Review of Mavic 3 double battery

[solidhouse]

Hello all,

Here is my review of the Mavic 3 double battery mod purchased on AliExpress.

Charging time takes about twice as long as the standard DJI battery. The standard DJI battery weighs 330 grams while the double battery weighs 652 grams. The double battery is quite heavy.

I did a hover test with both the original DJI and AliExpress double battery down to 9%.

The double battery lasted for 45 minutes while the original DJI battery which had 10 charge cycles on it lasted for 34 minutes.

It sounded like the motors were really straining to keep the weight of the double battery in the air. The two front motors were extremely hot to the touch when it landed.

Would I use this battery again? Probably not due to the extreme heat of the front motors. I’m actually worried now that this has caused some damage which may result in a premature motor failure.

If anyone has any questions, I’ll be happy to answer them.

Thanks,

Solidhouse

 

[Conservative Nihilist]

Hopefully, a higher-capacity battery that is close to the stock battery in weight will be developed. Every drone flier dreams of a revolution in after-market battery design for drones.

 

[old man mavic]

when a new drone is designed and developed it is a compromise between performance,size ,weight ,its all these things that impact on its capabilities and where it fits into the family lineup ,when it comes to electric battery powered aircraft of any sort ,the biggest limiting factor, impacting flight time is of course the battery ,nothing new there
when it comes to our drones weight has a bigger impact on flight time ,because of the relatively small amount of storage charge that the battery can hold, versus its ability to deliver that stored charge to the motors and all the other electronics needed to keep it in the air ,and of course all the features, that we as drone enthusiasts expect to be present,and as @solidhouse discovered just adding more storage space to a battery also almost doubled the weight of the battery ,which then impacted on the airframe and operating systems of the drone, but well done for going to the expense and risk to your drone ,to test the battery

 

[MAvic_South_Oz]

Good that people go to the trouble of testing and reporting on these sorts of mods.

To my eyes, weight / flight time analysis alone = not bothering with such a mod I guess . . .
98% more battery weight to 33% more flight time.

Add in the risk / benefit side of the equation, possibly > instability, extra motor strain / heat, less agility in flight, other (?).
Having some extra batteries at hand as needed is (to me) a much more appealing scenario.

Sure, there might be very rare flight requirements where the extra time in the air is worthwhile, but I can't really think of them off hand.

 

[GadgetGuy]

Hello all,

Here is my review of the Mavic 3 double battery mod purchased on AliExpress.

Charging time takes about twice as long as the standard DJI battery. The standard DJI battery weighs 330 grams while the double battery weighs 652 grams. The double battery is quite heavy.

I did a hover test with both the original DJI and AliExpress double battery down to 9%.

The double battery lasted for 45 minutes while the original DJI battery which had 10 charge cycles on it lasted for 34 minutes.

It sounded like the motors were really straining to keep the weight of the double battery in the air. The two front motors were extremely hot to the touch when it landed.

Would I use this battery again? Probably not due to the extreme heat of the front motors. I’m actually worried now that this has caused some damage which may result in a premature motor failure.

If anyone has any questions, I’ll be happy to answer them.

Thanks,

Solidhouse

What is the mAH of the additional battery?

There should be some weight savings on an external battery over a stock battery of the same mAH, as it doesn't need anything other than plastic wrap over the internal batteries of the pack. Some of that weight savings gets lost by adding XT60 connectors, but not much.

The photograph answers my original questions about how it was set up. It looks like a modified stock Mavic 3 battery, with the external battery connected through the back of the battery.

What you might want to try is using different external batteries, perhaps by installing an XT60 connector onto the wires coming out of the internal stock battery. Then you can experiment with different external batteries of lesser weight that might have a higher efficiency. You want the most additional mAh for the least additional weight. I suspect the battery "modder" didn't use the best external battery for this set up, as the lightest batteries for the added mAH are usually much more expensive, and he likely wanted to keep the total cost down. However, he did the hard part, which was modding the main battery with connected output leads, which you can now fine tune by trying different mAH and different weighted external batteries through XT60 connectors.

