Getting to 100km, with a big help from GEB 8043125.

Today we decided to finally get out of the office and go fly !
I wanted to test a new pack which has been sitting on my desk for a while, a 14.8V 4s4p 24400mAh. 

This is a different type of lipo , with a energy density of 262 Wh/kg. 

Simply, this battery has an energy density which is x 1.62 of regular lipo (160 Wh/kg), which can help you get long flight time.  This GEB even beats the  VERY expensive Maxamps battery, which is 180 Wh/kg.  Ok, so the Maxamps can handle a few more C's. But if you are going for long flight time, then the GEB is for you !

The downside of this different battery chemistry is that the discharge rate is only 1C/2C maximum. You must take this into account when planning to use this battery. For example: a 3s1p 6100 battery should not be discharged at higher than 12.2A. A 4s4p 24400mAh battery should not be discharged at higher than 48.8A. A three second burst at 3C is supposed to be OK. If you discharge any lipo above its maximum discharge rate, it will instantly become damage and will never deliver the same performance as new.

So, with that in mind.. 

I grabbed a 680Pro by Tarot which I had laying around and threw on a Pixhawk on it. A quick auto tune and I was flying, albeit not very well- sorry Pixhawk you need more tuning. 

 

Since I only have 6S capable  speed controllers ,there was no possibility to go up to 8S. That will be by next test flight. 

 

The current needed to hover was about 30A, this is safe the battery pack I was using.

Pack was hot after the flight , but under 60 * C for sure. 

 

My plan is now to do a couple of more flights like this. I need to know if the battery will keep its capacity (performance) over multiple discharge cycles at 1.25C (30A).  I am concerned about the voltage sag which was at about 15% of capacity.  Battery getting hot is never good, either. 

Btw, loiter worked at the office, but drifted at the beach. I didn't debug it, but I guess I should just look at the logs. Flew in STABILIZE.

 

This flying day got me fired up to build a wing for the elusive 100km badge.. Actually, I think a 100 km flight with be piece of cake with a fixed wing.

If I can make  RVJET cruise at 50W @ 60km/h.... well, lets just say I might be going fishing to Bimini (200 km trip)

I will start with 14x5.5 CF multi rotor  prop and 380 kV , 22.2V .  We will need more pitch, but 5.5 is all I have atm. 

3s2p 6100 22.2V shown.  I will put more batteries , no worries. :)

SunnySky 3508 - 380kV

 

Here comes the plug, you can buy these batteries at RangeVideo. I know a lot of UAV guys have been looking for them.
If you need something with higher discharge rate (30C), I suggest to check the new 16Ah cells from Gens Ace.
they are 180Wh/kg plus the batteries themselves are very nicely assembled; aluminum radiator sheet over top and bottom, plenty of foam on the ends to protect the cells, overall I was impressed. You can use  single 6s 16000mAh pack on an S800. Probably 13-14 minute flight times with and NEX5 Zenmuse.
1. RV Power = Gens Ace cells
2. RV Endurance = GEB cells

 

Lastly, the video from this morning.

https://www.youtube.com/watch?v=BDP6EHtCAuQ

Views: 13068

Comment by renaud barbier on March 23, 2014 at 9:34pm

nice, what is the link to the battery you used?

Comment by vova reznik on March 23, 2014 at 9:55pm

Moderator
Comment by Gary Mortimer on March 23, 2014 at 10:28pm

Nice Vova, I look forward to adding your badge. Don't forget the KML ;-) My money is on you claiming further than 100km.

Comment by Thomas Robinson on March 24, 2014 at 12:37am

Is there somewhere I can get the weight of this battery? 

http://www.rangevideo.com/en/4s/311-rv-power-4500mah-148v-3570c-4s1...

Comment by John Rambo on March 24, 2014 at 1:20am

I don't see any wonders in here. 
take for example 30x PANASONIC NCR18650B 3400mAh - that will cost you $300, and will give you 25500mAh@14.8V. Most of previous flight records were made with those batteries in particular. 


T3
Comment by Thorsten on March 24, 2014 at 3:24am

There was a cited comment from Graham some days ago (his original comment is missing this information...). Anyway, it was stated there that the cell cycle life of the GEB 8043125 is only 50. Vova or anyone else, can you confirm this?

Comment by Quadzimodo on March 24, 2014 at 3:45am
Vova - That flight must have been hard with no functionng loiter mode.

Thorsten - I too would like confirmation on cycle life of GEB 8043125 cells if possible. Thanks.
Comment by Thijs Sillen on March 24, 2014 at 7:27am

I contacted the manufacturer a while ago and the cycle life is only 50.

The cells are 13 usd each and are custom manufactured for a customer of them.

The newer panasonic cells which are available in china (desoldered from some tesla battery or something) get around 245-255 wh/kg and have a cycle life in the hundreds if not thousands.

Skype conversation with the manufacturer:

[18-3-2014 12:29:46] Thijs: No thank you , I am really interested in high energy density batteries
[18-3-2014 12:30:16] andrew: One more thing I need notice
[18-3-2014 12:30:37] andrew: the cyclelife of the high energy density cells is only 50cells
[18-3-2014 12:30:56] andrew: we customize these cells for special application
[18-3-2014 12:31:07] andrew: 50times
[18-3-2014 12:31:11] andrew: only
[18-3-2014 12:31:47 | Edited 12:31:54] Thijs: so in total 50 cells * 50 times = 2500 cells?
[18-3-2014 12:32:00] andrew: NO, sorry
[18-3-2014 12:32:15] andrew: I mean the cycle life of the cell is only 50times
[18-3-2014 12:32:20] andrew: life span
[18-3-2014 12:32:40] Thijs: so 50 charges and it is dead ?
[18-3-2014 12:32:47] andrew: yes
[18-3-2014 12:32:55] andrew: it is the drawback

Comment by Euan Ramsay on March 24, 2014 at 7:33am

50 cycles??? Woah (if true).

Comment by Daniel Allen on March 24, 2014 at 7:57am

Great video its great to see people trying out new tech. So why not use a wooden prop for higher pitch (Gemfan, Xoar), they have 8+ pitch. Those 5.5 t-motor props you're talking about aren't efficient props from my tests.

I was considering the GEB-8043125 vs NCR18650B since it was a higher power density. However the 0.5-1C and 50 life cycle is a deal breaker. I think I'll try the NCR18650B in a 4S6S formation instead.

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