Adding a Relay for the Accessories

[mcgovern61]

I am in the middle of rebuilding my '82 wire harness and upgrading the system to modern fuses and relays. However, I ran into a minor issue the other day. I had to travel to the Boston area by train last week and did my usual of hooking up the trailer, loading my suitcases and riding to the parking garage at the train station. It sure is fun riding like this to work and travel!

This time though, after I crossed the bridge into Philadelphia, I git stuck is some real bad stop and go traffic. It was about 93 degrees out with pretty high humidity and the asphalt was running pretty hot. The fan was working normal, but coming on quite a bit while stopping in traffic. I noticed my voltmeter reading 10.8 VDC at times and was very concerned that the battery was taking a big hit as well as the stator. :shock:

This is the first time I have really got stuck in traffic with the trailer. The trailer lights are still incandescent. I have not installed the HF LED lighting kit yet.

With holding the brakes a lot, the trailer lights and the brake lights on the bike were really pulling juice while the fan was running. To make matters worse, the horn stopped working (I assumed not enough voltage to push the compressor). I could hear the horn relay clicking under my seat, but no horn. I made it to the train station fine and in the last ride around inside the garage in 1st gear and 3K RPM, the voltage came back up.

3 days later, a lot cooler and closer to night time, I arrived back in Philly. Thankfully, the bike fired right up no problem and got back up to 14.2 VDC on the meter. Now, I might be overstating this, but I find having a voltmeter to be invaluable with this system on this bike.

 

[mcgovern61]

This weekend, I finally got a chance to look at everything to see if anything was out of order. Still no power to the horn. Put a meter on it and hit the button, no power at the horn at all. I assume the relay must have failed (but I am thinking that is unlikely). Pull the seat and tank off to check connections at the relay and all is good. Try again and the horn works this time. Stuck relay???? Naw, I could hear it clicking!

Start to follow the wires and, stupid me, I never hooked the negative wire back up to the battery when I was testing the other wire harness.

It just happens that the wire was behind the battery and inadvertently making contact with the battery box. Re-hooked to the battery and horn is fine again. :heat:

This has got me to wondering about the load on the battery and wiring with the original system. The horn and trailer lighting run directly from the battery so I am not too worried about them messing with the small wiring in the glass fuse panel. But the radio and voltmeter are running from the acc terminals on the fuse block. The voltmeter is really only measuring voltage in the system at the fuse panel and not battery voltage. Pic of the meter:

 

[mcgovern61]

I know the new relay/fuse panel will re-distribute the load fairly well, but my concern is whether the system can handle the load? Measuring voltage at the acc terminal on the glass fuse box isn't the best place to make an assessment about the system condition overall, but it speaks to the fact that there are wild fluctuations in the wiring right at the fuse box and the system really takes a hit when the fan comes on. My new distribution will be putting the fan on a its own circuit running from the second buss bar.

I decided to start measuring voltage at the battery and watch the voltage meter as the bike cycles through the fan coming on, holding the brakes, running the radio, keeping the trailing hooked up and blowing the horn.

The battery dropped as low as 12.2 volts with all of that running at idle. But the voltmeter was reading 10.8 volts. That is a pretty big voltage drop.

So, how accurate is the voltmeter? I pulled the wires off the acc terminals and ran alligator clips from the meter directly to the battery while leaving my Fluke multimeter on the battery terminals. The voltmeter is within .5 volts from the Fluke multimeter. No too far off in my opinion. +/- half a volt could just be the alligator clips and length of wire. So the meter is pretty good. Why the low voltage readings?

Well, I am under the opinion the wiring is just too small at the fuse panel to handle voltage drops from big items running like the fan. I would rather have the meter measuring voltage at the battery. The best way to do that is run a relay that will shutoff the meter when the key goes off. But what do I use for a trigger? Well, the acc terminal is really too small the handle the voltmeter and radio, so, why not use that as the trigger and run a new wire from the battery.

Once again, I cannot tell you how much help it is having the connectors and tools from Vintage Connections to make up new wires and connectors. I pulled the voltmeter wire, added a 2 conductor connector to it, ran it down to the fuse panel and ran a new wire from the battery with a fuse holder. New trigger wires to the acc terminal and ran a "Y" connector from the ouput of the relay to run a wire to the voltmeter and a new connection for the radio. I ran the negative wires to a ground point under the relay (Bolt that holds the fuse box in).

 

[Rednaxs60]

This happens when an alt mod is done. The volt meter on my '85 LTD reads about 5 VDC less than actual at the battery. Lots of loss through the wiring.

Put new Fiamms Freeway Blaster horns on the '85 and had to install a separate relay for the horns and a separate supply from the accessory fuse block. Too much load for the original wiring and fuse. Would recommend a relay for yours as well.

With your new to you fuse block, you could easily add a circuit for the horn and trailer lighting. Might be able to separate the radio and voltmeter and run separate wires as well. Going to try to do this with mine.

