Ameter Install

[3Phase]

Remote Shunt Ammeter

Nate,

What you're looking for is a Remote Shunt Ammeter.

With a remote shunt, the majority of the current to and from the battery flows through the shunt and only a small, proportional amount of current flows through the ammeter itself.

Almost all aftermarket automotive ammeters use an internal shunt. Internal shunt ammeters have the current shunt (surprise!) inside the gauge and the ammeter is wired in series somewhere between the alternator and the battery.

Remote shunt ammeters have the shunt wired in series between the alternator and the battery and the ammeter is wired in parallel with the shunt. With the ammeter wired in parallel with the shunt you can use #16 or #18 wire, add a fuse to protect the meter, and your bike won't die if the fuse pops or the ammeter fails.

I found one example of an ammeter and remote shunt from Westach:

Ammeter
Model: 2C6-22
Price: $60.15
Amp: -30-0-30 adc, 2" round, 50 mv f/s

Shunt
Model: 237-30
Price: $45.00
Shunt, 30 amp, 50 mv

http://www.westach.com

[Jerry]

Off-topic...

But for smaller applications like my 41 Ford tractor

I have a '48 8N Ford with a 9N engine. Bought a '52 8N for parts mostly because it had the correct engine for the '48. Eventually I'll have one correct '48 with the upgraded (twin oil seal) later rear axles.

Amp meter does work but it's biggest use is to let me know the voltage regulator is doing its job. If the regulator quits or is not doing it's job - and it does stick once in a while - the gauge gives me a visual indication of the problem.

Keep in mind the meter will need to be in series with the battery's charging circuit. You would need to hook one side of the meter to the battery and the other to the charging output of the voltage regulator. (I don't know off-hand which lead from the regulator this would be. Consult a wring diagram.) 14 gauge wire at a minimum, 10 or 12 would be better.

[natemoen]

This really has nothing to do with the ameter anymore cause I got that in. I was thinking I would hook all the other gauges up to the negative side of the ameter and have a near direct con ection the the battery. Well, I hadn't thought that all the way through and forgot that they ground separatly and would then always be on...

I could hook them back up the way they were but I didn't like that cause they weren't really getting clean voltage and wasn't accurate I guess. I am looking for something closer to the battery, any thoughts?

Apparently I need to go through and clean some connections again cause I was checking voltages and the battery was 12.78, main fuse was the same, and the 20 amp fuse with the thick brown wire was 11.72.....

[3Phase]

Sorry about that, Nate

I thought you were still looking everything over before getting an ammeter.

The voltage drop you mentioned is probably in, or next to, the headlight shell. The ignition switch and the ignition switch connector can both get dirty and eventually burn.

I'm assuming you're more or less happy with the ammeter you installed and you're asking about a better location for an auxiliary power tap for your other gauges. There's a Brown wire with a bullet connector in the headlight shell that's made just for something like that. It provides 30A switched battery power because it's tapped into the same Brown wire that feeds the fuse block from the ignition switch. You can hook up almost anything you want but you will have to fuse each item.

Again, if the ignition switch or the connector get dirty you won't have battery voltage on the Brown wire (switched battery power), you'll have battery voltage minus the voltage drop across the switch and connectors.

.

[natemoen]

Sorry Scott, I started this thread a month or so ago and just brought it back the other day to double check on that wire.

I will check on that brown wire, sounds perfect. I had already put a fuse on the other gauges since I was thinking I was going to hook them straight to the ammeter.

[natemoen]

Ok, I do seem to be loosing that volt through the ignition. I have battery voltage at the red wire going into the ignition and then roughly a volt less coming out on the brown wire. I show no resistance through the key and it is still clean as a whistle and lubed up.

WTF?

[IanDMacDonald]

What's the resistance of the brown wire? I'd chalk it up to voltage drop and not fret about it.

[natemoen]

Dropping a volt within 4 inches with no resistance measured in the unit.......

