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Mavic Air 2 - Extended capacity battery mod - 7350mAh - Not my work

lee82gx

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I suppose there is limited English reviews of this mod.

In Malaysia and several countries in South East Asia, some skilled modders have access to raw DJI battery cells (through China).

By combining this with the existing cells you can have 3S2P configurations, for around US$70 you can modify your existing battery pack.

Screenshot_20200814-120846_Video Player.jpg

Here is how it performs:

Hover to 0 - 43:42s
Short flight to 9% (Auto Landing begins), no cancellation allowed - 40:28s (I spent a good 3 mins on the ground to check everything and lock gps)

Dat files to check the flight parameters: Mavic_air_2_Extended_battery_Flight_test_7350mAh.PNG
A few notes - Battery capacity was reprogrammed to 7350mAh, and so it is intelligent. You can see the remaining cap in mAh, and also % tracking it closely. RTH time is also accurate. But the dat file is somehow truncated in this file and it only records up to 1840s. Another roughly 10mins of flight was not recorded somehow...

Battery current is around 10A, flying very steadily and was around 2-5m/s speed. Motor speed on Front ard 7200rpm. ESC temp "~630", I assume is 63C. After land, the motor covers, arms, motors do not feel too hot to touch. They are definitely warmer than normal. As comparison, I previously tested Mavic Pro with extended batteries and they are so much warmer.

Mavic_air_2_normal_battery_Flight_test_3500mAh.PNG

I just compare a normal standard battery in a normal flight.
Battery current is around 6.6A, flying very steadily and was very low speed. Motor speed on Front ard 6400rpm. ESC temp "~540", I assume is 54C. After land, the motor covers, arms, motors feels only slightly warm. Battery temp here is 47C


Based on the increase in load 10A vs 6.6A, the flight times are pretty makes sense. 7.35Ah/10A=44min. 3.5Ah/6.6A=32min

Lastly the weight is 390g total. So if you have a payload of about 150g, then the flight time will decrease to 21mins.
 

Nonprophet

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Why? Seriously. Why risk damage to a $1,000 drone and voiding your warranty when we average 25 minutes per flight flying it the way they were intended......
 
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lee82gx

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Why? Seriously. Why risk damage to a $1,000 drone and voiding your warranty when we average 25 minutes per flight flying it the way they were intended......
Hello, i detailed a long post with the intention talking about risk management to my own drone, I believe it was an acceptable level. Many of the posts in this subsection of the forum voids warranty and present some form of additional risk or another.
 
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gb160

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Why? Seriously. Why risk damage to a $1,000 drone and voiding your warranty when we average 25 minutes per flight flying it the way they were intended......
Because some of us just want to see the world burn.
 
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lee82gx

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Actually, with the new task list 45 point hyperlapse. I plan to do some aerial mapping and surveying. If you tried it, a 2x20min flights with waypoints stitched in between is a pain in butt to map. That was my original intention.

With a 40min battery, you can do a much larger area.
 
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GadgetGuy

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Actually, with the new task list 45 point hyperlapse. I plan to do some aerial mapping and surveying. If you tried it, a 2x20min flights with waypoints stitched in between is a pain in butt to map. That was my original intention.

With a 40min battery, you can do a much larger area.
I believe you can now pause and resume a waypoint mission while swapping batteries in between. No need for a continuous flight any more.
 

Dr. Bill 1969

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I suppose there is limited English reviews of this mod.

In Malaysia and several countries in South East Asia, some skilled modders have access to raw DJI battery cells (through China).

By combining this with the existing cells you can have 3S2P configurations, for around US$70 you can modify your existing battery pack.

View attachment 110572

Here is how it performs:

Hover to 0 - 43:42s
Short flight to 9% (Auto Landing begins), no cancellation allowed - 40:28s (I spent a good 3 mins on the ground to check everything and lock gps)

Dat files to check the flight parameters: View attachment 110576
A few notes - Battery capacity was reprogrammed to 7350mAh, and so it is intelligent. You can see the remaining cap in mAh, and also % tracking it closely. RTH time is also accurate. But the dat file is somehow truncated in this file and it only records up to 1840s. Another roughly 10mins of flight was not recorded somehow...

Battery current is around 10A, flying very steadily and was around 2-5m/s speed. Motor speed on Front ard 7200rpm. ESC temp "~630", I assume is 63C. After land, the motor covers, arms, motors do not feel too hot to touch. They are definitely warmer than normal. As comparison, I previously tested Mavic Pro with extended batteries and they are so much warmer.

View attachment 110578

I just compare a normal standard battery in a normal flight.
Battery current is around 6.6A, flying very steadily and was very low speed. Motor speed on Front ard 6400rpm. ESC temp "~540", I assume is 54C. After land, the motor covers, arms, motors feels only slightly warm. Battery temp here is 47C


Based on the increase in load 10A vs 6.6A, the flight times are pretty makes sense. 7.35Ah/10A=44min. 3.5Ah/6.6A=32min

Lastly the weight is 390g total. So if you have a payload of about 150g, then the flight time will decrease to 21mins.

Neat modification. As to the naysayers, there's no substitute for more lingertime.
 

lupedj4

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QUestion, How do you program the BMS (Or Smart battery controller) to think that the battery has a higher capacity and what program you used to reprogrammed? cause i did that to mine drone but as if it loosing flight time and when it hit 0, i still have power to fly the drone IMG_1043.jpeg
 

lee82gx

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A few things before I explain further.
1. It’s not my work, as stated in title.
1.1 whatever I say next is based on my theory and not practice...
2. Battery communicates via SMB protocol ( system management bus).
You need to have a Ev2300 or compatible board, with drivers to read And decode the SMB data. It consist of SDA, SDC and GND pins. Sourcing for this is not difficult if you are willing to pay.
3. To read or write the PROM on the BMS you also need developer level access, which is possible if you have UBRT with read write access, or BQ studio with developer access to unseal or unlock the ROM for reprogram. Both can allow you to rewrite the internal capacity to any other value you desire. I am neither and trying to source for this seems expensive
4. Your hardware hack looks neat. But you have to do proper 3S2P for a good function. From the pictures you look like just wired 3S1P + 3S1P, whereby the you paralleled 2 11.4V packs. That can also work but the packs are not always in good voltage balance. One pack may be higher than the other.
5. Of course if you do 4, the BMS will never charge properly or even if you manage to set it to a higher cap, it does not discharge properly along with the capacity curve.
For some years, your method of strapping a parallel pack is the normal way to boost capacity, so I’m not sure why it’s not working in your case. Are you sure you wired correctly?

you need to charge the extra pack by yourself externally with a RC charger, by balance charging preferably. Then with your fully charged original battery on the drone and powered up, only after that you attach the external pack to the Drone’s + and - points or to the battery’s output terminal. It should work in extending the extending the flight time. the voltage curve should drop very slowly as intended and flight time should increase, but I’ve not tried this with Mavic Air 2. Last I tried was with a Mavic pro 1.
 
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