For a relay trigger there is not a huge voltage requirement. I would run a wire from the engine stop switch that could come from the coils (black/white striped wire).

I also have a separate wire directly from my accessory fuse block that I installed a while ago that connects to the coils. This takes all parasitic loads off the 12 VDC wire going to the coils. The accessory fuse block is switched on/of by a relay that uses the engine stop switch as a trigger.

Just a thought.

Cheers

 

[mcgovern61]

Re-ran the same tests with everything turned on and now the voltmeter reads within +/- half a volt of what the battery is actually reading. A great improvement with very little fluctuation. But I noticed something else. Now that I moved those two items off the acc terminal, the battery is no longer dropping below 12,8 volts even with the fan on and trailer hooked up. Better yet, the top end voltage at idle is running 14.8 volts average. At idle, the voltage did not drop below 12.8 but as soon as I let go of the brakes, the voltage popped right back up to 14 at idle.

I have measured voltage at the battery many times in the past and I do not recall the voltage ever popping back up to 14 volts that quickly even with the fan running at idle. I am starting to think that the connection of these items to the acc terminal was too much load on the wiring and the voltage regulator was getting a bad reading before this and not working correctly.

I tried again with everything on, radio, headlight, turn signals, trailer hooked up and pulling the brakes plus the fan is running. Darn if the stator is keeping up very nicely now even at idle!

Once again......lesson learned. :head bang:

 

[Rednaxs60]

Nicely done - still trying to digest what you have done as it is not that dissimilar to my '85. Always look forward to reading of your posts.

Cheers

 

[mcgovern61]

Rednaxs60 » Sun Jun 18, 2017 7:41 pm[/url]":11offnm8]
Nicely done - still trying to digest what you have done as it is not that dissimilar to my '85. Always look forward to reading of your posts.

Cheers

Thanks! It is a bit hard to follow sometimes because I still have an '81 wire harness on the bike. The '82 harness (that actually belongs to the bike) is the one I am rebuilding with the relay/fuse panel. This mod here was specifically for the harness that is on the bike. Some of the other wires and cables I have installed are for items that are now permanent to the bike (like the radio, speakers, horn relay with the Stebil Nautilus horn and the trailer wiring) while other items are only temporary add-ons to the '81 harness while I am still riding. It will be a big day when all of the '81 items come off the bike and the new '82 items are installed.

The funny part about all of this is that it all started because I wanted to restore the self cancelling turn signals to the bike and learned how many components make up that system. I had stripped so much of that stuff off the '82 when we got mostly because I had no idea what the stuff was and much of it was rusted and corroded anyway. The bike was dead and sat outside in the weather for 12 years before we got her.

 

[Ansimp]

My cheapy cig plug voltmeter and temp gauge reads about 2 volts below system voltage. When I pull the Vetter fairing I will improve all the connections and provide a quality battery feed and use a relay for the accessory/ignition circuit. :yes:

 

[desertrefugee]

mcgovern61 » Sun Jun 18, 2017 5:09 pm[/url]":3nbgu1sn]
... I am starting to think that the connection of these items to the acc terminal was too much load on the wiring and the voltage regulator was getting a bad reading before this and not working correctly.

Hmm. I'm not sure about this. A heavy load and resulting drop seen by the regulator should have the opposite effect, right? The charging voltage should go up. That's what the regulator does, respond to the sensed level.

I believe it was just the pick-off and reference points for your meter. It sounds to me like the charging system was/is working just fine. You've described some pretty worst-case conditions, but no issues encountered. While I love having a voltmeter, sometimes they cause more worry than is warranted. I use them for reference more that absolute accuracy. If you know your bike's nominal operating range, it really doesn't matter how accurate the gauge is, you'll still know pretty quickly when there's trouble.

...but sometimes a piece of masking tape over the gauge can be the most effective fix!

:headscratch:

 

[mcgovern61]

..but sometimes a piece of masking tape over the gauge can be the most effective fix!

:smilie_happy: :smilie_happy:

 

[brianinpa]

mcgovern61 » Sun Jun 18, 2017 7:28 pm[/url]":3tj3lrkg]
Now, I might be overstating this, but I find having a voltmeter to be invaluable with this system on this bike.

It may look out of place or out of style, but I had two choices when I was working on my 87... A volt meter from a 78 or an 1100. I went with the 1100, but yes, it is invaluable.

 

[desertrefugee]

Before you guys think I'm anti-gizmo (I'm actually an Electrical Engineer), I'll respectfully throw up this shot of my dearly departed '84 Aspencade. I put a Honda Marine voltmeter on that one - along with a power port. I liked the analog Honda gauge.

(Miss that motorcycle)

 

[mcgovern61]

I have an analogue gauge that I used to have mounted in the Vetter fairing, but it is open to the back and no place to mount on the Standard. I prefer analogue over digital any day!