80% more run time than lipo

digdat0 · Jul 16, 2017

I posted on the guys Google pics, invited him (him?) to come visit us at the battery mod thread. he responded and posted his code to github and more detail. Hes using the board to do what ScottJD indicated .. based on volts, sending different readings to the aircraft so it keeps flying longer. Very simple and pretty smart. below is the github

mavic_bat/mavic_bat.ino at master · sincoder/mavic_bat · GitHub

ZeeKodadii · Jul 16, 2017

ScottJD said:
TGG???

Lol wow I didn't even realized I posted this it's nothing probably a butt post

Hauptmann · Jul 16, 2017

LOL. You really got us going.

ScottJD · Jul 16, 2017

ZeeKodadii said:
Lol wow I didn't even realized I posted this it's nothing probably a butt post

Had me going, off the top of my head I had:
The Good Guys
The Great Gatsby
The Gang Green (New York Jets website)

The google said some weird stuff also, so I gave up and asked,
Scott

ScottJD · Jul 16, 2017

digdat0 said:
I posted on the guys Google pics, invited him (him?) to come visit us at the battery mod thread. he responded and posted his code to github and more detail. Hes using the board to do what ScottJD indicated .. based on volts, sending different readings to the aircraft so it keeps flying longer. Very simple and pretty smart. below is the github

mavic_bat/mavic_bat.ino at master · sincoder/mavic_bat · GitHub

What picture were you diverting with him on?

Ok, now I see his comments that I've signed into google with my google plus account. But I was signed in with the YouTube channel account before.

He has a video also showing the mavic flying off 3 18650 cells. He also mentioned on the DJI mavic batter board image that if you use that board the voltage will be all wrong like I figured. It will probably fail safe and RTH way to early.
I'm couriouse to see what 18650 cells he is using?

https://photos.google.com/share/AF1...?key=SkVoSXZhUXBCcW5Scl9pMVBJc1daQkV5OV9CcXBR

digdat0 · Jul 17, 2017

ScottJD said:
What picture were you diverting with him on?

Ok, now I see his comments that I've signed into google with my google plus account. But I was signed in with the YouTube channel account before.

He has a video also showing the mavic flying off 3 18650 cells. He also mentioned on the DJI mavic batter board image that if you use that board the voltage will be all wrong like I figured. It will probably fail safe and RTH way to early.
I'm couriouse to see what 18650 cells he is using?

https://photos.google.com/share/AF1...?key=SkVoSXZhUXBCcW5Scl9pMVBJc1daQkV5OV9CcXBR

Mavic - Battery life improvement & Internal Electronics

He is using 3S1P Sony US18650VTC6 3000mAh (Specs here

ScottJD · Jul 17, 2017

Oh no, you brought this up in another thread also now. Am I going to have to post everything twice now, lol. I see you've been talking with him.

Well I was sort of serious about trying this myself. I have two planes given to me, I haven't flown them yet, still need to fix some little things.
I have a electric spot welder and nickel strip for making 18650 battery packs. The spot welder is a cheap one originally made to run on a 240V grid with 40 amps behind it. But it will work ok at half with 20A at 120V. I've checked all the componenants, triac, capacitors, mosfets, and everything and all the internal parts are designed to run off of 120V or 240V.
I ran into a problem when I needed a separate breaker in my panel for 20A of power. Still wasn't getting 50%, but I did get some good welds. Then I realized the outlet is rated for 15A, the cord they put on the spot welder is rated for 13A at best, but it's a cheap power cord so I would give it a 10A carry rating, if that.
So I bought a 20A outlet, plug and wire last week and I'm going to retire the unit and my plug so this way it will get the 20 amps it needs. Once this is done I should have good welds all the time and can start building nice 18650 packs with thick pure nickel for a good current contact. Not the cheap nickel plated steal, but pure thick nickel. These will be quality packs, no damage to the batteries from a soldering iron or degraded quality of the cell from the heat of the soldering iron. I don't think people know how dangerous it is to solder 18650 cells.

I'm assembling a pack for USB power that can charge up to QC 3.0 over USB, or max of 2.6A per each USB port. I can also charge the lack in a coil,e hours with a 19V 60W laptop power supply. It's a neat USB battery, I've chosen to use Panasonic 18650GA cells for a balance between power and capacity.

The one plane runs off a single cell JST batter at 800mAh, and I think once I get ok flying it I will make a 18650 pack for it and do some time charting.

