Mavic Pro Motor Mod

Paulo Lobo · Apr 25, 2019

Hi,

Think with me please,

1 - We have a dji mavic, and we use original battery, it can fly 20 minutes...

2 - We take another original battery and insert it on the drone with tape, how much time will the drone fly with two battery on it ?

So i want someone to test this and tell me.

Thanks

Paulo

AnzacJack · Apr 25, 2019

Maybe 28 mins? Just guessing

Paulo Lobo · Apr 26, 2019

No No,

Im saying a second battery with no connection to the drone !
How much is reduced the time of flight ?

surfbird · Apr 27, 2019

I did some tests with MPP hovering with different added weight to the normal setup with one dji battery.
Hovering indoors at 20c. When adding weight the motors can be quite hot so hovering for a long time isn't good.

I actually squeezed 42minutes hovering out if two stripped dji battery pack, which was overcharged to 4.40V. Run them a little bit to low though, but they seems to handle it quite well.
Now I'm trying 4-dji packs and I'm amazed how long flighttime you can have. My goal is to break 60minutes flying with 8m/s speed.
When flying with 8m/s the power drain is 160-170w. Dji props beat all other props by far.

When overcharged to 4.40V my charger show 4400mAh. I don't know if it's accurate, but it seems to sum up with the power drain.

One striped dji pack weight 200grams.

Weight	Tot weight	Power	weight/power
240	734	96	7.645833333
334	828	116	7.137931034
428	922	131	7.038167939
522	1016	150	6.773333333
616	1110	170	6.529411765
663	1157	182	6.357142857
710	1204	194	6.206185567
757	1251	204	6.132352941
804	1298	219	5.926940639

Paulo Lobo · Apr 27, 2019

Nice test you got there.

But all are doing the things on one way, and i have a idea to do another way.

Let see if my english explain you !

I can build a electronic board to connect to the drone in one side and on the other side it takes the connections of two battery, when the drone is flying it works only with one battery, when this battery is almost empty the electronic board switchs to the other battery, so there will be no connections bettwen the two batterys.

This is my idea, so this is why im asking people to make a simple test, how long the mavic will fly with the two batterys on it but only one connected !!

Understand ?

Texas Mavic · Apr 27, 2019

Yes, you are building a switching interface that switches to the second battery when the first is low. Correct?

Texas Mavic · Apr 27, 2019

surfbird said:
I did some tests with MPP hovering with different added weight to the normal setup with one dji battery.
Hovering indoors at 20c. When adding weight the motors can be quite hot so hovering for a long time isn't good.

I actually squeezed 42minutes hovering out if two stripped dji battery pack, which was overcharged to 4.40V. Run them a little bit to low though, but they seems to handle it quite well.
Now I'm trying 4-dji packs and I'm amazed how long flighttime you can have. My goal is to break 60minutes flying with 8m/s speed.
When flying with 8m/s the power drain is 160-170w. Dji props beat all other props by far.

When overcharged to 4.40V my charger show 4400mAh. I don't know if it's accurate, but it seems to sum up with the power drain.

One striped dji pack weight 200grams.

Weight Tot weight Power weight/power
240
734
96
7.645833333
334
828
116
7.137931034
428
922
131
7.038167939
522
1016
150
6.773333333
616
1110
170
6.529411765
663
1157
182
6.357142857
710
1204
194
6.206185567
757
1251
204
6.132352941
804
1298
219
5.926940639

I am considering splitting the 3 cells, and having one on each side
Like dual mounted, and one cell on top. Does this sound feasible?

Paulo Lobo · Apr 27, 2019

Yes that will work, the cells splitting !

About the

TexasFlytography said:
Yes, you are building a switching interface that switches to the second battery when the first is low. Correct?

Thats it, but for now i need to know how much time will the mavic fly that way.

Paulo Lobo · Apr 27, 2019

TexasFlytography said:
I am considering splitting the 3 cells, and having one on each side
Like dual mounted, and one cell on top. Does this sound feasible?

Yes, it will be a good idea !

Texas Mavic · Apr 27, 2019

Paulo Lobo said:
Yes that will work, the cells splitting !

About the

Thats it, but for now i need to know how much time will the mavic fly that way.

I’ll have an answer for you shortly

Texas Mavic · Apr 27, 2019

Paulo Lobo said:
Nice test you got there.

But all are doing the things on one way, and i have a idea to do another way.

Let see if my english explain you !

I can build a electronic board to connect to the drone in one side and on the other side it takes the connections of two battery, when the drone is flying it works only with one battery, when this battery is almost empty the electronic board switchs to the other battery, so there will be no connections bettwen the two batterys.

This is my idea, so this is why im asking people to make a simple test, how long the mavic will fly with the two batterys on it but only one connected !!

Understand ?

I have tried this inadvertently. This was the result. Extra 200gram top mounted payload. Not plugged in. Hope it helps.

Paulo Lobo · Apr 27, 2019

TexasFlytography said:
I have tried this inadvertently. This was the result. Extra 200gram top mounted payload. Not plugged in. Hope it helps.

So that kind of flight, i think was hoover has give 25 minutes with extra 200gram on top not plugged in, and with no extra 200gram doing the same kind of flight ??

Paulo Lobo · Apr 27, 2019

From what i see with two original battery you can do 50 minutes with a electronic board controling the switch from one bat to another, doing that kind of flight, right ??

Texas Mavic · Apr 27, 2019

Sounds feasible to me

Texas Mavic · Apr 28, 2019

What kinda switch you have in mind?

surfbird · Apr 28, 2019

I expect to get 60min plus with this setup. Flying slowly in 8m/s
4 dji packs. Flies like a dream. Made some vents for cooling the motors.

I dont understand the advantage of having a switch? Why is that?

Texas Mavic · Apr 28, 2019

surfbird said:
I expect to get 60min plus with this setup. Flying slowly in 8m/s
4 dji packs. Flies like a dream. Made some vents for cooling the motors.

I dont understand the advantage of having a switch? Why is that?
View attachment 70922

Are you about to test that? Basically he is talking about making a switch that switches to a 2nd battery after the 1st has gotten low.

Texas Mavic · Apr 28, 2019

The advantage of that would be whatever flight time is on the 1st battery, plus the second after a specified level, and you get whatever the two batteries flight time is. I am very interested in what is to come from your test there.

surfbird · Apr 29, 2019

TexasFlytography said:
Are you about to test that? Basically he is talking about making a switch that switches to a 2nd battery after the 1st has gotten low.

Yepp I've already tested, but I have only been flying max 20minutes. I don't want to tear to much on the batteries, so instead I check with the charger how many mAh charge it can take and try to estimate the complete flight time would be. I'm using a balance charger that displays how many mAh that been charged.

According to that, the flightime would be 67minutes, but I might done something wrong

. For the moment I'm trying to find the most effecient flying speed and props. Then I will do the 'real' run that hopefully will be more than 60minutes!

Today I did a test with 5

dji batteries. Not effecient at all. 230W as lowest. Very slow climb, but the motors were not running hot, seems like the venting holes works. Total weight 1534gram. Funny enough it was handling very well, and the forward speed wasn't bad 12-13m/s at constant altitude.