GL1800Riders Forums banner

1 - 20 of 20 Posts

·
Registered
Joined
·
280 Posts
Discussion Starter #1
I have A Big Bike Parts LED volt meter. I always have had it wired direct off the battery. It has always worked great. I have a question. Does it matter where you wire it into? I mounted it on my leftside compartment lid and run the wire down under the compartment and wired it into the wires going to the power port that is in the compartment. It seems to work fine. I just want to besure I am getting a correct reading by wiring it in these wires.
 

·
Registered
Joined
·
7,613 Posts
Yeah, you will do ok there except nothing when bike if it's hooked to the acc plug
 

·
Vendor
Joined
·
17,403 Posts
Voltage is consumed in a circute. That means the longer the wire or the farther from the battery, the less the voltage reading will be since some of the electrical push getting the electrons there has already been used. Wire does have resistance but most mount it there.
 

·
Registered
Joined
·
19,989 Posts
Yes, it does matter. As Greg alluded to, a voltage drop on the supply wire to that connector due to a other devices in the circuit can cause a misreading.

In most cases, any one of the accessory connectors will match the battery voltage. And that is why many people attach their voltmeters there. But it is the word "most" in that sentence that is a problem. We have had a number of people on this board chase their tails trying to nail down an alternator/battery problem when all they had wrong was a problem in the accessory circuit. In my opinion, the accessory connector is a bad place for a voltmeter. The Electrical Connection voltmeter ties into the connector in the right hand pocket, which is tied to the same line, and is also a bad place.

The goal of a voltmeter is to monitor the battery voltage, so that is where your meter should be connected. For many owners, a voltmeter is just another accessory, like adding chrome. But if you want to make your meter a valuable battery/alternator monitor, it needs to be connected at the battery.

Obviously, connecting an LED voltmeter directly to the battery would be ideal, but it is not practical. It can drain the battery when the ignition is off. So you have to do the next best thing. The accessory terminals on the fuse block is the spot on the Goldwing that gives the most accurate readings with the least amount of hassle. At this connection, the voltmeter will not be as susceptible to voltage drops because the wiring run is shorter and the gauge of the wiring is heavier.

But even the accessory tap is not a perfect location because it is still sharing a line with other devices. That means you are technically still not monitoring the battery voltage.

If you want the utmost in confidence in your meter, the best method is to isolate the meter on its own power line. That means installing a dedicated relay just for the meter. This method will allow the meter to turn off with the ignition, saving your battery charge, and it will eliminate the potential for a voltage drop because it is not sharing the line with any other device.

I use a dedicated relay for my meter. But for most amateur installers, I recommend the accessory taps. It gives the most accurate reading you can reasonably get with the least amount of hassle or electrical knowledge.
 

·
Registered
Joined
·
3,551 Posts
I use a dedicated relay for my meter.
Can you recommend a relay, I have a spare one sitting here, for an air horn installation that's not going to happen, but that seems a bit heavy duty for this application.

Thanks
 

·
Registered
Joined
·
19,989 Posts
Use a standard 20 amp automotive relay. It is no doubt overkill, but they are cheap. It is not easy to find reasonably priced waterproof 12 volt relays in lower current values.
 

·
Registered
Joined
·
7,613 Posts
really how accurate does a voltmeter with only 12 leds need to be or how accurate can it be for that matter.
 

·
Registered
Joined
·
19,989 Posts
really how accurate does a voltmeter with only 12 leds need to be or how accurate can it be for that matter.
I expected that question. :lol:

You only need it to be accurate enough to know that the reading you are getting is a true representation of the voltage at the battery.

When all the bike's systems are functioning as they should, the meter will give you a reading that is "accurate enough" at any of the accessory connections. That is why these aftermarket meters that tie into any convenient location are so popular. They "seem" to work just fine where they are installed.

But a meter pays for itself when things are NOT working ok, like when a component fails, or when something wasn't installed correctly. Until that happens, it is just eye candy. It is not uncommon for one of these branch lines to measure half a volt to one volt lower than what the actual battery voltage is, leading the rider to believe he has a charging or battery problem. When I have a problem, I want to be confident I am reading the actual battery voltage, not some arbitrary branch that has voltage on it. When troubleshooting, I will measure voltage at many different points. But the starting point and most important point is always at the battery. This is troubleshooting 101, day 1.

I said earlier that the accessory tap is an acceptable place to get your measurement from. Even though it CAN give a false reading, it is far less likely. Attaching the meter at this point is so easy, and with virtually no additional cost that there is no good reason not to.

The dedicated relay is no doubt a little more involved, and does have some cost to it. For that reason, I don't blame anyone for not doing it. I use a dedicated relay simply because I want to remove as much doubt as possible, and have confidence that I am always measuring the actual battery voltage.

How important it is to you is a decision you have to make. I'm just sharing my preference. For those who buy meters just because they think meters look high tech and cool, they can install it anywhere.
 

·
Registered
Joined
·
180 Posts
Larry I've been pondering this question for awhile now never thought of the relay good idea.But what kind of meter do you use and where did you put it? I have an 08 with nav I'm just wondering?I want to be able to see it.I don't think I want to put hole's in my pocket covers so I'm not sure which meter to get
 

·
Registered
Joined
·
3,551 Posts
If I put one on, it will probably be a Lascar EMV 1200. I used this on my KTM 525EXC.