Maybe I'll finish my electric updates next week and can test again, make a few packs for the RC stuff and see how they fly? I'll see if I have time for it, or if I have a quality ESC I can change the cutoff voltage to 2.8V instead of the default voltage to get the most out of the packs.
Scott

BigMotor · Jul 17, 2017

Howdeedoodee said:
1 of these
EvoLite Kit Plus (Mavic Pro Edition)

1 of these
Mavic Battery Mod

1 of these 50 minute run time on mavic
7.0Ah 11.1v 120W Endurance
2 of the above batteries 1.5 hrs run time.

This has got to be tested, I'm waiting for my max uav antenna booster as above and will try.

I'm patiently waiting on someone to come up with a sound mod for the Mavic pro distance as well as battery flight time.
really interested in the the max uav antenna booster. just waiting on more input.....

Rodman · Jul 17, 2017

Very interesting read for a non engineering type as myself. I would purchase something to extend the flight time for my Mavic.

Howdeedoodee · Jul 18, 2017

ScottJD said:
Oh no, you brought this up in another thread also now. Am I going to have to post everything twice now, lol. I see you've been talking with him.

Well I was sort of serious about trying this myself. I have two planes given to me, I haven't flown them yet, still need to fix some little things.
I have a electric spot welder and nickel strip for making 18650 battery packs. The spot welder is a cheap one originally made to run on a 240V grid with 40 amps behind it. But it will work ok at half with 20A at 120V. I've checked all the componenants, triac, capacitors, mosfets, and everything and all the internal parts are designed to run off of 120V or 240V.
I ran into a problem when I needed a separate breaker in my panel for 20A of power. Still wasn't getting 50%, but I did get some good welds. Then I realized the outlet is rated for 15A, the cord they put on the spot welder is rated for 13A at best, but it's a cheap power cord so I would give it a 10A carry rating, if that.
So I bought a 20A outlet, plug and wire last week and I'm going to retire the unit and my plug so this way it will get the 20 amps it needs. Once this is done I should have good welds all the time and can start building nice 18650 packs with thick pure nickel for a good current contact. Not the cheap nickel plated steal, but pure thick nickel. These will be quality packs, no damage to the batteries from a soldering iron or degraded quality of the cell from the heat of the soldering iron. I don't think people know how dangerous it is to solder 18650 cells.

I'm assembling a pack for USB power that can charge up to QC 3.0 over USB, or max of 2.6A per each USB port. I can also charge the lack in a coil,e hours with a 19V 60W laptop power supply. It's a neat USB battery, I've chosen to use Panasonic 18650GA cells for a balance between power and capacity.

The one plane runs off a single cell JST batter at 800mAh, and I think once I get ok flying it I will make a 18650 pack for it and do some time charting.

Maybe I'll finish my electric updates next week and can test again, make a few packs for the RC stuff and see how they fly? I'll see if I have time for it, or if I have a quality ESC I can change the cutoff voltage to 2.8V instead of the default voltage to get the most out of the packs.
Scott

.
.
NewJust out of interest There's a video here of someone flying with just 2.7-2.8 volt left per cell at 2% battery left on the DJI GO 4 app

Isn't this close to the Titan cells? So would there be a need to do the magic reporting back to the mavic.
Maybe I'm missing something but this guy flew right down to 1% battery left??? So the mavic allowed the battery to run down to 2.7-2.8 volts at 1% left, I thought it would shut off before this??
Another thought!....Has anyone tried strapping a second DJI standard battery on the Mavic and done a cable mod so you have 2 x 3830mah = 7630mah,....then you would'nt have the battery reporting voltage problem.
Or even 3 mavic batteries 11490mah.
If you made up a cable to link original batteries up you wouldn't need to butcher or modify the batteries.
They only weight just over 200 grams so not that heavy.

dirtybum · Jul 18, 2017

just out of interest, Howdee, why did you post &quote yourself five times?

CyberNate · Jul 18, 2017

I also would love to extend flight time with 18650 cells, but we need the circuit board which feeds the battery details to the Mavic. You cannot run these 18650 cells in parallel to the Mavic main battery. You would need to replace the Mavic battery completely because the cell voltage range is not compatible. The Mavic will fly at lower voltages, but you won't have any details on remaining battery without some battery data fee to the Mavic. It's a piece of cake to run any battery by simply connecting directly to the main power leads, but getting battery details is the hard part. I've flown my Mavic on external batteries only (unintentionally) and it will fly WAY down to a low voltage. I flew mine down to under 2V/cell when it fell out of the sky. I could dig up the flight data for you guys. I lost my Mavic that flight because my Main battery switched off and without realizing it. The craft started spinning around and falling, but my video feed kept going all the way down. I was amazed later when seeing the voltage at 2V/cell in the logs.

Another interesting point. With external batteries connected WITHOUT the main battery, it will fly. You won't see any battery percentage details, but in the flight log, the voltage is reported as was in my case I described. Perhaps one could simply have a terminal window open and do a tail on the flight data log. There you would be able to see the per cell voltage. Someone could make an android app that shows the per cell voltage on the task bar.

