OP
OP
This is from my Service manual...
Voltmeter Question (I'm Back) :-)
- Thread starter Rogue_Bolo
- Start date
I put an ammeter on my GL1000. I don't remember where I got it but it was very close to the orange gauges of the VF1000 Interceptor I got years later.
The ammeter matched the Interceptor's orange lighting and the thing I liked about it was 0A was at the 3 o'clock position. When charging the needle was above 0A and below it when discharging. It was cool to see it noticeably above 0 on startup and watch it drop to ~0A after being on the road a bit.
Cool as it was I never wanted to do another one. Hooking up a voltmeter is some much easier.
Powerwerx also has Ammeters. They also have mounting plates 1 to 6 holes.
Also available with blue OLED.
Also available with blue OLED.
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Just to mention it, an ammeter is actually a voltmeter calibrated to read the voltage across a low-value, high-wattage resistor that must be inserted in the wire that carries the current (exc. starter) into and out of the battery.
The problem with wiring one in the ST1100 is that the charging current and the bike's running current have different electrical pathways between the alternator and the battery, and between the battery and the main fuse.
Would the same problem you mention exist with the ST1300? So you would need two separate sensors/shunts, that you could possibly switch back and forth to the meter?
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I'd have to see a 1300 diagram to answer you, but it would most likely be easier to relocate either the alternator feed connection or the main power wire(s) connection. Look at this generic diagram I found on the webs.
See how the Alternator and the Fuse Box share a single wire that the ammeter is inserted in? The same two wires on the ST1100 connect to the battery in different places, so a modification would need to be made.
OP
OP
It would take more effort to install an Ammeter because depending on the maximum current flow measured, the meter has to be installed in Series (in line) with the current being measured. Depending on the current flow, I may have to install a load in parallel with the meter to divide the current to allow to measured amount of current to flow across the meter. At that point, I may be introducing errors in the meter reading due to the amount of current the meter is reading, then you have to adjust for current ratios between the load current and the measured current (unless you are fortunate enough to have a meter that is calibrated for the parallel load in the circuit. Better for me to install a voltmeter which a large impedance to allow a much smaller current flow, and therefore less current drain on the Charging circuit. Thx all for your input so far. I have much food for thought. Another option for me to consider is an Ammeter that measures current using induction.
Then there is always KISS. 
Andrew Shadow
Site Supporter
Larry:
I have an electronic meter that can be used for measuring amperage in a DC circuit. It is rated to measure DC current up to 400 amps. It came with a shunt that needs to be installed in series with the negative battery cable. From the outside the shunt looks exactly like a piece of chromed flat bar, with no visible openings or resistors anywhere.
From memory, it is about five or so inches long and maybe two inches in width.
I never thought to put an Ohm meter on the shunt to see what its resistance is.
Do they calibrate the ammeter to work with the natural resistance that is inherent in that length/size piece of steel that they supply as a shunt?
Or, was that shunt manufactured with additional resistance embedded inside of it somehow to calibrate it to the ammeter?
That means it would have to carry starting current, too. Electronic ammeters tell you to use the negative wire so the electronics inside can use the same negative reference, simplifying the circuit.
The meter and shunt are designed as a calibrated set. The meter is designed to display current as its measuring voltage drop, and the resistor's power rating determines its maximum current capacity.
The same meter with a shunt of the same resistance, but of a lower power rating, would read the same current, up until the point where the resistor overheated.
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Andrew Shadow
Site Supporter
Correct. It is an engine analyzer intended to diagnose starter and charging systems on 12V vehicles.
This shunt in only maybe 3/16" thick, but it is not just a piece of steel? It has resistors of specific values built in to it somehow?
Nothing is visible from the outside except flat chrome looking steel plate.
No, the block of metal itself is the resistor. It's a very low resistance, a small fraction of an ohm, and it's large so it won't get warm while dropping the small fraction of a volt that the meter is reading.
OP
OP
Another type of meter I have worked with is the "inductive" type ammeter, which expanded on the D'Arsonval meter movement (on which all analog meter movement is based on). in that case the meter coil itself was used as a load. Contrary to popular belief, there is resistance in a conductive wire that is based on the type of material the wire is made from, as well as the diameter of the conductive material. As part of my naval "A" school training, I had to learn and memorize some "ugly" formulas regarding the interactions of conductive materials and the effects on signal output/sensitivity during my radio and RADAR studies. (flashbacks
). All of this is pretty much moot for me as I plan to install a Voltmeter instead of an ammeter.
Andrew Shadow
Site Supporter
Good, thanks.
That is what I always thought. I was getting a little confused by some of what I was reading.