 

·
Registered
Joined
·
16,865 Posts
Now Larry! You are not fooling me for one minute. The moment you notice any indication of a voltage problem at your installed meter, you go get your technical meter and trouble shoot. Tell me I am wrong. So, if you mount the EC unit out on a branch circuit and you get a reading that is .705V lower than the technical meter reads at the battery termnals, then you could have that correction factor in your head. No?

Harrrrrrr. Thanks for good 'splanaiton!

prs
 

·
Registered
Joined
·
19,989 Posts
prs, you are absolutely correct. That is exactly what I would do. These panel meters are not troubleshooting tools and are not a substitute for one.

But wouldn't you rather avoid the anxiety of thinking you have a problem with your charging system or battery while on a trip? How many people carry a DMM with them while traveling? I would bet not many do. (I confess that I do.)

I am not trying to create a panic. A good number of people that use other locations to tap the reading will never have a problem. But the OP asked about the correct method to install the meter, and I gave him the choices that I feel are the MOST correct. Am I too picky about it? I don't know. Maybe.
 

·
Registered
Joined
·
19,989 Posts
Larry I've been pondering this question for awhile now never thought of the relay good idea.But what kind of meter do you use and where did you put it? I have an 08 with nav I'm just wondering?I want to be able to see it.I don't think I want to put hole's in my pocket covers so I'm not sure which meter to get
If you want a line of sight install, the Lascar meters are a good choice because they are small. Some are fully self contained, and some have waterproof bezels.
 

·
Registered
Joined
·
7,613 Posts
How's this for logic. Put it on an accessory line. If you get bad readings suddenly, suspect a faulty accessory and check the actual voltage at the battery. Harbor Freight often gives away multimeters on special days and they are $5 anyway.


http://www.harborfreight.com/7-function-multimeter-98025.html
 

·
Registered
Joined
·
19,989 Posts
That's the cool thing about knowledge. Once you are armed with all the information you need to make a decision, you can intelligently decide for yourself which method is best for you.
 

·
Banned
Joined
·
350 Posts
Voltage drop?

This argument about where to connect the meter seems silly to me. I am not a motorcycle mechanic but the resistance in 18 gauge Cu wire (solid) should be about 22Ω/km (even less for stranded). If the wire is Al about 35Ω/km.

Lets assume the Vcc is running 13.2Vdc and the length of wire in question is 20 meters using a 1ma meter.

The drop across the wire is trivial

In Al wire the drop would be 0.035Ω/m * 20m * 0.001A = 0.0007Vdc

Let's imagine there there is a factor of 100 times introduced by the meter and/ connections. You still get a drop of 0.07 volts. Hardly seems meaningful.
 

·
Registered
Joined
·
7,613 Posts
My thoughts too especially when your meter has just 12 "notification" LEDS, right john??

Posted from my HTC Incredible 'droid.
 

·
Registered
Joined
·
19,989 Posts
John, your calculations are wrong, and they are not simple to calculate. First of all, the accessory line is 20 gauge, not 18. When you figure in the routing involved, the wire is about 6 feet long.

Drawing 5 amps through that wire will result in a .311 volt drop in the wire. And this is in free air. In a bundle, the drop is much greater, but the calculation is too complex to mess with here. For the sake of keeping the discussion simple, I will stick with the .311 figure.

Then you have to factor in all the splices and connectors along the line, as well as the drop across the relay contacts. if you have never seen a Goldwing harness torn apart, there are a lot of spliced connections everywhere. When added together, that voltage drop can easily exceed the drop of the wiring, even with a mild current draw. And as the bike ages, the voltage drop across the various connections will increase. When totaled together, the drop can easily reach .8 to 1.0 volts.

There are many voltage drops like that in a car and motorcycle. Most devices work just fine with it. But the meter can lead you to believe all is not well if it is not hooked up near the battery.

I don't mind doubting the importance of meter location. In fact, I actually understand the doubt and realize I will not convince everyone. But I assure you that I have not overstated anything I have posted here. Anyone who knows me here knows that I do not jump on the "sky is falling" bandwagon. I downplay the extent of most problems. Again, this is not a serious problem. But it is still a potential problem. The best part is, the problem is easy to eliminate.

Just one example.

I got a PM from a member about a year ago. He had the EC meter and it was plugged into the heated grip connector in the right hand pocket through a Y connector. He thought he had a bad alternator or battery because every time he turned his grips on, the meter kept dropping as the grip controller turned the heat on and off. I told him to check the voltage at his battery. He borrowed one from a friend and the voltage was stable while the grips were on. I suggested that he relocate the voltmeter wires to the accessory tap at the fuse box. His problem, as well as his anxiety disappeared.
 

·
Registered
Joined
·
38 Posts
Voltmeter

Don't get your panties in a wad about the accuracy of your on-board voltmeter. All you want/need to know is if there is a problem with your charging circuit and/or battery. I used the Honda Marine voltmeter, mounted it in the right side shelter and connected it to the accessory terminal next to the battery. I now know at a glance if everything is OK or not. If I need to troubleshoot further, I'll use my Simpson 260.
 

Attachments

1 - 20 of 20 Posts
Top