Mavic Pro Battery Mod

[CyberNate]

Received the x4 7000mah lipo. Could not charge cell no1 above 3.75v , returned to Amazon for exchange. Pretty crappy for a €63 lipo.
Great Amazon service as always.

That sucks! Well have them send another. Just bad luck probably.

 

[CyberNate]

Received the x4 7000mah lipo. Could not charge cell no1 above 3.75v , returned to Amazon for exchange. Pretty crappy for a €63 lipo.
Great Amazon service as always.

By the way, interesting battery. It could be combined with a multistar 3000 for some serious capacity! Might need to lighten mavic slightly as it would be just a touch heavier than dual 4000 multistar, but you have way more capacity. I'm sure DirtyBum will overpack it as well. Heck, it may reach 8000mah on it's own with overpacking.

 

[MacIak]

By the way, interesting battery. It could be combined with a multistar 3000 for some serious capacity! Might need to lighten mavic slightly as it would be just a touch heavier than dual 4000 multistar, but you have way more capacity. I'm sure DirtyBum will overpack it as well. Heck, it may reach 8000mah on it's own with overpacking.

It is still a lipo but pretty light for its capacity. The idea was to test it against double 3000 MS and a MS 3000+4000 combo. Would be a good everyday long-range deal if it outperforms double 3000 MS. I cannot rest until i ve tried this one.

 

[CyberNate]

It is still a lipo but pretty light for its capacity. The idea was to test it against double 3000 MS and a MS 3000+4000 combo. Would be a good everyday long-range deal if it outperforms double 3000 MS. I cannot rest until i ve tried this one.

Hmmm, I found this video testing this 7000 x4 battery against a 5400 and it actually performed worse with flight time of 2 minutes less:

 

[lolo780]

While I'm waiting for my new TP4500s to arrive I've been doing some bodywork, and trying out some long range packs.

[emoji1]

 

[MacIak]

Info session:

Did a maiden flight with The Ugly today. Freshly hardwired, no issues before that.
I decided the first flight without external to test normal functioning. Parameters set for 53 kph max full stick in p mode. Wind was moderate. Flying oval pattern,1.5km legs. Crosswind on the straight legs out/inbound.
Issues started with the turn after outbound leg into the wind. With the 180 almost halfway got "compass error" and "exit gps". (Mind i had checked the sensors state during preflight, all greens and little deviation, all good.)
The Ugly started drifting heavily and i was not sure if i was controlling it. The nose pointed to homepoint with full throttle and still drifting with the wind. Made a 45 deg crosswind correction, still drifting the wrong way. The wind was not high enough to do this, almost seemed controls were not corresponding to stick input. Brought it back safely and after restart of motors it reacted normal until i did the same. Making the turn into tailwind gave no issues.
Decided to calibrate compass during this session and that solved it. I have no idea why the compass got messed up yet still indicated all good.
Next flight i loaded it with the double 3000. Flew it 32 mins in an inefficient pattern until 5%.
Like all modded birds with top-loading: got compass error when tilt became maximum into the wind. Pretty sure the external cables on the rear end or battery overhanging compass2 interfere. 3 different birds, same thing, with higher headwind, always no2 compass. This has zero effect on functioning since no1 is in charge but gives reduced redundancy.

More weirdness: Finally after landing the main battery was 3.55v, 3.35v, 3,55v.
Externals were: 3.48, 3.60, 3.50..
I find the no1 and no3 readouts acceptable.
The no2 cells being opposite puzzle me.
I need help understanding this, never happened before!

Still have to pull the data from the moverio when home.

