Incorrect voltage shown in QGC and Terlemetry

[DUKE40]

Hi,

I have an AQ with DIMU and FW 7.0 B1756 with HoTT Telem3try enabled.
My 3S Lipo shows a voltage of 12.34V, but in the QGC and the Telemetry I have only 0.8V, I am sure I need to change some setting, but I could not find which one in the documentation. Could yomeone please point me to the setting I need to change?

[DUKE40]

The strange thing, is that when i flashed the AQ with the firmware and then performed the static calibration, the right voltage was read and displayed in QGC.
After I uploaded the params.txt file from the website (http://autoquad.org/wp-content/uploads/ ... PARAMS.zip) the voltage started to be displayed incorrectly. and now even trying to reset everything by uploading another firmware I am unable to get a correct reading of the voltage.
Anybody an idea what might be wrong and were I should look at for getting this fixed?

[kinderkram]

You don´t need the parameter file any longer. Sorry ... forgot to remove it from the Wiki. Done.
Newer versions like r395 already have the default parameters.

Maybe you first should try to use a version without HOTT enabled. If QGC reports correct values then you´ve found the cause.

[JussiH]

If its reported wrong in the QGC, then its probably a problem with the resistor divider. It doesnt sound like you have the wrong firmware loaded, since it wouldnt be that much off even if you loaded firmware for an Rev 0 board to a Rev1 boars. I actually never tried loading R1 firmware to a R0 board, but it may produce the kind of results you are seeing.

If you have a Multimeter, measure the resistance across R3 and R4. R3 should be 8.45k and R4 should be 4.7K for a Rev 1 board.

A rev 0 board will have 1.33K for R3 and 4.7K for R4

If that is ok, then check if Pin 18 on the main MCU is shorted to any adjacant pins.

Here is a pinout for main MCU:

https://www.google.dk/search?q=stm32f40 ... B728%3B666

It sounds a bit like like you could have a small solder drop or something else creating a hairline short across something in the battery sense circuit. But if you go over the above points, we should be able to work out where the error is.

[DUKE40]

Hi,

the very strange thing is everything was fine, till suddenly the voltage shown was way off.
I cannot remember having performed any soldering between the time it was OK and when it started to be incorrect.
Even in the LOG the voltage is way off.
I will check the points mentioned by Jussi above, but as I am now away from home for a week and have not the tools with me. This will only happen next weekend. Till then the quad will remain grounded for security reasons, I do not want another crash due to not everything being 100%.

[Max]

Where are you and Joerg getting firmware from the future? Latest build is #1754!

More to the point, does the problem remain if you downgrade the firmware to an earlier version?

-Max

[aBUGSworstnightmare]

[Max]

yea... I know that...

-Max

[DUKE40]

I downloaded from the Download section of the website

[DUKE40]

Downgrade is not that easy as i need HoTT Telemetry