Mavic Pro Motor Mod

[chazz]

My 4s 5200lihv weighs 440grms

 

[beanbubba]

My 4s 5200lihv weighs 440grms

I bet all the packaging weighs at least 25-30 grams.

 

[beanbubba]

I bet all the packaging weighs at least 25-30 grams.

Is yours a 4s/2p or 4s/3p ?

 

[chazz]

4s2p.... A ms5200 3s i think is 3s2p which means each cell is 2600mah. It looks like you added a cell in parallel so that would make that a 4s3p 7800mah.

 

[beanbubba]

4s2p.... A ms5200 3s i think is 3s2p which means each cell is 2600mah. It looks like you added a cell in parallel so that would make that a 4s3p 7800mah.

Please skool me because I am new to battery tech. How does making two 5200/3s2p to a 4s/3p end up at 7800mAh ??

Why is it not 10,400?

 

[beanbubba]

20 sec hover and got a hard landing. I actually saw the left rear motor stop. There are some weird things in this pic. Left rear motor 100pwm with 0 speed. right front 0 current,10pwm and 6073 rpm. Are these just delays in signals ya think?

FLY545.DAT


View attachment 39503

I was going to say hover to crash but after i saw pieces flying in beanbubba's crash i changed it to hard landing.

In my crash it appeared that my front/right motor stopped in person in real time. And I still have a finger burn from that motor

 

[BudWalker]

20 sec hover and got a hard landing. I actually saw the left rear motor stop. There are some weird things in this pic. Left rear motor 100pwm with 0 speed. right front 0 current,10pwm and 6073 rpm. Are these just delays in signals ya think?

FLY545.DAT


View attachment 39503

I was going to say hover to crash but after i saw pieces flying in beanbubba's crash i changed it to hard landing.

The gap is caused by an abrupt power loss.

With a normal battery set up this is seen when the battery is removed without first turning it off. The abrupt power loss results in the .DAT file not being closed properly and the end of the .DAT is actually the remnants from some previous .DAT. In this case those remnants came from a flight that occurred 2018-04-20 13:49:29 GMT. You'll notice that when the cursor is moved past 53 secs it's the values at 480 secs that are being reported. I.e., the trace lines shown between 53 secs and 480 secs aren't actually values, they are just the interpolation between the end points.

Is this a Mavic Pro Platinum? If so, that might explain the unrealistic current values. The Platinum uses FOC for motor control. @lolo780 knows more about this.

 

[beanbubba]

Please skool me because I am new to battery tech. How does making two 5200/3s2p to a 4s/3p end up at 7800mAh ??

Why is it not 10,400?

View attachment 39523

OK, I RTFM'd and "think" I understand the math now:

Original 3s2p = 11.4v @ 5200 mAh

11.4 / 3 = 3.8 (Series = sum cell V)
5200 / 2 = 2600 (Parallel = sum cell mAh)
6 Cells @ 3.8v, 2600 mAh, each


New 4s3p = 15.2v @ 7800 mAh

12 Cells @ 3.8v, 2600 mAh, each
3.8 * 4 = 15.2 (Series = sum cell V)
2600 * 3 = 7800 (Parallel = sum cell mAh)


But I must have messed up the wiring because my charger thinks its a 1s and gets a high voltage error.

Does this look right for a 4s3p ?

 

[beanbubba]

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 doing a hover test now with an LiHv. Whats the lowest voltage I can run down to before harming the battery?

This is new newly minted LiHv 7800 mAh 4s3p:

 

[chazz]

OK, I RTFM'd and "think" I understand the math now:

Original 3s2p = 11.4v @ 5200 mAh

11.4 / 3 = 3.8 (Series = sum cell V)
5200 / 2 = 2600 (Parallel = sum cell mAh)
6 Cells @ 3.8v, 2600 mAh, each


New 4s3p = 15.2v @ 7800 mAh

12 Cells @ 3.8v, 2600 mAh, each
3.8 * 4 = 15.2 (Series = sum cell V)
2600 * 3 = 7800 (Parallel = sum cell mAh)


But I must have messed up the wiring because my charger thinks its a 1s and gets a high voltage error.