 

[CyberNate]

Info session:

Did a maiden flight with The Ugly today. Freshly hardwired, no issues before that.
I decided the first flight without external to test normal functioning. Parameters set for 53 kph max full stick in p mode. Wind was moderate. Flying oval pattern,1.5km legs. Crosswind on the straight legs out/inbound.
Issues started with the turn after outbound leg into the wind. With the 180 almost halfway got "compass error" and "exit gps". (Mind i had checked the sensors state during preflight, all greens and little deviation, all good.)
The Ugly started drifting heavily and i was not sure if i was controlling it. The nose pointed to homepoint with full throttle and still drifting with the wind. Made a 45 deg crosswind correction, still drifting the wrong way. The wind was not high enough to do this, almost seemed controls were not corresponding to stick input. Brought it back safely and after restart of motors it reacted normal until i did the same. Making the turn into tailwind gave no issues.
Decided to calibrate compass during this session and that solved it. I have no idea why the compass got messed up yet still indicated all good.
Next flight i loaded it with the double 3000. Flew it 32 mins in an inefficient pattern until 5%.
Like all modded birds with top-loading: got compass error when tilt became maximum into the wind. Pretty sure the external cables on the rear end or battery overhanging compass2 interfere. 3 different birds, same thing, with higher headwind, always no2 compass. This has zero effect on functioning since no1 is in charge but gives reduced redundancy.

More weirdness: Finally after landing the main battery was 3.55v, 3.35v, 3,55v.
Externals were: 3.48, 3.60, 3.50..
I find the no1 and no3 readouts acceptable.
The no2 cells being opposite puzzle me.
I need help understanding this, never happened before!

Still have to pull the data from the moverio when home.

You see this issue on BOTH externals? This is likely a problem with the charger voltage meter. If it were 1 of the batteries, I'd say battery issue, but across both packs, must be charger meter. Use a multimeter to check the cells. The mavic battery mod has nothing to do with individual cell voltages as you are not using the balance lead. The XT60 connector is wired in series across the 3 cells and there's nothing the Mavic draw would do to unbalance those cells.

Edit: I should add, the charger may be bad. You may have charged the cells unevenly. So if you find that multimeter shows the same unbalanced result. Charge the packs and check with mutlimeter again across balance lead pins.

 

[MacIak]

You see this issue on BOTH externals? This is likely a problem with the charger voltage meter. If it were 1 of the batteries, I'd say battery issue, but across both packs, must be charger meter. Use a multimeter to check the cells. The mavic battery mod has nothing to do with individual cell voltages as you are not using the balance lead. The XT60 connector is wired in series across the 3 cells and there's nothing the Mavic draw would do to unbalance those cells.

Edit: I should add, the charger may be bad. You may have charged the cells unevenly. So if you find that multimeter shows the same unbalanced result. Charge the packs and check with mutlimeter again across balance lead pins.

The batteries were charged evenly and voltage confirmed by multimeter. Also after flight. The packs are plugged in parallel to the mavic, i use a single mod.
What threw me off also the main pack, middle cell way lower than the others opposite to the external where the middle cell was way higher..

 

[CyberNate]

The batteries were charged evenly and voltage confirmed by multimeter. Also after flight. The packs are plugged in parallel to the mavic, i use a single mod.
What threw me off also the main pack, middle cell way lower than the others opposite to the external where the middle cell was way higher..

Doesn't make any sense. The individual cells are not controlled nor monitored by Mavic if you are simply connecting the XT60 leads to to a direct battery mod. I've never seen that, except for when I have a bad cell in a battery, but I haven't see a mirror image across 2 packs like that.

 

[lolo780]

Thanks to @BudWalker for his hard work on Csview, here's a watt second plot of my battery setup. DJI battery plus Thunderpower 3500HV and 4500HV, 40.5 minute hover, 414,000 watt seconds to the motors.

What I'm interested to see is the same data from a 2 x Multistar 4000 setup, or any other long range setups.

 

[MacIak]

Received another 7000mAh x4 lipo. This also reacts like the previous one. Tried 2 different chargers. The first one charging at 4A after 4 hours still does not stop balancing even cells show 4.20, 4.20, 4.21. Other cheaper charger that only charges via balance plug (800mAh max) also keeps blinking forever. Took ik off the charger with cells indicated as above also later in the eve but could not fly. Wx is horrible here. Next morning one of the cells already at 4.19, 4.17, 4,21.
I never had this with any lipo except very abused ones but even those would stop balancing at some stage with deviations cause the charger (hyperion duo) could not figure it out anymore.
Still have to do a flight test but feeling pessimistic. My advice would be to stay away from these for now, i do not like the way these behave.

