Potential Dual Battery Support

cybertech · Jan 24, 2017

AlanTheBeast said:
Yep, I've seen a video of that in flight with transmitter mod too:

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(Edit: Corrected the link)

Any wiring diagrams for the lipo addition?

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dsd317 · Jan 24, 2017

I'm not even going to reply to it's latest comment. I'm guessing it abuses it's power of authority because it thinks it's "god" (according to its name).

Sorry guys...I'm done with it and won't deviate from this thread's intent. We can proceed with discussion on Potential Dual Battery Support.

Jake Galloway · Jan 24, 2017

I wonder if it would as easy as 3D printing a mount that snaps into the factory battery location and has an extension on either side for 2 batteries to snap in. The wiring would be in parallel, and you wouldn't need to solder anything to the main board.

cybertech · Jan 24, 2017

BTW... I'm not involved in the fuss, but as a casual observer, let me ask if there is anyone in here that has NEVER EVER EVER, broken any of the FAA guidelines. Line of sight, fly at night, maybe flew to 401 feet. I want to meet that man.

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Chase R · Jan 24, 2017

Jake Galloway said:
I wonder if it would as easy as 3D printing a mount that snaps into the factory battery location and has an extension on either side for 2 batteries to snap in. The wiring would be in parallel, and you wouldn't need to solder anything to the main board.

Hmm. I was thinking vertical mount. I wonder if a side by side would be more stable. Any physics gurus in the house?

AlanTheBeast · Jan 24, 2017

AyeYo said:
Given that the battery sits on top of the craft, I see no reason they couldn't add a small hump to increase battery capacity 20-30%. Not sure if the flight controller would need a retune with the higher center of gravity though.

For a small bump up camel hump I doubt it would change much. The mass would still be below the rotor heads.

Reverend Greg · Jan 29, 2017

It's always a good idea not to change where the center of gravity in all three axes.

IADRN43 · Jan 29, 2017

AlanTheBeast said:
Packaging the batteries with the current smart battery enclosure (just more volume) would result in a more modest increase in weight, I believe.

Nobody says the flight time (or range) need to double - just that, heck, we want more!

I suspect the engineering constraint was as follows: "Design a compact, folding drone that carries this camera for 20 minutes or more up to 65 km/hr and can sell in the US for $999 with 40% gross margin."

I'd add "Oh - and humiliate GoPro in the process" but I'd bet the Mavic project launched long before the Karma was announced*.

And of course I have no idea what GM goal management imposes on engineering.

*Somewhere I stumbled on a statement that said the Karma was actually designed (manufactured) by DJI for GoPro... anything to that?

If they did design it, they couldn't have picked a better time to push the self destruct button on it.

AlanTheBeast · Jan 30, 2017

Reverend Greg said:
It's always a good idea not to change where the center of gravity in all three axes.

The change in CoG vertically would have so little impact for a "bulkier" battery as to be well within the existing control laws. The same laws that handle strong gusts of wind so well. I've seen one video with a GoPro added on top and the vehicle was very stable in flight. Only when he extended it many inches above did it get unstable.

Others are adding devices like radio locators off centre in x,y and probably z axis' to no ill effect. That's far worse that a change that results in a cm or 2 of vertical axis change alone.

John Shaw · Jan 30, 2017

AlanTheBeast said:
The change in CoG vertically would have so little impact for a "bulkier" battery as to be well within the existing control laws. The same laws that handle strong gusts of wind so well. I've seen one video with a GoPro added on top and the vehicle was very stable in flight. Only when he extended it many inches above did it get unstable.

Others are adding devices like radio locators off centre in x,y and probably z axis' to no ill effect. That's far worse that a change that results in a cm or 2 of vertical axis change alone.

I agree with your comments and it is good data. In addition we should realize as the CG rises it is taking more engine activity and as you point out it reaches a limit that the drone can't deal with. More engine activity uses more power and this results in a decrease of flight time and this needs to be taken into account. So I expect there is a benefit but we need to be realistic on the benefit.