Does this look right for a 4s3p ?

View attachment 39556

I'm glad you figured it out because i suck at splaining stuff

your balance lead looks wrong to me. look here R/C Calculations to see if you can figure it out.

 

[beanbubba]

I'm glad you figured it out because i suck at splaining stuff

your balance lead looks wrong to me. look here R/C Calculations to see if you can figure it out.

Yep, I had the middle leads out of order. Fixed that and all is working now. I have the bird in the air right now for a hover test but don't know how low I can go on LiHv voltage.

 

[chazz]

I am doing a hover test now with an LiHv. Whats the lowest voltage I can run down to before harming the battery?

This is new newly minted LiHv 7800 mAh 4s3p:

View attachment 39587

under 3V per cell and supposedly it's toast.

 

[beanbubba]

under 3V per cell and supposedly it's toast.

OK, you told me that for Lipo, its the same for LiHv ??

 

[chazz]

same

 

[chazz]

The gap is caused by an abrupt power loss.
View attachment 39535
With a normal battery set up this is seen when the battery is removed without first turning it off. The abrupt power loss results in the .DAT file not being closed properly and the end of the .DAT is actually the remnants from some previous .DAT. In this case those remnants came from a flight that occurred 2018-04-20 13:49:29 GMT. You'll notice that when the cursor is moved past 53 secs it's the values at 480 secs that are being reported. I.e., the trace lines shown between 53 secs and 480 secs aren't actually values, they are just the interpolation between the end points.

Is this a Mavic Pro Platinum? If so, that might explain the unrealistic current values. The Platinum uses FOC for motor control. @lolo780 knows more about this.

Thanks Budwalker. i did pull the battery while powered. After a crash within the first 20sec of flight anything goes. Its not a platinum but I think the readings are messed up because of how heavily modded this thing is and the bird is just plain confused.

 

[beanbubba]

I think we are narrowing the safe range of this mod.

Note that voltage dropped super rapidly when it hit 3.3v and forced landing kicked in. I held it up for 20-30 seconds then landed when it quickly dropped below 3v (hope I did not kill the battery).

Good news! Zero errors during the hover test, all four motors and battery were barely warm after the flight.

This is a new baseline I think we can call a win that out performs the factory mavic. Of course I need to repeat this same test many times, but this is the only non issue test of the mod I have personally witnessed.

Mod summary:

p3 gen2 motors
extended rotor arms
7800mAh LiHv 4s3p
after market battery controller (minus factory battery cells)
Almost 36 minutes hover flight time
AUW 1383 grams

 

[chazz]

I am doing a hover test now with an LiHv. Whats the lowest voltage I can run down to before harming the battery?

This is new newly minted LiHv 7800 mAh 4s3p:

View attachment 39587

Dude! i have to say that's one nice battery! Us P3ers would love to have that!

 

[beanbubba]

I think we are narrowing the safe range of this mod.

Note that voltage dropped super rapidly when it hit 3.3v and forced landing kicked in. I held it up for 20-30 seconds then landed when it quickly dropped below 3v (hope I did not kill the battery).

Good news! Zero errors during the hover test, all four motors and battery were barely warm after the flight.

This is a new baseline I think we can call a win that out performs the factory mavic. Of course I need to repeat this same test many times, but this is the only non issue test of the mod I have personally witnessed.

Mod summary:

p3 gen2 motors
extended rotor arms
7800mAh LiHv 4s3p
after market battery controller (minus factory battery cells)
Almost 36 minutes hover flight time
AUW 1383 grams

View attachment 39588

But no logs on this flight. Will have to figure this out and what I did to stop the logs...

 

[BudWalker]

But no logs on this flight. Will have to figure this out and what I did to stop the logs...

This might be relevant
Keeping .DATs on the Mavic Pro accessible

 

[beanbubba]

This might be relevant
Keeping .DATs on the Mavic Pro accessible

Interesting... this is a brand new bird with right about 20 flights.