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    need relay suggestions

    My main ignition switch is dropping a couple volts. I wired in a Bosch 30 amp 12 V automotive relay, specced for constant use (fog lights etc.). Twice now it's worked fine in my garage, fine when revving the engine on the stand, and 3 blocks of riding and it dies. The first relay I took apart and the coil wire had broken just between the terminal and the coil. I'm thinking I need something built a bit more tough.

    For what it's worth, the wire from the ignition switch and a battery ground
    go to the trigger side, a fused 12v+ lead from the battery and a wire to the fuse box go to the switched side.

    #2
    Where are you stashing the relay? Use a piece of foam insulation might help.

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      #3
      Originally posted by Billy Ricks View Post
      Where are you stashing the relay? Use a piece of foam insulation might help.
      I hung it on a zip tie next to the battery box. I figured that should have insulated it from the vibes well enough. I could glue it to some foam I suppose.

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        #4
        Still having this problem? It's a little odd that it would happen twice. I would be looking for shorts somewhere and double check how you did the wiring.

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          #5
          Paul,

          I got one of those cheap $3.99 40 amp units from the zone and have bounced my front off the pavement a few times; it seems to do just fine. Did I mention that it is rigid mounted to the frame?

          Someone on here suggested TYCO relays.

          I did leave the original wiring unhacked, so that if the relay did fail, I can plug the coils back in to the stock harness.

          I went from a 1.5V drop to a .05 drop. I just ordered NGK plug boots because they measured out over 1MM ohms. OUCH

          Comment


            #6
            Originally posted by p_s View Post
            My main ignition switch is dropping a couple volts. I wired in a Bosch 30 amp 12 V automotive relay, specced for constant use (fog lights etc.). Twice now it's worked fine in my garage, fine when revving the engine on the stand, and 3 blocks of riding and it dies. The first relay I took apart and the coil wire had broken just between the terminal and the coil. I'm thinking I need something built a bit more tough.

            For what it's worth, the wire from the ignition switch and a battery ground
            go to the trigger side, a fused 12v+ lead from the battery and a wire to the fuse box go to the switched side.
            Trigger is right,

            The heavier wire that stems from the relay (switch on), split off and go directly to the coils, not back to the fuse box.http://www.mediafire.com/?zxfm2wildzv
            Last edited by Guest; 05-01-2008, 03:37 PM.

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              #7
              I created a "relay farm" under the right side cover using four 275-001 automotive relays from Radio Shack. 12V, 40A, -40F to +257F. $6.99 each. Mounted to a steel L-bracket screwed to the battery case. One relay for the high beam, one for the low beam, one for the coils, and one for everything else. Been running it for several hundred miles now. No problems of any kind. But have pre-made jumper wires that I can use to bypass the relays just in case.

              Comment


                #8
                Originally posted by 82Shafty View Post
                Trigger is right,

                The heavier wire that stems from the relay (switch on), split off and go directly to the coils, not back to the fuse box.http://www.mediafire.com/?zxfm2wildzv
                I'm not doing the coil relay. I'm just bypassing the main ignition switch, since that's the problem. Mainly it was because occasionally the starter relay doesn't get enough power to fire. The second reason was because my headlight was a little dim at idle especially if the brake light or turn signals were on. Most of the drop was through the main switch--bypassing it solved these problems until the relay burns out.

                Maybe I'll try another brand and if not just give up. Leaving on my big trip early Saturday and this isn't a show-stopper at all.

                I can't really see how a short can cause this to happen. Something has to cause there to be much more than 12V across the trigger, or it just can't take the vibes. In the garage the voltage on the trigger side never exceeds 13V or so. I'm baffled.

                Comment


                  #9
                  If you say relay can't take the vibes, when you have it in the garage, beat the sh*t out of the relay while it's running to see if its the relay.

                  I can't see what would cause the mini coil to burn out in the relay either.

                  I guess it was a good thing I got the 40 amp unit.

                  Worse case scenario, just mount a 30 amp toggle switch or carry one as a back up; a mini fuse would ensure electrical protection.

                  Comment


                    #10
                    The 40 amp rating refers to the switched circuit in the relay. The trigger circuit is rated for much less. I would guess they switch using about 300 mA.
                    Wondering if the problem is related to the 2-volt drop across the ignition switch. Seems pretty high for what should be a dead-short. Wondering if there might be voltage spikes that are taking out the relay trigger.
                    As an experiment, you could try connecting the relay trigger directly to the battery through a fuse and see if that helps.
                    Just a thought.

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                      #11
                      I had the same lighting problem. I went over kill on relay -used one from Painless wiring kit. A 35A? weather sealed relay About $35. I had it left over from a car project. Has worked flawless for over 2 years. Connected it to be turned on by ign switch, send power direct from battery to fuse block supply side

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                        #12
                        I'm leaving on the big trip in about 11 hours. I put in a 40 amp unit today and mounted it a bit more loosely (old ones were 30 amp). It says it's good for 14 volts.

                        It's a two-minute job to restore it to stock. Well, it was ... it'll probably take more like 8 minutes with saddlebags. And if I have starter problems it's an easy job to bypass the ignition switch entirely (or just pull the headlight fuse temporarily).

                        tomm: I tried revving the bike to the moon in the garage watching the voltage. No problem. 4k on the street warming up the bike, dead. An intermittent connection on the main fuse or through the R/R sense wire would cause the voltage to go way up, but I dunno. That should blow some light bulbs. I need some ridiculously expensive data-logging multimeter. I might try your idea anyways of wiring the trigger directly to the battery and see what happens. (The last 2 relays had a coil resistance of about 80 ohms, which is ~ 150 milliamps.)

                        When this happens it's also taking out the main fuse, but if the coil shorts out inside the relay, that is expected.

                        Comment


                          #13
                          Check out the topic of 'de-spiking diodes'. They're explained in plain English on page 11 and 12 in this PDF:



                          I'm not concerned with the spike from your relay. I am halfway concerned with the spike from your ignition coils themselves when your relay disconnects them from +12v. I would think that the battery would absorb any inductive spike, but perhaps if you protected your relay coil with a common moderate-current diode (wired 'backward' to the coil's polarity) you might get some protection and longer life.

                          I'm not saying that this is the solution, but considering that it's your relay's coil side that's going belly-up, this is pretty much the only suggestion I can come up with. Cheap enough to try, though.

                          Those Bosch automotive relays should outlive the bike.
                          and God said, "Let there be air compressors!"
                          __________________________________________________ ______________________
                          2009 Suzuki DL650 V-Strom, 2004 HondaPotamus sigpic Git'cha O-ring Kits Here!

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                            #14
                            Originally posted by p_s View Post
                            I hung it on a zip tie next to the battery box. I figured that should have insulated it from the vibes well enough. I could glue it to some foam I suppose.

                            If it is vibration, then it can be wierd as far as what works better.
                            Sometimes mounting it springy works better, sometimes a harder mount is better.

                            One thing to watch for with a flexible mounting is if it can flex, but then if it flexes too far it bangs into something when you hit a harder shock.
                            That ends up worse than rigidly mounting it.

                            some things to try ...
                            a different mounting location,
                            just a different orientation of the relay (on its side, or on its front)
                            the foam mounting tape. (I believe the foam not only adds flexibility but also damping (think of the wire tie as a spring ... the foam is springs and shock absorbers too))
                            different relay

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