Mavic Pro Motor Mod

lolo780 · Jun 4, 2018

When I've run 4s I just used the battery board to show total pack voltage on screen. I didn't connect any balance leads to individual cells.

What would be really nice is an OSD hack to display battery data from aftermarket sensors.

Lipo packs are ok to charge to 4.35v, just keep an eye on them.

beanbubba · Jun 4, 2018

beanbubba said:
Ugg, I think we may eventually burn out the battery controller with the increased voltage. Just did a 10 min hover and the board was too hot to touch (and the LEDs were much brighter than on 3s). Not sure how to engineer around this one.

Well, maybe not so bad. I didn't realize the battery controller will work just fine using the balance cable only. The LEDs are back to normal brightness and I think this may work. Gonna hover now til she comes down.

I am wondering if setting the battery in assistant fixes the percentages display.

I am currently at 3.76 volts and it shows 81%. Can someone with 4s experience calculate if this percentage is close or not?

beanbubba · Jun 4, 2018

One nugget of knowledge, these new batteries put a lot of weight forward past the center of gravity. At takeoff, it almost flips over forward until the motors spin up to speed. But once in the air, no more issues related to this.

Chazz, is this similar to what u saw?

lolo780 · Jun 4, 2018

The percentage should be roughly the same, but voltage drop should be less for a given power level due to lower current and resistive losses.

A nice way to graph your particular setup is show battery voltage vs time in Csviewer and hover until critical auto land kicks in.

beanbubba · Jun 4, 2018

chazz said:
you didn't buy lihv which is what i didn't want to tell you yet. you got the 14,8V instead of 15.2V. You can charge that battery to 16.8V. 4.2V per cell. Charge it using the normal lipo setting on your charger. Don't run it down past 3V per cell i hear that will destroy the battery. Fly around with it and see how long of light time you get with it but don't stray too far away from home. Its up to you to make sure you land before 3V it wont autoland. (or at least mine didnt) Percentage readout is worthless only go by single cell voltage. It will display the lowest cell on the front page of djigo.

I am in a hover test right now and all the battery indicators were in the green (but percentage stays at what is was at power on).

But at 3.62 volts the battery indicators went red.

Can anyone decipher this and what triggered the red status?

Should I land right at 3.00 volts?

chazz · Jun 4, 2018

you have you low voltage set to 3.7 and critical set to 3.5 in assistant so things may happen because of that.

beanbubba · Jun 4, 2018

beanbubba said:
I am in a hover test right now and all the battery indicators were in the green (but percentage stays at what is was at power on).

But at 3.62 volts the battery indicators went red.

Can anyone decipher this and what triggered the red status?

Should I land right at 3.00 volts?

View attachment 39435

At 3.29 volts, forced auto landing engaged. I only fought it for 10 seconds or so and then landed. I think the assistant battery config is being used for the calculations. And the percentage indicator is bogus and not part of the equation (I think).

chazz · Jun 4, 2018

beanbubba said:
I am in a hover test right now and all the battery indicators were in the green (but percentage stays at what is was at power on).

But at 3.62 volts the battery indicators went red.

Can anyone decipher this and what triggered the red status?

Should I land right at 3.00 volts?

View attachment 39435

i would stop a 3v if your testing flight time

lolo780 · Jun 4, 2018

Is your low battery set to 14.8v? Normal for the voltage to turn red. I always set those to the minimum values.

chazz · Jun 4, 2018

beanbubba said:
At 3.29 volts, forced auto landing engaged. I only fought it for 10 seconds or so and then landed. I think the assistant battery config is being used for the calculations. And the percentage indicator is bogus and not part of the equation (I think).

3.29V is safe.

chazz · Jun 4, 2018

beanbubba said:
One nugget of knowledge, these new batteries put a lot of weight forward past the center of gravity. At takeoff, it almost flips over forward until the motors spin up to speed. But once in the air, no more issues related to this.

Chazz, is this similar to what u saw?

yes but mine stopped being able to pick the front end up

chazz · Jun 4, 2018

i never set mine to 4s so idont know how that affects things. I don't think mine ever hit auto land with a 4s. but like i said i have voltages changed in the fw

beanbubba · Jun 4, 2018

chazz said:
yes but mine stopped being able to pick the front end up

ok, then we are seeing the same thing. Try to place center of gravity back as much as possible.

beanbubba · Jun 4, 2018

Blazing a trail... my bird no longer has valid logs. after each flight it lists a log for the flight, but it is only a meg or two and csviwer says its corrupted when attempting to open. I haven't a clue how to debug this one

lolo780 · Jun 4, 2018

beanbubba said:
Blazing a trail... my bird no longer has valid logs. after each flight it lists a log for the flight, but it is only a meg or two and csviwer says its corrupted when attempting to open. I haven't a clue how to debug this one

Install an SD card and .700 flight control?

beanbubba · Jun 4, 2018

lolo780 said:
Install an SD card and .700 flight control?

OK, figured out the log issue. There is a very specific startup sequence using the 3rd party battery controller. If you do not startup correctly, no logs. I will try to document this.

beanbubba · Jun 4, 2018

Did a hover test with 3xMS5200 and everything was in the green until 6 minutes into the flight.

Log files here: drone-share-temp

Then received a controller and barometer error:

About a minute later the bird fell from the sky

Right after the crash I felt the batteries, bottom plate, and all four motors. Everything was barely warm EXCEPT for the front right motor which I think gave me a minor 2nd degree burn after grabbing it. It had started to melt through the rotor arm, but only warped it to that point.

Video of crash:

lolo780 · Jun 4, 2018

beanbubba said:
OK, figured out the log issue. There is a very specific startup sequence using the 3rd party battery controller. If you do not startup correctly, no logs. I will try to document this.

The main battery can shut down some functions via serial data I think. I run my DJI batteries manually jumped to be always on in flight, but I noticed if you push the off sequence the bird partially shuts off, although the ESCs stay on.

beanbubba · Jun 4, 2018

lolo780 said:
The main battery can shut down some functions via serial data I think. I run my DJI batteries manually jumped to be always on in flight, but I noticed if you push the off sequence the bird partially shuts off, although the ESCs stay on.

110% concur from my observations.