DJI Wookong M PMU ERR

[RC Flying]

If I use a 3 cell battery everything works fine, but if I attach a 4 cell battery the software says PMU ERR - any ideas what the problem might be?

 

[BorisS]

You have to change in the config tool from 3s to 4s are you doing that ?

Boris

 

[RC Flying]

Of course I did that. Anyway, it doesn't cause a PMU error if you don't do that, that's just for voltage monitoring. Thanks anyway though.

 

[BorisS]

As far as I remember I was getting PMU Err, when in the config tool the voltage monitor was activated and the Vsen wasn attached to X1. But since i have 2 borken PMU up to now i am not really trusting them anymore.


Boris

 

[DucktileMedia]

man this wookong sounds a real PITA! am I opening a can of worms buying this thing?

 

[BorisS]

nope and yes, this whole scene once more is nothing else then beta stuff in my eyes. But WKM DJI is certain on a higher level than MK components and all the issues they can cause you !

 

[RC Flying]

As far as I remember I was getting PMU Err, when in the config tool the voltage monitor was activated and the Vsen wasn attached to X1. But since i have 2 borken PMU up to now i am not really trusting them anymore.


Boris

I'm wondering if mine is broken too.

 

[BorisS]

which component do you have connected to the PMU canbus ?

 

[BorisS]

Thus the PMU read out the voltage of the 4s in the config tool, does it show the actual voltage ?

 

[RC Flying]

The PMU is connected as it should be, I'm not disconnecting anything - just switching from 3 cell to 4 cell. I'm not sure about the voltage reading, it doesn't seem to detect it properly with 4 cells. Once it said 16v, another time 15.1.

3 cell battery works perfectly though with no PMU ERR, regardless of what setting you choose.

 

[BorisS]

okay another simple approach sorry, but sometimes the fault is in the simple overlooked things.

you did this or ?

Power the MC by a battery and connect the MC with PC, current battery voltage will be displayed in this column.

1 If the battery voltage displayed here is different from
the voltage you measure from a voltmeter, you have to calibrate. Click the [Calibration], fill the voltage
you have just measured in the Calibration column of the dialogue box, and then click [Confirm].

 

[RC Flying]

Yes, but whether you do that or not it does not cause a PMU error. Or, to put it the other way, the PMU ERR is not caused by having the wrong voltage settings in the voltage safeguard.

 

[BorisS]

im not so sure about it. I remember switching from 4s to 5s on my CS8 and i got an PMU err, i dont know what i did anymore though and how i solved it since it was several weeks ago. Just tried to clear the steps of with you what i would have checked or probably checked when i had the same situation.

Boris

 

[RC Flying]

Ok, thanks. I just tried redoing it all again but I can't make it not do the PMU ERR. The red 2nd level warning flashes all the time too with a 4 cell battery in, even though I know it's fully charged.

I'm balancing the batteries now, just in case that is the problem.

Nope, that didn't work. If I switch off the voltage monitor it's okay, but then I don't know how long a 4 cell battery will last.

 

[chevota]

Thanks for bringing this to topic. I am having the exact same issue with a 4s setup. Looking forward to finding the problem/fix. If I come up with anything I'll be sure to post. Thanks - Scott W

 

[*****]

Had a similair issue:

1 calibrate the voltage on 4s save it

Reset the unit firmware

Connect the 5 s
Program it calibrate it
Disconnect and connect
Should work if error contact your supplier and have the part swapped

 

[RC Flying]

Thanks I tried that, didn't work. I assume where you write Connect the 5 s, you meant 4 s? And when you say Reset unit firmware you mean press update again?

The only way I can get rid of PMU ERR is to turn off voltage monitor.

 

[chevota]

I tried this as well. Still getting the PMU error :upset:

 

[BorisS]

than guys i guess its really the PMU thats faulty, write support and tell them everything you have done so they dont come back at you with the same suggestion you already got here.

 

[RC Flying]

I wrote to them last night. I'll wait a couple of days and see what happens. I just did a nice little night test flight anyway without the voltage monitor, using a lipo buzzer alarm instead.