 

[lolo780]

As delivered, no connectors.

Light as they get.

XT30 with short 16ga leads

Finished with kapton tape back on. Thunderpower uses a 5 pin balance plug with a resistor for the unused lead. That had to go and now the pack has a cut down 4 pin. Will get some JST extension harnesses for charging.
229wh/kg and 20.09mAh/g!

 

[lolo780]

Stock battery as light as it gets. I just did two here and one is 7g heavier than the other. I wonder if that translates to 3.7% more capacity as well?

 

[angusc]

Stock battery as light as it gets. I just did two here and one is 7g heavier than the other. I wonder if that translates to 3.7% more capacity as well?

What are you planning to do with the stripped down stock batteries? What it's the weight off a stock battery fully cased?

 

[Blade slap]

What are you planning to do with the stripped down stock batteries? What it's the weight off a stock battery fully cased?

Me too I fly with a stripped dji battery the original one is 246-250 gr taking away 50 gr you can obtain 1-1.5 min more , I also take away other part from Mavic even if they are onlu 3-5 gr less I made because better to take away gr than add to have more time

 

[angusc]

Me too I fly with a stripped dji battery the original one is 246-250 gr taking away 50 gr you can obtain 1-1.5 min more , I also take away other part from Mavic even if they are onlu 3-5 gr less I made because better to take away gr than add to have more time

Please can you post some photos of your stripped down battery set up off and on the AC?

 

[Blade slap]

This is my mavic , I forgot to precise that 1-1.5 min more are also with new propeller.
After so many noise tests on mavic pro with old and new propeller, due bad weather and enough space available, I spent time testing in hovering to be able compare time without types of flight, wind or speed influence etc the results in annex. I remind everyone that flight time at optimum speed can also lead to 10-15% more than hovering time . In order to carry out the tests at the limit I clearly had to alter some of the default security parameters on the mavic.

 

[MacIak]

Just some findings below. Had some dry weather today. Windy and gusty so no good results but still able to compare a couple of batteries. Aim was to see how the very pricey Hubsan x4 pro 7000mAh lipo performs compared to a 5200mAh MS LiHv.
Parameters configured for max 54km/h in P-mode. Flights performed max stick input.
(Into the wind the max speed would become 38km/h to give an idea of headwind)
Landed in Lihv cases 8-10% juice, lipo with 4%.

Stock: landing 3.6v/cell, 18 mins.

5200mAh Lihv: 3.65 main, 3.68v ext. 27 mins

3000+4000mAh combo Lihv: 3.65 main, 3.68v max ext. 29 mins. Indeed they burn down equally!

And now.....the 7000 Lipo:
Main 3.50v, ext 3.80v. 21 mins.....!!!!!!!!
That is useless.
Basically the mav shutdown when i unplugged the external.
Also when started i could get no GPS lock with this battery although the mav was "seeing" 21 sats. Once landed/took off it locked but during flight it went exit-gps again for some minutes.
This battery does funny stuff and i absolutely do not recommend it.
It is mounted the same way as the rest, on top slightly overhanging the GPS unit.

Edit:
The temp was 4deg C.
Into the wind RPM regularly above 9k with externals hooked.
Does anyone know which RPM equals 100% on mavic?

 

[angusc]

Stock battery as light as it gets. I just did two here and one is 7g heavier than the other. I wonder if that translates to 3.7% more capacity as well?

Thanx for the information. One more question how much does the circuit board weigh on its own?

 

[lolo780]

What are you planning to do with the stripped down stock batteries? What it's the weight off a stock battery fully cased?

Fly them. The upper shell is 20g, lower 8.2g and 4g for the black peel off covering. Add back 2g for mounting and it's an easy 30g off. This stock Mavic with Platinum props started at 732g so 4.1% is a nice improvement.

I've never removed the circuit board but I recall someone did it and posted bare cell pack weights.