DRONE Autonomous Battery.pdf (125.3 KB)
Hi Core- Electronics
Les Kadlof and I have been in contact with guys numerous times in regards to our drone project. You have been very helpful.
Just wondering if you can give any tips on the following attached diagram?
Obviously we want the drone to be a safe project and have all the right components.
Your knowledge will be much apricated.
Cheers Rob Diconi
Hi Robert,
18650 LiPo batteries are fairly universal for being low cost and high capacity, but do not have great continuous current delivery relative to their size and mass.
The 18650s we have are listed with a standard discharge rate of 0.2C and a max discharge of 1C giving you 520mA standard and 2600mA max per battery.
I would assume they would need to be charged at a rate less than or equal to their standard discharge rate, so at least 5 hours per charge.
From the little bit I know about drone racing there are some LiPo pouch style batteries that are rated for discharges around 40C, and that are safely charged at 1C.
For example:
Can deliver 12.5 Amps continuously, and could charge in one hour weighing in at 40 grams with connectors.
Hi Trent
Our drone will be inside moving no faster than walking pace, not racing. Does this change the equation at all?
Thanks Robbie
Hi Robbie,
The battery will be determined last as it depends on the motors, ESCs and receiver chosen.
Do you know what voltage and current supply your drone will need to power it’s motors?
What do you think?
Cheers robbie
As you are aware the drone isnt built for speed and agility, its more to do with the cameras and sensors sending data to our programs. Landing back on the hub and charging is a reasonable amount of time.
Ah that’s perfect!
Just confirming this 4-in-1 ESC will drive 4 brushless motors and the rated current is to drive all 4?
If that 30A continuous current on the ESC spec is 30A x4 to supply all 4 channels you should be fine. If that is 30A total and each motor has a peak current load of 23A you may have a problem.
A 5V BEC should deliver enough voltage for a Pi Zero but you will need to double check the current the BEC is rated to deliver. The Raspberry Pi site lists the Pi Zero as needing a 1.2A supply.
Something like this can deliver 105Amps continuously and peaks up to 210 Amps. That should cover your four brushless motors peak draw of 92 Amps.
is there anyway of using 18650 batteries, they are safer and lighter and can discharger a lot less
Hi Robert,
18650s, while safer, will never be lighter than a LiPo due to the added weight of the metal casing. They also generally aren’t structured internally to provide the current capacity you’re looking for without a ton of cells. I’m sure Trent is going to come back with some maths to back this up, but I recommend LiPos for this specific application.
-James
yes the above is correct
Maybe, I’ve done a bit of napkin math here. If we still want a 4S (14.8V nominal) battery that can supply 92 Amps peak, then we can see how many 18650s we need in series and parallel.
These ones have a C rating of 2.6 and a peak discharge of 1C.
So to supply our 92 Amp requirement we would need 92 / 2.6 = ~36 batteries because we round up.
To get our 4S voltage we will need 36 x 4 = 144 batteries.
I’m not sure on the weight of 18650s but I assume this is too heavy.
To clarify 18650 is a form-factor of LiPo battery, whereas what I have linked is a LiPo pouch form-factor.
James is correct though that one is optimised to be lightweight and have as much current delivery as possible, whereas the other is designed to be more robust and long lasting.
can this lipo still be charged wireless with the 12v/3a charging mod?
Do you have a link to the specs of that battery?
That’s still only one tenth of the maximum current your motors can draw.
Perhaps your motors are oversized?
I dont think the 1507- 3800kv are using 10A
the guys from phaser said “i could use 3 minimum 18650 batteries for the 1507 motors”
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