Li-Ion or Li-Po for drones and airplanes? Which one is better?

Many people want to replace Li-Po batteries with Li-Ion batteries to go further. At first glance, the Li-Ion pack made from 18650 cells is just better: similar weight but twice the capacity. And can be safely discharged even below 3V per cell. The reality is often disappointing, and there is a price to pay.

[tedhancock]

Great video as always. I would just add that the surge in battery wholesalers in the past 2 years has really changed the economics. For example, you can get LG MH-1 or 18650BD cells with 3.2Ah and 10A continuous for about 1.50 USD each. Lately "salvage" means never used because companies go bankrupt before even selling one scooter or bike. So, a 4s2p is maybe 13 USD with wires and heat shrink and is good for maybe 4 times the charge cycles of LiPo. Another advantage of LiIo is configuration. You can pretty much make the pack any shape you want. Center of gravity off? Form a 4s tube that runs the length of the craft. Only have an "L" shaped space left in your bay? No problem. Lastly, with balance equalizer boards, you can say goodbye to balance chargers and hello to 24/7 cell balancing, including during flight, at any discharge level. In other words, LiIo looking better every day.

[dividingbyzerofpv]

Been flying 18650 VTC5D as my preferred cell and VTC6A for almost a year now. Primary pack is 6s2p configuration for 7in on 2806.5 1300kv Avengers or 10inch on 3115 640kv motors.

Can very nearly rip quite nicely on 3s VTC5D packs with 3600kv 1406-1506 sized motors and 3.5in triblades. Best to have an amp meter so you can use Betaflight to run up your motors tab and see at what throttle you hit 15 amps and 25 amps. Then make sure you have throttle % active in your OSD because many of the small budget 4:1 escs do not have a current sensor so go by throttle % instead.

Have also run two packs for 6s4p on 13inch Xclass cruising for 18 minutes at a constant 50mph. Soon will have 4 sets of 4s2p built for 6in drones but used for paralleling and series for 8s4p on the Xclass becase it really wants 32v instead of 24.

[p.]

You ever should keep in mind when using liion. Due to the voltage drop you should always add 1cell. So if you're using 4s, with liion you take 5s and you're fine.

For high current use vtc6 with 3000mah, for lower current use GA series with 3500mah.

[_grox_]

Answer is clear.
Li-Po-->Racing/Freestyle (Performance)
Li-Ion-->Long Range (Endurance)

[astromancer]

I'm using 4S3P battery (Molicel M50A cells) on my 2m Opterra. Gives me over an hour of cruise time with a comfortable reserve.
BTW thanks for the tip on the soldering acid!

[power-max]

Tesla's new cylindrical cells are pretty impressive, they modified the construction of the cell to avoid all the current going through small tabs, allowing the cell to dissipate heat more efficiently and reduce ESR. I expect these cells, with the right chemestry, to perform on-par with pouch cells (what everyone in this hobby calls "LiPo" (for the record, they both have polymer separators, but there are many dozens of lithium chemistries out there that are subsets of lithium ion. the high performance 18650's use INR.)

[SandyWise]

Thank you for contributing to the advancement of this hobby, as always, keep up the good work.

[paulblack]

These cells are great for many applications. The current limitation does make it tricky for hobby use though. Since the only real way to lower current for a given vehicle is to add cells either increasing voltage or running them in parrallel, either way you need more cells. For a flying machine that means more weight and space needed as well as cost. This quickly takes us past the point of diminishing returns. However, if you do run parrallel packs you really up your capacity. So a carefully planned craft could yield great results in terms of flight time. I just purchased some sony 30a rated cells to mess around with but they are NOT cheap for the real ones. It's going to be hard to beat lipo for the time being.

Cheers

[padcom]

Good video, Paweł! Thanks!

From experience using a 4S1P Sanyo GA (alternatively LG MJ1) on the Z84 during takeoff it does take more than the max 10A (as per spec). This, however lasts only for about 5-7 seconds because the moment the plane starts moving the strain on the propeller decreases rapidly as soon as the air starts moving through it. Using autolaunch is even better because the moment the prop starts the plane already is moving forward and thus the time the battery experiences high drain is even shorter.

I also use a 3Ah HG2s (20A) on my 250mm miniquad and I get around 15-18 minutes of cruising (no aerobatics!). The pack really weights a lot less than the 3Ah 2S lipo that would make the quad unflyable.

[danjensen]

Dude I really really like your videos. I started a Inav adventure with a 7” build about a month ago and watched many of your videos to build it . Maiden on Sunday went perfect . 9 minute flight time on 4s 1500 lipo 3.8 per cell after rest . 20 satellites. I was too paranoid to try RTH or position hold but everything else worked . Very stable and easier to fly acro then stable mode . Now of course it’s time to build some 18650 packs.

[copyandpastification]

would a 3s li ion for a 1400mm skysurfers (bixler type) with 6 inch prop be good enough taking into account that it has flaps and a speedebee mini with GPS?

[divya_]

Can you use a supercapacitor to help with the takeoff and cruise on li-ion to get the best of both worlds?

[BuildTimeMC]

Do you have to storage discharge li ion batterys like lipos?

[큐큐-fe]

Hi~
Let me ask you a question.
It's a 3 inch cine hoop.
In the video, there are videos of making a pack with 4 lithium-ion 18650 batteries and flying it with an FPV long range.
With excitement, I ordered batteries and made a pack.
LGDBHG21865 3000mA.
The problem is... When I hovered, the yaw tick symptom reappeared after it came up, and, after a few seconds, the low-voltage buzzer sounded and the aircraft sank.
If I open it again, it opens repeat...
So, I changed the low voltage warning in Beta Flight to 2.7V, and when I turned it on, there was no sound.
If I take a break for a while, it will float again. But it sinks again... The battery is hot, and the voltage is 3.8V... TT
I bought 40 tablets... but I can't use them all?
How do people use? Batteries were also made by buying anything.
Is my FC the problem? Or is there a special setting for Li-ion?
FC is IFlight SucceX Mini F4 V3 Stack, and the manual says 2~6 Lipol. Do I have to use only Lipol? Can I change FC?
Why is this happening?
It's a waste of money/work time.
I'm serious~~ Please advise.~~ TT

[pilotlawaran]

Is li ion hard to control throttle? Im learning hover with li ion battery is so difficult..

[carloszaera]

I'm testing the Samsung 21700 40t. In the Fms cessna the average consumption is 15A and peaks of 20, with very little power drop compared to lipo.
I have tested a 40 A discharge bench and they can withstand them but with more pronounced power drops and high temperatures. I think it is a good alternative in motorsailers.

[helicocrasher]

Well stated Pawel, for wing cruiser LiIon 18650 are cool. I can fly 45 minutes plus with the mini AR Wing cruising 60+kmh on 3s Sony VTC6. Launch no issue using iNav autolaunch,

[pratikppm]

Hi Pawel! For an airplane, what do you think, if we use a small Lipo and a li-ion pack in parallel? The lipo will compensate for the high current demand at the launch and the li ion will do it's job for the rest of the flight?

[klonikFPV]

I was wondering can I maybe have two packs on my drone paralel? One would be li-po to have big current when needed and second pack with li-ion to increase capacity. But I will need to invest probably in 7 inch drone before testing this approach. :-/

[pixelcomet]

My experience: 5" slim frame, full Gopro8, 2550KV 5S motors, 5.1x3.1 props, LiIon 6S pack 3150mAh: hovering/slow cruise (first test) flight time 25minutes. end voltage 2, 5V (sum 15V at the end)