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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