When a 14-cell battery is monitored by the power module, the battery level is incorrect

ArduCopter Copter 4.5
1

Hello, everyone!
I am having trouble with a strange phenomenon that I have encountered since yesterday.

What is the remaining % of the battery displayed in reference to?
I recently took over a project on a large aircraft and after flying for a while, the battery remaining in QGC remained at 100% and did not change.

I thought it was odd, so I looked at how the battery % remaining would change in two cases

  1. three 14-cell HV batteries monitored with MAUCH’s Power Monitor
    This is completely correct wiring.
  2. two 14-cell HV batteries monitored with CUAV’s Digital CAN PMU SE
    This is correct for voltage, but monitors the current flowing to the receiver. The person who connected them is not very familiar with electricity.

The test was done using a stabilized power supply and verified that the battery voltage is correct in both cases.
When the voltage was varied from 60V to 50V in these two cases, the remaining battery life was displayed as almost 100%.

We did some experiments here.

  1. I checked the voltage at which the remaining battery percentage begins to decrease.
    This was 52V.
  2. Using the MAUCH Power Monitor, I set the battery capacity to 200 and checked the remaining % change.
    It decreased in order from 100% to 0%.

If anyone has the same problem and has solved it, please let me know the solution.
Also, if you know of any places I should check, please let me know.

Best regards

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2

My apologies.
I see that the issue regarding the battery monitor has been raised many times in the past.

It is true that the most “correct” way to measure the current is to measure it in terms of current.

I was wondering if you could think of one for aircraft that are not able to detect the current correctly, as in my case, or are only equipped with a voltmeter.

It would be helpful to have an approximate % indication based on voltage as an option that can be selected at the user’s risk.

Thank you.

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