since P=V**2/R (that is, voltage squared over resistance), and we can guess about 50 volts, that would be a resistance of 2500/20 or 125 ohms, just for ballpark. I looked at Fry's electronics and found 25 watt resistors at 100 and 150 ohms for a dollar each. Anyway, the point is that if you shunt some fraction of the alternator output to ground before it gets to the r/r, then the r/r doesn't have to handle that fraction and it runs cooler. I haven't played with this yet but it will probably be on the agenda this winter.

    Another option is just getting a larger r/r from a current bike and adapting it to our bikes. They all pretty much have the same job to do - rectification and shunt regulating...
     
  2. yclept1132

    yclept1132 New Member

    Joined:
    Sep 29, 2010
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    I realize this thread is old, but just had this problem myself and am going through and upgrading the wiring and came across a question I had. My wiring to the R/R has the three yellow wires from the stator, and then only one red line and one green line rather than the two of each show in the diagram. Because I only have one live red wire rather than two, should I be using a 20A inline fuse rather than 10A?
     
  3. Chris71Mach1

    Chris71Mach1 New Member

    Country:
    United States
    Joined:
    Dec 29, 2007
    Messages:
    493
    Likes Received:
    1
    Trophy Points:
    33
    Location:
    Grand Prairie, Texas, United States
    Map
    yclept1132: what year model is your bike? If it is one of these early VFR's, then something has been drastically changed with your charging system already. As for the fusing of this line, I'd probably stick with a 10A fuse, but go ahead and keep a close eye on it for the first few months of regular riding just to make sure it doesn't get or anything. If it does, I'd step up to a 15A and work from there in an incremental manner.
     
  4. yclept1132

    yclept1132 New Member

    Joined:
    Sep 29, 2010
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    It's a '96. Did they change the wiring set-up through the years? Just curious because when I took everything apart, it looked like the stock wiring harness, connectors, etc. It doesn't even look like there was more than just the one ground wire and one hot wire. The bike came with extensive documentation from the PO on all the work done on the bike and nothing mentions an upgraded wiring harness.
     
  5. tinkerinWstuff

    tinkerinWstuff Administrator Staff Member

    Country:
    United States
    Joined:
    Oct 5, 2009
    Messages:
    7,812
    Likes Received:
    86
    Trophy Points:
    78
    Location:
    Colorado Front Range
    Map
    3rd gen, and probably 4th gen, only had 1 red and 1 green.
     
  6. Onomea

    Onomea New Member

    Joined:
    Oct 14, 2011
    Messages:
    83
    Likes Received:
    1
    Trophy Points:
    0
    Location:
    Hawaii
    Great Post. Will be using the info on my"87 VFR700F2. Found burnt connector between
    Stator and new finned R/R. Will be soldering the three yellow wires and bypassing the
    connector altogether. Corrosion and heat marks on inside of connector on two of three
    spade connections. Third spade connector shiny and unburned.
    After coming back from my first longer ride(about 250 miles) I had no problems on the ride.
    I took off the left fairing to adjust the shock/spring preload and notice the burn marks on
    the inside of the connector. The outside was not melted at all, the inside was a black
    corroded mess on the two side by side spades. I feel lucky I caught it before it got worse.
    Wires coming out of the new R/R were fine with no sign of problems. Maybe the PO did not
    get it to the higher RPMs, so the AMP output did not get that high? I will be checking the
    resistance and countinuity of the stator coupler terminals to be sure. At least the PO gave
    me the FSM along with the bike. I guess he wasn't kidding when he said "you'll need this":(
     
    Chris71Mach1 likes this.
  7. How2

    How2 New Member

    Country:
    United States
    Joined:
    Mar 16, 2008
    Messages:
    35
    Likes Received:
    1
    Trophy Points:
    8
    Habitual Fried RR

    Super.

    Took me forever to figure this one out. I was lucky Electrosport replaced all those RRs for free.



     
    Chris71Mach1 likes this.
  8. Chris71Mach1

    Chris71Mach1 New Member

    Country:
    United States
    Joined:
    Dec 29, 2007
    Messages:
    493
    Likes Received:
    1
    Trophy Points:
    33
    Location:
    Grand Prairie, Texas, United States
    Map
    Gratuitous bump for one old-ass thread! Maybe some of the newer VFR guys can benefit from this one getting unearthed!
     
    OOTV likes this.
  9. mello dude

    mello dude Member

    Country:
    United States
    Joined:
    Jan 3, 2006
    Messages:
    3,888
    Likes Received:
    246
    Trophy Points:
    93
    Location:
    Southwest Ohio
    Map
    I dont think I would wire any bikes like the first post..........
     
  10. pontiac_banshee

    pontiac_banshee New Member

    Country:
    United States
    Joined:
    Jul 3, 2007
    Messages:
    124
    Likes Received:
    0
    Trophy Points:
    18
    Couldn't find my old post but this worked for me perfectly and have never had the problem after.
     

    Attached Files:

    • 1a.jpg
      1a.jpg
      File size:
      68.9 KB
      Views:
      10
    • 1b.jpg
      1b.jpg
      File size:
      53.7 KB
      Views:
      11
    • 1c.jpg
      1c.jpg
      File size:
      59.9 KB
      Views:
      11
    • 1d.jpg
      1d.jpg
      File size:
      59.8 KB
      Views:
      11
    • 1e.jpg
      1e.jpg
      File size:
      56.7 KB
      Views:
      10
    • 1f.jpg
      1f.jpg
      File size:
      56.6 KB
      Views:
      11
    • 1h.jpg
      1h.jpg
      File size:
      64.7 KB
      Views:
      11
    • 1i.jpg
      1i.jpg
      File size:
      50.5 KB
      Views:
      10
    • 1k.jpg
      1k.jpg
      File size:
      47.7 KB
      Views:
      11
  11. thx1138

    thx1138 New Member

    Country:
    Australia
    Joined:
    Jun 26, 2011
    Messages:
    961
    Likes Received:
    35
    Trophy Points:
    28
    Location:
    Perth
    Map
    Keeping connectors clean and tight seems to help too.
     
Related Topics

Share This Page