Temperature sensor malfunction

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Mik
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Temperature sensor malfunction

Can anyone here diagnose what is wrong with the temp sensor system of my Vectux?

The max temperature displayed is always about 6degc higher than the actual temperature, but using Scooterdiag reveals that the reading from the sensors are completely erratic.

Photobucket

All temperature values except for "Ambient Temp 4D" are relatively constant, they don't change or jump around while I look at the screen.

But "Ambient Temp 4D" bounces about in a seemingly random fashion every few seconds. I have seen values as low as 11degC and as high as 70degC while looking at it for a minute or so.

The battery warning symbol comes on a lot due to this malfunction, and the activation of the cooling impellers during pre-charge cooling delays is erratic, probably because the impellers will not get turned on when the system "sees" the ambient temperature as higher than the battery temperature. Sometimes the impellers come on when they should, sometimes not.

Any help with this would be much appreciated!

PJD
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Re: Temperature sensor malfunction

The temperature sensor, presumably a thermistor, is probably bad. Thermistors are tiny, delicate and and not waterproof unless they are potted or encased in something (not just a piece of shrink tube), which they should be, but maybe Vectrix didn't do so. I had a poorly-protected battery pack thermistor go bad on my current C124 after its first ride in rain, (open circuit). John's old programming would interpret this as an emergency (battery pack about to burn up or such) send a "hot battery pack" code to the indicator light, and completely disable the scooter. My temporary fix was to replace the thermistor with a trim pot so I could spoof a correct temperature.

ofx210p
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Re: Temperature sensor malfunction

They look like surface mount resistors I forget the size (602 rings a bell) but i've got a duff set of temp sensors here - i'll test mine and get back to you all as to what i find.

Cheers

Chris

Mik
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Re: Temperature sensor malfunction

Thanks for your replies, guys!

Does anyone know where the "Ambient temperature sensor" is located in a VX-1?

I know the 12 battery sensors are pain to reach....

This information may be used entirely at your own risk.

There is always a way if there is no other way!

ofx210p
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Re: Temperature sensor malfunction

no idea where the ambient one is however having checked over the 'faulty' temp sensor loom, i've tested the resistance of the temp sensors and pretty certain they are 0805 smd ntc 10k thermistors.


http://uk.rs-online.com/web/p/thermistor/7062727/
is an example of them 10k Ohm at25 degrees.
Resistance goes down as temperature goes up. (Is that a negative temperature coefficient lol... I think it is ) Its been 5 yrs since i played with electronics in a big way

Hope this helps

X Vectrix
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Re: Temperature sensor malfunction

Mik
The ambient sensors are on the small PCBs from which all the sensor wires originate.

Mik
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Re: Temperature sensor malfunction

Mik
The ambient sensors are on the small PCBs from which all the sensor wires originate.

Thanks, X Vectrix, I'll have a closer look at my spare battery sensor board to see which one it is. Maybe I can fix this - nice challenge trying to solder SMT components....

This information may be used entirely at your own risk.

There is always a way if there is no other way!

X Vectrix
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Re: Temperature sensor malfunction

Its labeled VR1. Between C8 (2 pins) and U5 (3 pin device). I tried to include a picture but cant figure out how.

Mik
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Re: Temperature sensor malfunction

Its labeled VR1. Between C8 (2 pins) and U5 (3 pin device). I tried to include a picture but cant figure out how.

Thanks again!

It can be seen in this photo (click to enlarge):
Photobucket

Would replacing this VR1 likely fix the problem of the erratically jumping ambient temperature values?

And how do I decide which board (front or back battery board) to tackle first?

This information may be used entirely at your own risk.

There is always a way if there is no other way!

X Vectrix
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Re: Temperature sensor malfunction

Mik
Have you already taken it out in this pix? Or is it missing?

Mik
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Re: Temperature sensor malfunction

Mik
Have you already taken it out in this pix? Or is it missing?

I must have had tomatoes on my eyes when I looked at the picture - YES, it's missing! I thought I saw it.....

The picture was taken years ago when I took the battery apart to analyze what was going wrong with it. This temp sensor is now back in the "Vectux".

The VR1 location does not look like it has fallen off, maybe it had never been installed in the first place?

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Mik
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Re: Temperature sensor malfunction
Mik
Have you already taken it out in this pix? Or is it missing?

I must have had tomatoes on my eyes when I looked at the picture - YES, it's missing! I thought I saw it.....

The picture was taken years ago when I took the battery apart to analyze what was going wrong with it. This temp sensor is now back in the "Vectux".

The VR1 location does not look like it has fallen off, maybe it had never been installed in the first place?

I checked the temp sensor boards that came with the VX-1 NiMH battery that I bought off Antiscab: The VR1 locations on both front and rear battery boards are empty!

Now what???

This information may be used entirely at your own risk.

There is always a way if there is no other way!

X Vectrix
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Re: Temperature sensor malfunction

Sorry Mik, I am completely screwing you up on this. I havnt looked at these boards in a while. U5 is the absolute ambient temp sensor. It has a linear V/degC output. VR1 is the calibration thermistor. The calibration thermistor was placed right next to the absolute sensor so that all the sensors on the cells could be calibrated against a known value. However, the calibration sensor was never used, and not installed on old boards. Later they were installed. The SW does not use any information from the calibration. Are you sure its the ambient temp that is jumping around and not the calibration value?

Mik
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Re: Temperature sensor malfunction

Sorry Mik, I am completely screwing you up on this. I havnt looked at these boards in a while. U5 is the absolute ambient temp sensor. It has a linear V/degC output. VR1 is the calibration thermistor. The calibration thermistor was placed right next to the absolute sensor so that all the sensors on the cells could be calibrated against a known value. However, the calibration sensor was never used, and not installed on old boards. Later they were installed. The SW does not use any information from the calibration. Are you sure its the ambient temp that is jumping around and not the calibration value?

A three-legged temp sensor? That might explain why it can behave so erratically, some IC going mad....

The calibration value is relatively stable, but the ambient temp 4D jumps around wildly. Have seen temps as high as 90degC now...

This information may be used entirely at your own risk.

There is always a way if there is no other way!

Kocho
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Re: Temperature sensor malfunction

Let me revive this thread. So, are the Calibration sensors used? On my "new" VX-1 one of the two calibration temp values that shows first in scooter diag screen always reads something like 1.7C degrees. Is this something to worry about/fix?

Also, does someone have a schematic of which module temp sensor is located where in the battery packs?

Edit: attached is what mine looks like:
Temp sensors.JPG

P.S. What genius designed the add image function here?!? I figured it out, but man - is it unusual...

Thanks!

Sorry Mik, I am completely screwing you up on this. I havnt looked at these boards in a while. U5 is the absolute ambient temp sensor. It has a linear V/degC output. VR1 is the calibration thermistor. The calibration thermistor was placed right next to the absolute sensor so that all the sensors on the cells could be calibrated against a known value. However, the calibration sensor was never used, and not installed on old boards. Later they were installed. The SW does not use any information from the calibration. Are you sure its the ambient temp that is jumping around and not the calibration value?

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