System Relay Mod

[Guest]

System Relay Mod Synopsis

When I started reading about all the various relay mods and accessories being added, I became curious. I wondered whether any or all of these mods could be combined. If so, how would I go about it? I also wanted to place a permanent line to connect my battery tender. Then I saw the mod to turn the headlight off while the starter was engaged and I was hooked. I put pen to paper, combining the various mods into one cohesive unit. I finished my work and tested it, and it works as designed.
These are the mods combined into one:
Coil relay mod
Ignition switch mod
Horn relay mod
GPS, Grip heaters, accessory port, battery tender, and just about anything else you can think of (that your charging system can support)
And it turns the headlight off while the starter is engaged.
The document includes a system diagram, tools list, parts list, and possible sources. It also explains how to do certain things, such as soldering, debugging, testing, etc.
Constructive comments are welcomed and appreciated.
Click on the link and download the file.
(The file is a bit large (about 10 MB) because I also included hi-res pics so you can follow along with the text.)

System Relay Mod with printing enabled


Coming soon: GPz Relay Mod. A twist on the original System Relay Mod:

• The GPz turns the headlight off until the bike starts, so the headlight mod is not required.
• The ignition switch is fine, so there is no need to modify that circuit.
• I used a commercial ganged fuse block, so there is no need for a terminal strip and inline fuses.
• I have a MotoBatt AGM battery which has 2 sets of terminals for both 12V and ground, so I used the second set for the relay mod.
• No wires were cut anywhere, so converting back to OEM is a simple as plugging the original wires back into the circuit.
• Since the airbox is removed from the GPz, more space is available for mounting the system.

[bmac]

Well done and excellent step by step presentation. Thanks for your initiative to research and put into text this mod for the members to use. Bob

[posplayr]

Thanks for the detailed write up. A lot of members will get a much better appreciation for doing a detailed technical write-up and a nice description of electrical techniques for these motorcycles.

You are adding a lot of expansion capability and have what looks like 100% growth. At some point you have to look at capacity and total load. I'm assuming you have separate ways to control these other loads when you are not at speed. Actually all of these extra loads are good because they reduce the current that would otherwise be shunted in your stator making it less likely you would even need a SERIES r/r.

I know you had the stated objective to minimize changes to the harness, and in fact to the extent that you can divert current away from the primary OEM current paths, you are improving the loading on the stock harness and so keeping it stock is warranted as it is achieving more design margin (it is probably marginal as stock) with these types of mods.

However to make sure that you are not taxing the stock wiring with all of the additional devices you have to be a little careful with how you connect your +12V fused source and where you return power for all of these external loads. You want to pickup points where you are not sharing current with the rest of the harness. In fact another thing you don't want to do is share current is add additional current on wires running between the battery and the R/R.

So we are lead inextricably back to a discussion of power and grounding. I think this link probably has a descent enough discussion.

http://www.thegsresources.com/_forum/showthread.php?t=139115

The "T" is recognizable from the schematic but is the eqivalent to the output of the R/R (+) in the figure below. In this figure it should be clear that if you pick up power from the solenoid that the current coming from the R/R has to go through the OE fuse box.




this one shows the "T" right at the output of the R/R and is more representative of the R/R battery fusebox relation than the one above.





Point #1 all average current comes from (or out of ) the R/R(+).==> this is where you want your single point distribution to originate
Point #2 all average current returns to (goes back to) the R/R(-). ==> return all current to this single point ground.

So if you recall in my write up I talked about single point grounds and also at what point to distribute power from.

The best place to return all the current is to the single point ground at the R/R mounting bolt. That mounting bolt should have a heavy wire to frame, to the harness and to the battery. In the case of KK mod all the return current will get back to the same point. So unless you bring the return back to here you will be sharing current with something else. I'm not sure of how KK's R/R is exactly connected but the single point ground is the lowest potential for the bike. See this link for details.


http://www.thegsresources.com/_forum/showthread.php?t=152769




So now the more complicated part of the connection where to tap off for the +12V unswitched. In principal you have the same issues as grounding. You want to avoid sharing current.

The source of all power is again the R/R (+) except of course when the R/R is shunting (or engine off) and the power comes from the battery. There are some variations to the way these harnesses are configured but the highest voltage potential in the system is at the "T" in the harness.

This is where the R/R (+) and the fused battery lead come together. Pulling power from that point is the best you can do. In fact although I did not document it, when I rewired a handlebar power outlet, I figured to kill multiple birds with one stone. I opened my harness up (where the R/R (+) red wire enters) to find that "T" and to help get rid of those pesky voltage drops ( see stator pages Phase A for the tests) I relocated the relay mod pickup point to the T.


So KK, I would go back over these two primary connections:

If your Mod ground doesn't go right back to the R/R (-) single point ground how is it going to get there? You don't want to share that current with the charging current wire between battery and R/R. A frame/chassis ground is OK if your single point ground has a strap to frame as well.

On the R/R (+) T side, the way I think you are connected which is the solenoid HOT, then all of the current from the R/R(+) is running though your OEM fuse box to get to the battery and then to the solenoid where you are picking up power. The "T" is much better for the reasons described. It would avoid accessory current through the OEM fuse box.

You might have accomplished this but I'd be guessing because without the harness schematic and knowing exactly where those fuse box connections/cuts are I'm not sure. By going right from the "T" on you don't need to change or snip any other fuse box/harness wires for Mod power.

