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I am running a Stella gas tank and headset on my P200. I have a custom made wiring harness for this. Currently I am running regulated AC (12-14 volts) to the fuel gauge and the grey wire goes back to the sender at the gas tank.

But yesterday on my test run on the scooter the gas gauge didn't seem to work properly. It seems to rise when the motor revs higher.

Can someone test out the wires on their gauge and let me know what type of current goes to it?

Please let me know what voltage the gas gauge is supposed to be fed and if it is supposed to be AC or DC voltage. I have both at the headset.. so it would not be a big deal to change it.

Thanks for any tips.
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I could be wrong, but I'm pretty sure it's DC. Try running a line off the battery, see what happens.....
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Molto Verboso
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I see why you needed that gas tank now Mike....is this part of your CORSA setup?
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Yes it's the my corsa ride. I am trying to get it all dialed in before the race.. and of course there are electrical gremlins.
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The way those fuel gauges work is like this.

The fuel sender is a variable resistor. This creates a voltage drop when power is run thru it. The higher the resistance, the larger the voltage drop.

The fuel gauge in the headset is a pretty dumb device. It is basically a metalic strip coiled around a shaft with a needle. As power goes thru it, it heats up, and this uncoils the coil and moves the needle.

While most of these are run AC, it would function on DC as well, albeit with a possibly slightly different reading.

Now, there are two. Things that will skew the reading.

One is if you put a different voltage into the sender/gauge circut. Higher voltage in means more voltage to the gauge at the same fuel level. This is probably what you are seeing. Rev the engine, the voltage goes up, especially if you have alot of load on the system that exceeds the capabilities of the stator at idle.

The other is the outside air temprature. If it is cold out, it will take more voltage to heat the coil and move the needle.

If you want accuracy and consistancy,, you need to minimize thes two variables.

There is another way, though. It's more acuurate. That way is to build a comparitor circut. This has a resistor of known value that it puts the same voltage thru and compares the voltage drops. If the voltage drop across the fuel sender is more than the voltage drop across the known resistor, it lights a light. This gives you an 'idiot light'. Stack several of these circuts with different resistors, and you get a bar graph fuel gauge that will be acurate across a range of voltages and regardless of temprature. This mess of circuts is easier to make than it sonds; you can get a stack of ten built into a single chip off tne shelf specifically designed to drive a column of LEDs.

If you want more info, let me know and i can post the details of that chip when i get in front of a computer.
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rob hodge wrote:
The fuel gauge in the headset is a pretty dumb device. It is basically a metalic strip coiled around a shaft with a needle. As power goes thru it, it heats up, and this uncoils the coil and moves the needle
really!
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The Stella wiring diagram shows the power supply is AC, although there is a diode in the gauge to rectify it. This actually feeds 2 coils, in parallel, placed at 90° to each other. One coil terminates to earth, the other is connected to the sender unit.
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firekdp wrote:
The Stella wiring diagram shows the power supply is AC, although there is a diode in the gauge to rectify it. This actually feeds 2 coils, in parallel, placed at 90° to each other. One coil terminates to earth, the other is connected to the sender unit.
i'm not surprised. it's been ages since i've had one apart and that one was a much older piaggio unit. i remember thinking it wasn't the best way of doing it when i saw that one.

either way, the voltage o nthe AC line affects a magnetic gauge the same way.
Vader19 wrote:
really!
it wasn't like it got warm to the touch or anything. it was a several foot long watch spring that probably grew like half a mm when current was passed thru it. fiddly little thing.
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Sounds like the way to go would be to use a stella wiring harness and regulator/rectifier and just match my stator's output to tie into the harness.

I don't have time to fiddle with electronics or swapping out the harness before the Corsa IFP.. so I suppose I'll just run with no fuel gauge...

OR.. I may install my digital SIP PX200 speedometer.. would I be able to get any better results from that.. it's got a gas gauge in it also.. I am not sure how well it will mate with the stella sender

Also FYI my stator sends AC voltage out directly out to power the headlight, tail light (not brake light), and the lights in the speedometer.. that's it. And it's regulated with a MSR Voltage Regulator (clipper) that limits the AC to 14 volts maximum.. but it's a very strong 14 volts. My headlight is super bright.

I am not going to get too worried about it.. as I have bigger priorities than worrying about my gas gauge and/or the SIP speedometer.. I kind of don't want to trust the SIP unit on the corsa because failure of the electronics would be VERY bad for the corsa since you need to use the odometer to know when to make turns - and if this craps out then I ma screwed big time.
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mikefrombaltimore wrote:
so I suppose I'll just run with no fuel gauge...
Get the BGM Fast Flow w/ LED Fuel Gauge.

It'll let you know when you hit reserve if you wire a light inline with it. I have them on my bikes.

I can't count how many times my bike died on the highway at 65mph because I ran into reserve.
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Travis,
I have heard that the fast flow tap with low level light has a pretty high level of gas left in the tank when the indicator trips.

What is your experience with it?

I mean if the light goes off at 1/2 tank level then it's really not that great.

I'm looking to have a light come on when I have about 1/2 gallon left in the tank aka about a 20 mile range left to find a gas station or plan to refill my tank with a gas can.
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Re: Stella Fuel Gauge and Sender in a P200 - how do I wire t
mikefrombaltimore wrote:
I am running a Stella gas tank and headset on my P200. Thanks for any tips.
It will work, I did the same set up on my P200. I don't remember it being any thing other than just hooking up the wires per the print. I think I used a complete Stella wiring loom. I'll look thru my notes later today.
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mikefrombaltimore wrote:
Travis,
I have heard that the fast flow tap with low level light has a pretty high level of gas left in the tank when the indicator trips.

What is your experience with it?

I mean if the light goes off at 1/2 tank level then it's really not that great.

I'm looking to have a light come on when I have about 1/2 gallon left in the tank aka about a 20 mile range left to find a gas station or plan to refill my tank with a gas can.
Seems pretty low to me, but I've never really measured it.
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As Rob98801says, as long as it is wired correctly to power, earth and the sender, it should work. On the stella, grey is AC power in, white to the sender and black is earth.
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I may have reversed the AC Power in and the Sender Wires..

I believe I had grey going to the sender.

Maybe that will fix the situation.

Thanks
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mikefrombaltimore wrote:
I may have reversed the AC Power in and the Sender Wires..
That's what I was thinking.
Connected correctly the coils will balance, no matter what the voltage, leaving only the variation in the sender resistance to unbalance it and move the needle. If the wires are reversed they can't balance and any voltage change will affect it.
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mikefrombaltimore wrote:
I have heard that the fast flow tap with low level light has a pretty high level of gas left in the tank when the indicator trips.

My BGM light just went on.. it's on my small frame, but the fuel is 6cm from the bottom of the 16.5mm-ish tall tank. The tank as you know is narrower at the bottom so maybe 1/4 tank? ish.

If you look at the BGM tap.. the light goes on when the gas is just below the pole that sticks up with the float and copper contact, and it should sit about the same 6cm (when it's dropped enough to set off the reserve light) from the bottom of any tank.
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I have a BGM fast flow on my P200. I find it lights at 3/8 tank, consistently. My bike gets 40mph consistently and it lights at 50 miles after fill-up. That gives me about 30 miles after it lights.

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