For a doubling of the mAH, you should expect a 50% increase in flight time.
Assuming the external is the same mAh as the stock battery, this is only 41%. A lighter external of the same mAh, or a same weighted one with more mAh, will be more efficient.

I also wouldn't necessarily worry about extra motor heat in a hover test with the external battery. The motors are designed for air cooling and flying will keep them much cooler. Hover tests are very inefficient.

 

[Phantomrain.org]

No need to worry about the aluminum Motors , there designed to Negotiate Extreme levels of Heat so you should be Ok as other have noted.

Like it or not were at a Technology wall of size vs power and were going to be here a very long time and Hacks are always on the Rough looking side as well.

Phantomrain.org
Gear to fly in the Rain.. and Wait For Magic Electrical Rocks in the Congo.

 

[MAvic_South_Oz]

What is the mAH of the additional battery?

There should be some weight savings on an external battery over a stock battery of the same mAH, as it doesn't need anything other than plastic wrap over the internal batteries of the pack. Some of that weight savings gets lost by adding XT60 connectors, but not much.

The photograph answers my original questions about how it was set up. It looks like a modified stock Mavic 3 battery, with the external battery connected through the back of the battery.



For a doubling of the mAH, you should expect a 50% increase in flight time.
Assuming the external is the same mAh as the stock battery, this is only 41%. A lighter external of the same mAh, or a same weighted one with more mAh, will be more efficient.

Hmm, good point, reading 'double battery' I figured it was just that.
Made sense along with the 98% increase in weight.

True, one could try good lipo soft packs, but the risks there of fire is increased if there's a crash or other damage from whatever cause.

34 mins to 45 mins is only a 33% increase in flight time.
I don't think I've ever seem anywhere near a doubling of mah to equal doubling of flight time, even with a lighter weight from less 'wrapping'.
There are many threads like this on various drone forums, people modding with extra batteries, and they never get close to double efficiency.

Look at the Mini 2 with normal and Japanese market battery.
The normal one is 2250 mah and 31 minutes flight.
Japanese battery 1065 mah and 18 minutes flight time.
(These are DJI flight time figures, just as a base comparison to each other).
The larger battery having ~ 2.1 x mah and yet just 1.7 x extra flight time.

 

[GadgetGuy]

Hmm, good point, reading 'double battery' I figured it was just that.
Made sense along with the 98% increase in weight.

True, one could try good lipo soft packs, but the risks there of fire is increased if there's a crash or other damage from whatever cause.

34 mins to 45 mins is only a 33% increase in flight time.
I don't think I've ever seem anywhere near a doubling of mah to equal doubling of flight time, even with a lighter weight from less 'wrapping'.
There are many threads like this on various drone forums, people modding with extra batteries, and they never get close to double efficiency.

Look at the Mini 2 with normal and Japanese market battery.
The normal one is 2250 mah and 31 minutes flight.
Japanese battery 1065 mah and 18 minutes flight time.
(These are DJI flight time figures, just as a base comparison to each other).
The larger battery having ~ 2.1 x mah and yet just 1.7 x extra flight time.

Not sure where you got the doubling of the mAh doubling the flight time.
I stated a 50% increase in flight time for a doubling of the mAh.
That has been my experience, and is consistent with your Mini 2 example, where DJI was able to improve upon the 50% by using a single battery, instead of piggy backing a second battery onto a stock battery, which is less efficient.
The OP only got a 33% increase in flight time from doubling the battery weight. That's pretty inefficient, and is likely due to a cheap, heavy external battery of less mAh than the stock internal battery. The external battery clearly isn't another Mavic 3 battery, when being sold together for $359. Two DJI Mavic 3 batteries alone would be $418 plus the labor and parts to do the mod, or over $500 minimum!

That's why I want to know the mAh of the external battery. We already know the weight.

 

[Meta4]

The OP only got a 33% increase in flight time from doubling the battery weight.

One small correction.
The OP tested hovering time ... not flight time.
The Mavic 3 is capable of flying for longer than it can hover.

