Mavic Pro Battery Mod

[beanbubba]

And that made 13 times!!

sportbiker is a ball buster today.

 

[beanbubba]

At around 80C (175F) the magnets start to demagnetize. And at around 180C (360F) the solder starts to melt. So around 80C you start to degrade motor performance, and anything over that is just a question of what goes first. Total demagnetizing or melting wires insulation / solder points.

When the magnets start to demagnetize, it this a permanent artifact or does it return when they cool? I appreciate your knowledge on this topic, it is nice to understand every limit in detail.

 

[beanbubba]

This was my takeoff weight that we now understand auto initiates the motor ejection cooling procedure.

Whats the max takeoff weight anyone has done on a 20+ minute flight?

 

[singlag]

This was my takeoff weight that we now understand auto initiates the motor ejection cooling procedure.

Whats the max takeoff weight anyone has done on a 20+ minute flight?

View attachment 19384

View attachment 19386

according to my data, 820g extra weight will cause 5.9mah/sec, total 14000mah can fly about 39min, but motor rpm will be 9100-9200 when hover and cause overheat

my opinion is not more than 300g, so motor rpm will be about 7000, cause 3.7mah/sec
for 30min flight time with extra 300g, you will need total 6660mah, so multistar 3000mah is suggested (lipo is about 250g only)

 

[beanbubba]

according to my data, 820g extra weight will cause 5.9mah/sec, total 14000mah can fly about 39min, but motor idle rpm will be 9100-9200 and cause overheat

yea, we know that, want to know max weight without overheat.

 

[sprtbkrydr]

sportbiker is a ball buster today.

It's just my day to be nice to everyone!!

 

[digdat0]

brag all you want, Ed209 got 1300 mins stock battery, let me guess your max altitude was 20 feet[emoji41]

here's my airdata, it aint chopped .. my trick is to climb on the roof of the house with a homemade parachute from a blanket and jump.

Airdata UAV - Flight Data Analysis for Drones

This is seriously my first 20m+ stock battery flight and i put it through the paces, very happy. That battery will be used for distance

 

[beanbubba]

HEY ALL, I started a new battery thread that I need confirmation if it is valid or not. Thanks!

Mavic Factory Battery Controller Mod:
Mavic Pro Factory Battery Controller Mod

 

[chazz]

Hey Dig i'd say "way to go" but i really don't know what people are getting with the stock battery...I haven't flown mine yet ...What is the average time for a stock battery? I did charge my batt and im only getting 4.32V per cell...Is this normal?

 

[themis4]

Please mavic pilots
does anybody could help me to my issue as battery specialists ?

Battery pin connectors broken
Thank you in advance .

 

[cptlores]

When the magnets start to demagnetize, it this a permanent artifact or does it return when they cool? I appreciate your knowledge on this topic, it is nice to understand every limit in detail.

It is permanent.

 

[beanbubba]

When the magnets start to demagnetize, it this a permanent artifact or does it return when they cool? I appreciate your knowledge on this topic, it is nice to understand every limit in detail.

Thanks cptlores! If you wanted to push the limit, but attempt to be safe as possible, how close to 175F would you go during testing? Or is 175F this limit?

 

[mlash]

Hey Dig i'd say "way to go" but i really don't know what people are getting with the stock battery...I haven't flown mine yet ...What is the average time for a stock battery?

This is about average for my stock batteries. Landed at 22%. Still had some juice left.

 

[chazz]

Thanks man that seems like really good time! i hope i get the same result...

 

[CyberNate]

Thanks cptlores! If you wanted to push the limit, but attempt to be safe as possible, how close to 175F would you go during testing? Or is 175F this limit?

I doubt that the DJI motor materials are limited to 175 degrees Fahrenheit. That's fairly easily reached on a hot day. If that were true, DJI crafts would be falling out of the sky regularly due to motor failures. Anyone hear of failires due to lost magnetism on any DJI craft? Usually it's ESCs. I haven't even heard of mavic failing due to ESC issues, but on phantoms I have.

 

[cptlores]

Demagnetization is a gradual process that starts slowly. And 175F is the 'rule of thumb' temperature for when demagnetization starts. Actual temperature thresholds may vary depending on make. The more practical 'rule' in RC is that if you burn your fingers touching a motor just after a flight, then it is to hot.

There are also high temperature magnets available, but they cost more. And since the Mavic is a turnkey system where the max motor temp for normal use is well known, it does not make sense for DJI to pay extra for better magnets. So without knowing the type of magnets used, you should assume 175F to be safe.

 

[kmokong]

2 New test, DIY clip with solder to pin, seem no different

Mavic Pro with multistar 4000mah 10c Lipo with diy clip with solder
Landing : @29%
flight time: 25min 52second (2km+ range test)
Estimate-Max Flight Time : 36min
Mah/Sec : 3.499
Idle RPM : 6800rpm
Airdata UAV - Flight Data Analysis for Drones

Mavic Pro with Zippy compact 2200mah Lipo with diy clip with solder
Landing : @48%
flight time: 19min 49second (Strong wind)
Estimate-Max Flight Time : 31min
Mah/Sec : 3.14
Idle RPM : 6500rpm
Airdata UAV - Flight Data Analysis for Drones

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ei bro where you in hongkong im from hongkong also

 

[beanbubba]

Demagnetization is a gradual process that starts slowly. And 175F is the 'rule of thumb' temperature for when demagnetization starts. Actual temperature thresholds may vary depending on make. The more practical 'rule' in RC is that if you burn your fingers touching a motor just after a flight, then it is to hot.

There are also high temperature magnets available, but they cost more. And since the Mavic is a turnkey system where the max motor temp for normal use is well known, it does not make sense for DJI to pay extra for better magnets. So without knowing the type of magnets used, you should assume 175F to be safe.

Here is a better question that ultimately is what I am looking for. What is the melting temperature of the plastic used in the rotor arms? That is the real question for this situation. I guess it's time for an oven test

 

[MacIak]

Attempted 2 flights today. Straight over the drink in a bay area today to check 5200 single LiHv versus the double 3000 LiHv.
Partial success...
The 5200 flight was exciting. Made it 11400 m out and landed after almost 28 min with 3% left (yes, that gave me the buzz again. Especially because i had about 3m of land, impossible to divert). Lost a lot of juice during climb coz some high terrain in the middle made me lose signal at 25m alt and had to climb to 120.
At 90% i had 3500m distance after 4.50 mins.

The double 3000 flight started great.
At 90% (6.12 mins) 5000m out when it started raining heavily.
I decided to hit s-mode and return (entirely over open water) until connection got completely lost, no reconnect... mavic was soaked for sure so i thought it shorted and plunged into the sea. Decided to switch off remote and force RTH in case it still was airborne.
Was happy to see it was still alive. Soaked but alive. Drying now..

 

[digdat0]

At 90% (6.12 mins) 5000m out when it started raining heavily.

sounds like some good flights, great info. Saw this .. dang man,t hat must have been nerve racking! I had a similar once and flew back 10minutes in a hard rain on my p3, these things hold up. Impressed that it came back in the rain and made it back! Your rolling the dice on that water flight though. nice flying!