DJI Wookong M PMU ERR

[aerialindo]

Hi all, I have also added a new post on this topic, but no replies so jumping on the end of this one. My PMU is sending inaccurate measurements when batteries are under load. It is showing about 1.5 volts less that what the battery actually is (have taken readings from a battery checker thats plugged into the balance cable when hovering at the same time.

When there is no load - the PMU reading is accurate.

This of course is concerning to me. Second level of protection comes in just after a few minutes of flying when actually there is still lots of power left in the batteries.

Any ideas or pointers are much appreciated here!

Thanks,

Aaron

 

[Tahoe Ed]

Hi all, I have also added a new post on this topic, but no replies so jumping on the end of this one. My PMU is sending inaccurate measurements when batteries are under load. It is showing about 1.5 volts less that what the battery actually is (have taken readings from a battery checker thats plugged into the balance cable when hovering at the same time.

When there is no load - the PMU reading is accurate.

This of course is concerning to me. Second level of protection comes in just after a few minutes of flying when actually there is still lots of power left in the batteries.

Any ideas or pointers are much appreciated here!

Thanks,

Aaron

You may have high internal resistance so the voltage under load and that at rest are different. 1.5v is high but I have seen as high as .9v. I would suggest a voltage monitor with logging. That will give you the information that you need to see what is going on.

 

[aerialindo]

Like an on board voltage logger? I'll check it out. Living in Bali makes it hard to get special things though! We have been doing logging tests manually all day and can see that it's definitely the PMU error. Question is, how can this be fixed.... My dealer is confused too... Maybe best I send an email to DJI support. They have been helpful in the past...