[IanDMacDonald]

Yeah, okay. Going with the dime or less test on VD, either way I guess that is too high. My best guess would be two things Nate:

1. The contacts in the ignition overheated and that's where your VD is being caused from.
2. Whatever connections are between that ignition, etc., are corroded, causing the VD.

Have you swapped out the ignition with a switch to see if it alleviates the problem? If so, you either chalk it up to old parts, or replace the switch.

[natemoen]

I took the switch apart aleady, everything is clean and tight inside the ignition switch.

The measurment I took was from the connector just off the switch, couple inches of wire going to the switch, couple more coming out of the switch to the connector. No resistance shows on the meter. Same voltage as battery is measured up to the switch but then coming out I loose a volt.

[IanDMacDonald]

You know what I'm thinking Nate? Bad ground. Try to run a ground wire straight to the ignition switch from the battefy, and then check ur voltage.

[natemoen]

There is no grounding needed on the ignition, it is just a pass though device.

[3Phase]

AUX Connector and Voltage Drops

Nate,

Honestly, I've been planning to install an ammeter for over five years now but I strapped a five dollar Harbor Freight voltmeter to the right-hand side of handlebars shortly after I bought Columbo. Now I just stare at the bike and wiring every few months/years with the ammeter in my hand and put it in various locations while I think about how to connect and mount it, then I put the 'meter away and go find something else to do until the next time I need to gather some fresh wool.

Back to your bike! First: I was wrong! about the Brown wire and AUX connector in the headlight shell and it's not 30A switched power.

It is a switched power wire but it's returned after the 20A SIG fuse. The entire Signal circuit after its 20A fuse is a busy little circuit and inside the headlight shell is a 2-pole female bullet connector. It looks like an insulated oversize shiny brass female spade connector and the front brake light switch Brown wire uses one pole, the second pole is left open for AUX.



For testing the Harness connections and the Switch your handheld meter isn't going to work reliably for measuring resistances less than 1 Ohm. Yes, it's a short loop but there are a lot of connections and they all normally have full Amperes flowing through them, not milliamps from a test meter.

Where and how, exactly, are you measuring the voltage drop at the Ignition switch?

Set the handheld meter to DC Volts and measure the voltage drop across the Switch. If you have an autoranging 'meter you should get a reading. If you don't and/or it's not in the correct range, use the next lowest DC Volts position on the 'meter and try again.

For the Ignition Switch, the Harness side of the connector is male and the Switch side is female.

Voltage drop across the Switch only:
Switch Red --> Switch Brown

Voltage drop across the Harness connector only:
Harness Red --> Switch Red
Switch Brown --> Harness Brown

Voltage drop across the Switch and the Harness connector:
Harness Red --> Harness Brown
Harness Red --> Switch Brown
Switch Red --> Harness Brown



Sooner or later you'll find the voltage drop but remember that this is supposed to be fun so enjoy yourself and here's a link to more about measuring low resistances than you probably want to know!

Robotroom.com: Measuring-Low-Resistances.

.

[natemoen]

Well, I had to put things back together as is for now.

I will have to check into it like you said Scott and update at a later date. Thanks for your help, glad you are back as our electronics guru!

[crazy steve]

Remember Nate, that voltage drop is directly related to the load on the circuit, so I assume that you're checking the switch for ohms while it's unplugged, then plugging it in for volts. Once connected, you'll have a load unless you disconnect/remove fuses from various circuits, like the taillights, ignition and alternator, all of which will be powered up to some degree when the switch is 'on'.

If you look at this: http://www.xs11.com/forum/showthread.php?t=35339 .... you'll see that the resistance needed to drop 1 volt is extremely low depending on load, likely at or below the resolution threshold of most meters. Checking with the method Scott linked to will tell you what you have in terms of resistance, but you may not be able to improve that due to the mechanical limits of the switch. Try stretching the springs that apply pressure to the contacts and remove all 'excess' lube that may be getting on the contacts.