The details from the specs are:
Max Flight Time (no wind)
46 minutes *

Max Hovering Time (no wind)
40 minutes *

* The flight time was measured in a controlled test environment. Specific test conditions are as follows: No wind, at sea level, constant flight speed of 32.4 kph, APAS off, AirSense off, camera parameters set to 1080p/24fps, video mode off, and flying from 100% battery to 0% battery. Results may vary depending on environment, usage scenario, and firmware version.

 

[GadgetGuy]

Once small correction.
The OP tested hovering time ... not flight time.
The Mavic 3 is capable of hovering for longer than it can hover.

The details from the specs are:
Max Flight Time (no wind)
46 minutes *

Max Hovering Time (no wind)
40 minutes *

* The flight time was measured in a controlled test environment. Specific test conditions are as follows: No wind, at sea level, constant flight speed of 32.4 kph, APAS off, AirSense off, camera parameters set to 1080p/24fps, video mode off, and flying from 100% battery to 0% battery. Results may vary depending on environment, usage scenario, and firmware version.

Indeed. However, one might reasonably assume that the same percentage improvement would apply to relative flight times, which should easily be able to be confirmed by flying, say in a circle around the launch point to a similar level of exhaustion on both setups, perhaps using the new Cruise Mode for consistency.

The critically unanswered question is still what the mAh of the external battery is.
Only then can we truly determine how efficient this setup is compared to other DJI battery mods that add 50% or more to the flight time by doubling the mAh.

I strongly suspect that if the battery guts of a second Mavic 3 battery were used as the external battery pack, the flight time would be 50% longer. Not only does that guarantee doubling the mAh, but it will also lighten the total weight, as the battery guts will weigh a lot less than the stock battery when removed from the casing, as opposed to the same as the stock battery in the current design, with an as yet unknown mAh, which is also likely a lot less than the stock battery.

 

[Meta4]

Indeed. However, one might reasonably assume that the same percentage improvement would apply to relative flight times, which should easily be able to be confirmed by flying, say in a circle around the launch point to a similar level of exhaustion on both setups, perhaps using the new Cruise Mode for consistency.

The critically unanswered question is still what the mAh of the external battery is.
Only then can we truly determine how efficient this setup is compared to other DJI battery mods that add 50% to the flight time by doubling the mAh.

Yes ... A large part of the battery's power is used just holding the drone in the air, with less being used for propulsion.
Give the drone a heavier battery and even more of its power is needed to keep it in the air.

 

[GadgetGuy]

Yes ... A large part of the battery's power is used just holding the drone in the air, with less being used for propulsion.
Give the drone a heavier battery and even more of its power is needed to keep it in the air.

Exactly. That's where the sweet spot has been determined to be the lightest battery that doubles the mAh of the stock battery to increase flight time by 50%. You lose 50% of the flight time from the added mAh due to carrying the extra weight added by the external battery.

 

[Cymruflyer]

Once small correction.
The OP tested hovering time ... not flight time.
The Mavic 3 is capable of hovering for longer than it can hover.

The details from the specs are:
Max Flight Time (no wind)
46 minutes *

Max Hovering Time (no wind)
40 minutes *

* The flight time was measured in a controlled test environment. Specific test conditions are as follows: No wind, at sea level, constant flight speed of 32.4 kph, APAS off, AirSense off, camera parameters set to 1080p/24fps, video mode off, and flying from 100% battery to 0% battery. Results may vary depending on environment, usage scenario, and firmware version.

I think you might want to edit one of those hovers for a flight. Have a re-read of your post, then it will make sense. We understood what you meant though.

 

[Anthony Ivory]

Exactly. That's where the sweet spot has been determined to be the lightest battery that doubles the mAh of the stock battery to increase flight time by 50%. You lose 50% of the flight time from the added mAh due to carrying the extra weight added by the external battery.

Now you have got it.
The more weight the harder the motors have to work. If you double the size of your gas tank you will not double your mileage due to the extra weight you are carrying.

 

[GadgetGuy]

Now you have got it.
The more weight the harder the motors have to work. If you double the size of your gas tank you will not double your mileage due to the extra weight you are carrying.

