Hey all,

I recently built my own Li-Ion battery pack and in this weeks video I test it head-to-head against a Li-Po pack. Check out the video:


Looking forward to your comments here and on YT.

A hover test is not a good way to compare these two types of batteries. Nobody flies like that in the real world.

Thanks for sharing

Discharge rate is not the main issue comparing LiOn and LiPo. The LiPo has a greater power storage than LiOn per Kg. To do this comparison you need to compare batteries of the same weight.

mc54 Posted at 8-2 07:37
A hover test is not a good way to compare these two types of batteries. Nobody flies like that in the real world.

hey mc, while i agree that the battery needs to be able to provide more power than just a hover, to do a half way fair comparison in flight-time I thought the hover test was fine.

Further testing required, but signs look positive for the li-ion battery.

A J Posted at 8-3 00:31
Thanks for sharing

hey AJ thanks for watching

QuadcopterGuide Posted at 8-3 03:19
hey AJ thanks for watching

You're welcome

bjr981s Posted at 8-3 00:36
Discharge rate is not the main issue comparing LiOn and LiPo. The LiPo has a greater power storage than LiOn per Kg. To do this comparison you need to compare batteries of the same weight.

hey bjr,

i actually found the opposite is true. In my specific case here are the numbers:

LiPo pack 180grams per 1000mAh
LiIon pack 104grams per 1000mAh

this is why many fpv flyers that want longer flight times build li-ion packs.

Hello there Felix. Thank you for reaching out and for posting this video on how your build your own Li-Ion battery pack for your DJI FPV. Again thank you for your valued support and fly safe always.

QuadcopterGuide Posted at 8-3 03:53
hey bjr,

i actually found the opposite is true. In my specific case here are the numbers:

You are comparing Mandarins with Bananas.

As I said the difference is the Storage Power in the comparison. Not a MAh rating without a C rating.

The Measurement is in Watt hours not MilliAmp Hours.

Power in hours. Not current in hours.

And your hover flight is completely not relevant. You need to stress the amp delivery.

You will find your 1,000 mah hour battery will supply way less than 1,000 mah once you up the current demand.

I have recently tested the HobbyKing 3.0 20C 2S (2S2P) nanotech rx battery and advised HobbyKing of their mislabeling. I was going to use these in my Twin Scale SU35S turbine so tested their specific capability before I put them in my $30K jet.

It's actually a 2C battery. At 10C half its C rating it delivers 300mah before the battery brownouts and collapses. 1/10th of its stated capacity.

You need an actual battery discharger analyser to do your tests. The way you test is anecdotal at best.

Cheers

p.s. Forgot to add. LiOn batteries are a lower Voltage than LiPo batteries. So what Voltage is your 2 theoretical batteries you quoted?
Im not trying to be antogonistic, really. Its just you have the bull gripped firmly by the foot.

If you want to do a proper comparison you actually need to use the correct factors in play.  
  

bjr981s Posted at 8-6 07:09
You are comparing Mandarins with Bananas.

As I said the difference is the Storage Power in the comparison. Not a MAh rating without a C rating.

sure, Watt hours. Not 100% sure how the lower working voltage of li-ion does there. Of course flying with Li-Ion is going to be different than LiPo. I plan to fly differently with both.

I just got an over 14min flight in super gusty conditions flying at 45-55km/h. Not shabby.

DJI Stephen Posted at 8-3 20:09
Hello there Felix. Thank you for reaching out and for posting this video on how your build your own Li-Ion battery pack for your DJI FPV. Again thank you for your valued support and fly safe always.

No worries thanks for checking it out Stephen.

QuadcopterGuide Posted at 8-8 10:14
sure, Watt hours. Not 100% sure how the lower working voltage of li-ion does there. Of course flying with Li-Ion is going to be different than LiPo. I plan to fly differently with both.

I just got an over 14min flight in super gusty conditions flying at 45-55km/h. Not shabby.

The motors have a KV. That is the number of revs per volt. A lower voltage means that you have to apply more relative throttle to get the same revs. And the same lift from the props.

The esc and props consume power. P =VI

If the Power is the same to power the drive train then as V is Lower I must be higher so your comparison mAH hours is wrong.

You need more mah in a LiOn battery to do the same work as a LiPo.

I like that you are doing this comparison it should be done.

The mini uses LiOn batteries and a lot of people get confused as they have completely different characteristics to LiPos.

Good luck with your comparisons If you need someone to double check your assumptions I am happy the help.

p.s. LiOn batteries are way more easy to maintain than LiPOs and the LiHVs that DJI use.

Cheers Brian

QuadcopterGuide Posted at 8-8 10:14
No worries thanks for checking it out Stephen.

Hi there Felix. You are very much welcome and thank you for the reply. Have a safe and a happy flying always.

bjr981s Posted at 8-10 03:09
The motors have a KV. That is the number of revs per volt. A lower voltage means that you have to apply more relative throttle to get the same revs. And the same lift from the props.

The esc and props consume power. P =VI

Hey Brian,

thanks for your thoughtful comment. I'll reach out if the need arises.

It would be cool to be able to fly waypoint missions one after another on a calm day and just do lapse at a specific speed, then see how much longer the li-ion flies compared to the lipo.

QuadcopterGuide Posted at 8-13 11:18
Hey Brian,

thanks for your thoughtful comment. I'll reach out if the need arises.

Happy to help if need be.

If you use Ohms law you can judge the relative power of different chemistries. Its not 100% accurate as you need to use the nominal voltage as the capacity of the battery changes depending on its state of charge.

Used P=IV Where V is the Nominal voltage and I is a fixed calibration current.

I have been doing lot of battery testing recently and once I have the examples set up correctly I will put a battery lesson on my YouTube channel.

Very keen to see your results.

My tests have been about testing the C rating and the MaH storage capacity.

The fundamental results are quite interesting and proves that a battery cannot hold its C rated current throughout its storage range spec
.

This mind you is done with LiPos only. I only have 2 battery analysers of 230 Watts each at the moment 2 more on the way of 250W each. They can be wired in parallel to provide a 960 Watt load. They continually measure the voltage and power dissipated. So you can tell if it adds up to the specific mah spec. I have only been testing 2S and 3S batteries at the moment as I don't have the dissipation load to absorb more than 960 Watts. The analysers are set to a constant current load. They will not meet that load if it's above the 960W or until the voltage start to drop. I test them from Fully Charged to 3.3V. I don't want to overly damage them. This tests that their Mah rating can be provided at a max current of ??? measured value.I do it again at down to 3.7V per cell the nominal voltage that you should not exceed. At that provide a real time example of what you can expect in a flying model.

So I will be able to load a:
2S to P=IR I=P/V so 960/8.4 = 114A at full charge.
3S to 76A
4S to 57A
6S to 38A

Anything above that I can put in my pair of 105mm JP Ducted Fan, in my thrust measurement test stands with a pair of HobbyWing 200A ESCs. So should be able to stress test my larger 120C 6S batteries.

So good luck with your project It will help increase knowledge     

It still amazes me how confused people are about batteries. Particularly the drone community with DJI drones the owners the worst. They have been coddled by DJI for too long.   

Cheers Brian

Interesting watch (although too much DJI eeh DIY for me)