Edit: Ok, I've uploaded the flight log. Go to
DJI Flight Log Viewer - PhantomHelp.com

Here you can see the details. You can re-upload in case the link times out. You can see at the end the voltage is at 1.769V/cell, 5.3V total for the battery and I have footage that I was receiving at that low voltage.

Autolanding kicked in at 3.283V, but was able to fly forward in a forced descent.

ScottJD · Jul 18, 2017

Howdeedoodee said:
Just out of interest There's a video here of someone flying with just 2.7-2.8 volt left per cell at 2% battery left on the DJI GO 4 app
Isn't this close to the Titan cells? So would there be a need to do the magic reporting back to the mavic.
Maybe I'm missing something but this guy flew right down to 1% battery left??? So the mavic allowed the battery to run down to 2.7-2.8 volts at 1% left, I thought it would shut off before this??
Another thought!....Has anyone tried strapping a second DJI standard battery on the Mavic and done a cable mod so you have 2 x 3830mah = 7630mah,....then you would'nt have the battery reporting voltage problem.
Or even 3 mavic batteries 11490mah.
If you made up a cable to link original batteries up you would need to butcher or modify the batteries.
They only weight just over 200 grams so not that heavy.

Howdee, you had a lot of interested in this, five times worth.
The difference is the characteristics of different batteries and how the voltage drops when they are under load.
LiPo cells maintain close to the real voltage even under load putting out ???? Let's say 15 Amps for a number, and the voltage was 3.0V. During the load of the Li-po pack it status close to the 3.0V per cell.

Li-Ion cells can also put out that 15 amps , but may drop on the voltage during this load instead of maintaining the 3.0V, they might drop to 2.7V per cell. This would trigger the voltage cut off. These are random numbers as an example, not based off any testing or measurements done from the mavic.
Just trying to explain the difference.
I hope this answer all five of your interests

Scott

Hauptmann · Jul 18, 2017

I hope you techies have this figured out by the time my batteries die. I'll definitely be on the market for longer life batteries

Howdeedoodee · Jul 18, 2017

dirtybum said:
just out of interest, Howdee, why did you post &quote yourself five times?

Sorry chaps! my computer screwed up and it looked like it didn't post/show up,
I tried it again and again and it still didn't show up,...however I've deleted duplicates

Howdeedoodee · Jul 18, 2017

ScottJD said:
Howdee, you had a lot of interested in this, five times worth.
The difference is the characteristics of different batteries and how the voltage drops when they are under load.
LiPo cells maintain close to the real voltage even under load putting out ???? Let's say 15 Amps for a number, and the voltage was 3.0V. During the load of the Li-po pack it status close to the 3.0V per cell.

Li-Ion cells can also put out that 15 amps , but may drop on the voltage during this load instead of maintaining the 3.0V, they might drop to 2.7V per cell. This would trigger the voltage cut off. These are random numbers as an example, not based off any testing or measurements done from the mavic.
Just trying to explain the difference.
I hope this answer all five of your interests

Scott

.
.
Just clutching at straws so to speak (don't know if you've heard that saying in the USA or its just a UK saying) but what about voltage regulators? surely there are step up voltage regulators the maintain a set voltage....right??....14.8 volt 4s Titan pack to step up voltage regulator to 12volt maintaining around 3.5 volts++

Here: Pololu 3.3V Step-Up/Step-Down Voltage Regulator S7V8F3

This step-up/step-down voltage regulator S7V8F3 is a switching regulator (also called a switched-mode power supply (SMPS) or DC-to-DC converter) that uses a buck-boost topology. It takes an input voltage from 2.7 V to 11.8 V and increases or decreases the voltage to a fixed 3.3 V output with a typical efficiency of over 90%. The input voltage can be higher than, lower than, or equal to the set output voltage, and the voltage is regulated to achieve a steady 3.3 V.
This flexibility in input voltage is especially well-suited for battery-powered applications in which the battery voltage begins above the desired output voltage and drops below the target as the battery discharges. Without the typical restriction on the battery voltage staying above the required voltage throughout its life, new battery packs and form factors can be considered

Apparently this comes in many versions voltages etc
http://www.robotshop.com/media/files/pdf/datasheet-2118.pdf

or if this board is not exactly right surely there something out there in the market which maintains 3.5 ish volts?

LM2587 DC-DC Booster Converter Step Up Voltage Regulator 3.5-30V ~ 4.0-30V
??NEW Voltage Booster Power DC Converter Step Up Regulator 12V to 13.8V 20A 276W | eBay