The gas tank analogy doesn’t quite compare because the extra gasoline weight is removed as is consumed, whereas with the drone, the extra battery weight remains constant throughout the flight, even when the extra battery is depleted. However, to the extent a doubled empty gas tank increases the weight over the stock empty gas tank, your analogy works.

 

[Anthony Ivory]

The gas tank analogy doesn’t quite compare because the extra gasoline weight is removed as is consumed, whereas with the drone, the extra battery weight remains constant throughout the flight, even when the extra battery is depleted. However, to the extent a doubled empty gas tank increases the weight over the stock empty gas tank, your analogy works.

Wow I guess I made my point : )
I’m really concerned that people want to take a risk with modified batteries that is a disaster waiting to happen.
If you haven’t flown a newer drone with about 30 minutes of flight time you will be amazed how long that is.
Batteries will always cheaper than replacing your drone due to a fire or malfunction.
Save for the newer drones and sell your old drone you will never regret it.

I think you might want to edit one of those hovers for a flight. Have a re-read of your post, then it will make sense. We understood what you meant though.

Flight time is always better than Hoover time. By the way DJI does there test indoors and quote the times until crash. We can’t afford that

 

[GadgetGuy]

Wow I guess I made my point : )
I’m really concerned that people want to take a risk with modified batteries that is a disaster waiting to happen.
If you haven’t flown a newer drone with about 30 minutes of flight time you will be amazed how long that is.
Batteries will always cheaper than replacing your drone due to a fire or malfunction.
Save for the newer drones and sell your old drone you will never regret it.

Flight time is always better than Hoover time. By the way DJI does there test indoors and quote the times until crash. We can’t afford that

Some of us have been modifying DJI batteries or the drones themselves to accept external batteries since 2015 to achieve 30+ minute flight times. No issues other than the expense and hassle of dealing with external batteries, that need to be charged separately. However, to your point, once realistic stock flight times exceeded 25 minutes on the P4P, it hasn't been worth the hassle. The Mavic 3 finally has broken the 30 minute stock flight time barrier with supporting range, and the Mini 3 Pro even exceeds that, with the new Plus battery.

 

[Anthony Ivory]

Some of us have been modifying DJI batteries or the drones themselves to accept external batteries since 2015 to achieve 30+ minute flight times. No issues other than the expense and hassle of dealing with external batteries, that need to be charged separately. However, to your point, once realistic stock flight times exceeded 25 minutes on the P4P, it hasn't been worth the hassle. The Mavic 3 finally has broken the 30 minute stock flight time barrier with supporting range, and the Mini 3 Pro even exceeds that, with the new Plus battery.

I have a mini 3 pro (with plus batteries ) and an M3 . I have been able to fly 30 mins comfortably with 15 to 20% remaining upon landing. If you are flying a true VLOS you may run out of things to shoot before you get a mandatory RTH.

 

[ClaudioNC]

Wow I guess I made my point : )
I’m really concerned that people want to take a risk with modified batteries that is a disaster waiting to happen.
If you haven’t flown a newer drone with about 30 minutes of flight time you will be amazed how long that is.
Batteries will always cheaper than replacing your drone due to a fire or malfunction.
Save for the newer drones and sell your old drone you will never regret it.

Flight time is always better than Hoover time. By the way DJI does there test indoors and quote the times until crash. We can’t afford that

The reasons for wanting to increase the operational flight time as much as possible go beyond the obviousness you wrote (...30 minutes of flight time you will be amazed how long that is).

There are situations in which it is more important to have the possibility of keeping the weighted drone in flight for few more minutes, accepting some risks that this necessarily entails.
From simple photographic shots in situations in which it is necessary to take advantage of sudden situations of good variable light (between and above the mountains, very high up and far away - as it is for me) not to be missed with more frequent forced returns of drone to home to replace the battery, to situations in which the possible loss of such an inexpensive drone is an absolutely insignificant detail, compared to a specific mission, as it can be in a war conflict.

And this is happening now, far away from you and from me, maybe also from everyone reading this chat.
You can guess where.

 

[ClaudioNC]

Modified Mavic 3, with two batteries connected in parallel.