AlanTheBeast · Jan 30, 2017

John Shaw said:
I agree with your comments and it is good data. In addition we should realize as the CG rises it is taking more engine activity and as you point out it reaches a limit that the drone can't deal with. More engine activity uses more power and this results in a decrease of flight time and this needs to be taken into account. So I expect there is a benefit but we need to be realistic on the benefit.

Good points.

Doing a crude "hanging CoG" I put it at just forward and above the forward acoustic element - about 1 cm below the bottom of the battery.

That point is well below the fore rotor plane, but only slightly below the aft rotor plane.

So it may indeed be more critical than I thought.

For amusement see: Not the first camera test ... the second. That's instability!

adamsweeting · Jan 30, 2017

DJI have engineered this thing within an inch of its life. Adding more weight will surely then make the quad less efficient(?)
I've been building these things for years, and weight/power/prop size is a fine balancing act

LakeTravis · Jan 30, 2017

cybertech said:
BTW... I'm not involved in the fuss, but as a casual observer, let me ask if there is anyone in here that has NEVER EVER EVER, broken any of the FAA guidelines. Line of sight, fly at night, maybe flew to 401 feet. I want to meet that man.

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Nice to meet you adamsweeting, I am not a part of this fuss either, but I never have. I have been a private pilot for almost 50 years and have never once knowingly, or purposefully violated FAA regulations. A person's life is far more important than the thrill of flying higher or farther. And that's more than my own humble opinion.

The following does NOT apply in the National Air Space.

AlanTheBeast · Jan 30, 2017

adamsweeting said:
DJI have engineered this thing within an inch of its life. Adding more weight will surely then make the quad less efficient(?)
I've been building these things for years, and weight/power/prop size is a fine balancing act

I guess you haven't seen the various mods people have been doing. (From "reasonable" to "pushing it" to "obviously stupid").

Also, a well designed control system is never "delicately balanced" but rather has a lot of margin to insure stability.

dcb942 · Jan 30, 2017

cybertech said:
BTW... I'm not involved in the fuss, but as a casual observer, let me ask if there is anyone in here that has NEVER EVER EVER, broken any of the FAA guidelines. Line of sight, fly at night, maybe flew to 401 feet. I want to meet that man.

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There are some guys who fly their phantom at a park near me. I only ever see them go up and down to about 100 feet. Whatever floats your boat I guess.

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Squamer · Jan 30, 2017

LakeTravis said:
Nice to meet you adamsweeting, I am not a part of this fuss either, but I never have. I have been a private pilot for almost 50 years and have never once knowingly, or purposefully violated FAA regulations. A person's life is far more important than the thrill of flying higher or farther. And that's more than my own humble opinion.

The following does NOT apply in the National Air Space.
View attachment 5397

Curious why did you buy a Mavic for 999$ then instead of a Hubsan or a Toys R Us special, something that can only fly within line of sight. What is line of sight out of curiosity anywyas, a couple hundred feet?

dewster · Jan 30, 2017

I saw a YouTube video of two extra lipos attached to the Mavic with long range antennas. I'll post it when I find it again.

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jackgarner · Jan 30, 2017

Squamer said:
Curious why did you buy a Mavic for 999$ then instead of a Hubsan or a Toys R Us special, something that can only fly within line of sight. What is line of sight out of curiosity anywyas, a couple hundred feet?

If you fly at night with some bright lights..? 9k feet..

cybertech · Feb 6, 2017

LakeTravis said:
Nice to meet you adamsweeting, I am not a part of this fuss either, but I never have. I have been a private pilot for almost 50 years and have never once knowingly, or purposefully violated FAA regulations. A person's life is far more important than the thrill of flying higher or farther. And that's more than my own humble opinion.

The following does NOT apply in the National Air Space.
View attachment 5397

Out of curiosity, how many airplane pilot errors have caused death and how many drone accidents have caused death? Is this even comparable... And out of extreme curiosity, has there been a drone related fatality? Even while it was an unregulated hobby?

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