[azr]

Well done everyone!! what a great write up. I'll have to put this on my winter to do list. I really like the 'all together' function of this mod, absolutely great. Thanks!

[cowboyup3371]

I downloaded the write up and will read it tonight.

[cowboyup3371]

That's interesting JC...it never made me sign in for it and I don't have a live.com account

[koolaid_kid]

It's a doc file, not a pdf...
- JC

Thanks for pointing that out, I fixed the link. It is my understanding you do not need Live installed just to download the file, IDK.

[duaneage]

Don;t forget a 2 inch bolt on the regulator to hold all those ground wires.

[koolaid_kid]

Well crud. Someone pointed out that the PDF creator I used cut off some lines at the end of each page, and they are correct. I will attempt to remedy this a.s.a.p. and report back when it is fixed.
My apologies.
PDF is now fixed. Not sure what happened the first time, I have used PrimoPDF for years now and it was the first time it burped.

[koolaid_kid]

Don;t forget a 2 inch bolt on the regulator to hold all those ground wires.

Now cut that out, to each his own. Besides, this is a metric bike and it needs to be >= 50mm. (These are all tongue-in-cheek, folks, let's have a little fun while we try to improve our GS experience.)
When I selected my ground point, I used the continuity function on my multimeter, just as I have always done, even on my race bikes and cars.
GSR members must make their own decisions, as they usually own the bike being modded.

I have also been told the current PDF has printing disabled. As soon as I get home this evening I will rectify the situation. Mea culpa.

Situation rectified, should be printable. LMK if it is not.

[BassCliff]

Hi,

Great thread! Nice work! I'm very impressed. I guess I have to start doing a better job on my write ups.


Thank you for your indulgence,

BassCliff

[bakalorz]

Increasing the reliability of the system relay mod.

As people have been making the coil relay mod and this one, they have sometimes been worried about reliability, and what will happen if the relay fails.
On some of the threads they have advocacted carrying a spare relay in the toolkit.
There is a simple fix which will greatly improve the reliability of any of the relay mods, including this one.

The fix is inspired by the ignition system on Light aircraft like Cessnas etc. which have dual redundant ignitions.
If either system fails, the engine continues to run on the other one.

We can put dual redundant relays on our bikes.
If either relay fails, the bike will continue to run on the other one.

To implement the upgrade, all that is required is a second relay of the same type as you are already using and two normally closed momentary switches.
I have modified your schematic to show how it is wired.

The second relay (relay 1A) is wired in parallel to the first.
The switches (S1 and S1A) are wired into the coil circuit of each relay.
These type of switches usually make contact, but when they are pressed they break the circuit.

When both relays are working, relay circuit works exactly the same as it did before.
If one of the relays fails, the bike runs the same as it did before.

Since the bike continues to run normally even if one of the relays fails, we need a way to easily test the relays and make sure both are good.
This is where the switches come in.

Periodically the following test is performed while the bike is running:
1) briefly press switch S1 and release it, the bike should continue to run (using relay 1A)
2) briefly press switch S1A and release it, the bike should continue to run (using relay 1)
3) briefly press both switch S1 and S1A, the bike should shut down.

Aircraft practice is to test every time before take-off. I would recommend tests 1 and 2 every day you ride, test 3 could usually be skipped, maybe do it once a week or once a month

If the bike stops during either test 1 or 2, then the other relay or its switch has failed. You can restart and continue to ride the bike, but your safety margin has now been eliminated.
(you are effectively now running the same as a "non-upgraded" relay mod)

If the bike continues to run during test 3, then one of the relays has welded its contacts together (or one of the switches has failed closed)
If a relay has welded its contacts, even when the ignition key is shut off, the relay will still power the bike.
In this failure mode, the bike can still be ridden, but since the power to the bike will not shut off even if the key is turned off the battery will drain.
(this failure mode is possible with a "normal" relay mod as well as the upgraded one described here. It is however fairly rare.)

[koolaid_kid]

bakalorz, I like that on several levels
First, it adds testability to the circuits.
Second, as you pointed out, it provides redundancy so you can still ride if one fails.
Third, and very important to me due to space restrictions, it allows me to put the second relay, along with the switches, somewhere easier to reach than the side of my battery box.
Well done, and thanks.

[bakalorz]

bakalorz, I like that on several levels
First, it adds testability to the circuits.
Second, as you pointed out, it provides redundancy so you can still ride if one fails.
Third, and very important to me due to space restrictions, it allows me to put the second relay, along with the switches, somewhere easier to reach than the side of my battery box.
Well done, and thanks.

One final note ... you don't HAVE to use normally closed momentary switches.

They make it oops proof and easy to test. But you could use normal switches, just make sure you leave them "ON" at all times other than testing.

[koolaid_kid]

One final note ... you don't HAVE to use normally closed momentary switches.

They make it oops proof and easy to test. But you could use normal switches, just make sure you leave them "ON" at all times other than testing.

While technically correct, I always prefer to build testability in where possible (but that's just me).
For those not familiar with momentary switches, they come in toggle or pushbutton, standard or mini size, red or black (usually). Since they only act on the trigger wire, which carries very little current, 18-20 gauge wire may be used and the switches can be remote mounted for easier access.
I plan to use a red and a black mini on the GPz, which I also plan to ride to the BC rally, for those who are attending.