I just received a MAXX UAV dual LiPo battery adapter (DJI Mavic Pro Battery Adapter) for my bird, and their dual LiPo saddle mount (DJI Mavic Battery Mount (Pro / Platinum)) for the same will arrive this morning. No, I don't have any connection with MAXX UAV, in fact I'm kinda PO'd with them because I paid shipping on two items rather than one!
I plan to do a hover test using a stock battery that is at least 1 year old, a fresh new stock battery, then each with a small variety of LiPo batteries in search of an optimal ratio of flying time versus bird weight.
The assumptions I make are that the stock Mavic battery is a 3S Lipo configuration that has three cells wired in series giving a DJIi rated voltage of 11.4 volts and an amperage of 3830 milliamps.. A single fully charged LiPo cell is about 4.2 volts, and is considered discharged safely at 3.0 volts. The battery power is brought out to the main body of the Mavic Pro connector on (from left side of the body) pins 2 and 3 for the negative power, and pins 5 and 6 for the positive. Power from the battery is ONLY hot when the battery is turned on with the button sequence used for powering up the bird.
The MAXX UAV adapter cleverly connects between the body connector and the battery without soldering or other warranty-voiding actions, and brings those connections up into a plastic housing that has two XT60 female connectors for use with 3S Lipos. The optional battery saddle is just one way of mounting additional batteries, some folks use Velcro or other means of mounting.
So when adding LiPo batteries of the same 3S voltage you are INCREASING the available amperage (milliamps) which is POSSIBLY what is going to give you a longer flying time. Adding two 1800 ma batteries might theoretically give you close to double the power, but you have to consider the added weight of the batteries as a factor that will require more amperage for the bird to accommodate. And 3S LiPos are available with XT60 connectors from under 1000 ma on up to over 5000 ma. So is there a sweet spot between added weight and optimal flying time? Let's take factors such as stress on the props and air resistance out of the discussion.
I fly almost exclusively with Master Airscrew props, with Mavic Pro Platinum props as backup. You can tie the bird to a lead brick and give it full takeoff power and sincerely doubt you're going to have a prop break. And the air resistance I suspect would be a small factor given the frontal area of the bird already. I suppose you could design little nose cones for the batteries for better aerodynamics and print them with a 3 D printer. I doubt you'd yield any noticeable improvement!
So I plan do do some testing and report back on my results. Others may wish to do the same, perhaps taking another approach. My hope is that we'll get some real world numbers and experiences rather than a lot of wordy argument,
I plan to set up a benchmark flight using the Litchi ap with a low-level hover to test batteries and different configurations. My methodology is to weigh the stock bird with a fresh battery that's been put through DJI Assistant validation, then do the hover test to 30% battery with a stopwatch. I'll repeat with some of my year-old batteries, and with various 3S XT60 LiPos to find an optimum setup that gives the longest time for the given loaded weight, charting and recording each test.
I don't anticipate anything more than a configuration that would prove worthy of a longer field test that gives me a level of confidence for prolonged flying. I welcome any comments, suggestions, or criticism as long as they're not unreasonably speculative. Real-world feedback, People!
I plan to do a hover test using a stock battery that is at least 1 year old, a fresh new stock battery, then each with a small variety of LiPo batteries in search of an optimal ratio of flying time versus bird weight.
The assumptions I make are that the stock Mavic battery is a 3S Lipo configuration that has three cells wired in series giving a DJIi rated voltage of 11.4 volts and an amperage of 3830 milliamps.. A single fully charged LiPo cell is about 4.2 volts, and is considered discharged safely at 3.0 volts. The battery power is brought out to the main body of the Mavic Pro connector on (from left side of the body) pins 2 and 3 for the negative power, and pins 5 and 6 for the positive. Power from the battery is ONLY hot when the battery is turned on with the button sequence used for powering up the bird.
The MAXX UAV adapter cleverly connects between the body connector and the battery without soldering or other warranty-voiding actions, and brings those connections up into a plastic housing that has two XT60 female connectors for use with 3S Lipos. The optional battery saddle is just one way of mounting additional batteries, some folks use Velcro or other means of mounting.
So when adding LiPo batteries of the same 3S voltage you are INCREASING the available amperage (milliamps) which is POSSIBLY what is going to give you a longer flying time. Adding two 1800 ma batteries might theoretically give you close to double the power, but you have to consider the added weight of the batteries as a factor that will require more amperage for the bird to accommodate. And 3S LiPos are available with XT60 connectors from under 1000 ma on up to over 5000 ma. So is there a sweet spot between added weight and optimal flying time? Let's take factors such as stress on the props and air resistance out of the discussion.
I fly almost exclusively with Master Airscrew props, with Mavic Pro Platinum props as backup. You can tie the bird to a lead brick and give it full takeoff power and sincerely doubt you're going to have a prop break. And the air resistance I suspect would be a small factor given the frontal area of the bird already. I suppose you could design little nose cones for the batteries for better aerodynamics and print them with a 3 D printer. I doubt you'd yield any noticeable improvement!
So I plan do do some testing and report back on my results. Others may wish to do the same, perhaps taking another approach. My hope is that we'll get some real world numbers and experiences rather than a lot of wordy argument,
I plan to set up a benchmark flight using the Litchi ap with a low-level hover to test batteries and different configurations. My methodology is to weigh the stock bird with a fresh battery that's been put through DJI Assistant validation, then do the hover test to 30% battery with a stopwatch. I'll repeat with some of my year-old batteries, and with various 3S XT60 LiPos to find an optimum setup that gives the longest time for the given loaded weight, charting and recording each test.
I don't anticipate anything more than a configuration that would prove worthy of a longer field test that gives me a level of confidence for prolonged flying. I welcome any comments, suggestions, or criticism as long as they're not unreasonably speculative. Real-world feedback, People!
