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: 13242


Moderator
Comment by Sgt Ric on March 25, 2014 at 5:30am
Of course Vova would have them first... He is RangeVideo!
Comment by vova reznik on March 25, 2014 at 9:22am

Attached is a charge/discharge graph a single GEB 8043125 cell. 

After 95 cycles, the battery has lost 13.75% of its capacity.

This is ideal. You have to take into account the interaction between cells in a pack, and also higher discharge regime.  Anyway, the battery is not' dead' after 50 cycles.


Battery cycle life RV Endurance Batteries

Compared to the usual high rate R/C lipo cell, the new lightweight,  low discharge, GEB8043125  Li-po has a shorter life span.  You can expect to see drop in capacity after 50 + charge/discharge cycles, whereas a standard Li-po will usually last 75-100 cycles before aging and losing some of its’ capacity.  Actually, we have seen some standard Li-po’s go bad (puff) even before 50 cycles. 
 
RV Endurance cells are made by GEB power , which is China’s No.1 battery manufacturer. You can be sure that each cell is thoroughly tested for capacity and discharge ability before being assembled into a pack. The shorter life span of the cells is simply trade off for their ultra light weight. 
 
RV Endurance batteries are used to break records and  we specially designed for  commercial / military applications.  For a hobbyist, 50 charge cycles is equivalent to flying a long range endurance flight every weekend, for one year straight.  You are more likely to crash or lose your airplane before aging its' battery.  Also, consider that battery technology is always advancing , and that in one year , there will be better cells available. If you want to fly farther today, then RV Endurance is your #1 choice.  
Battery cycle life RV Power Batteries

Compared the the usual high rate R/C cell, the RV Power Li-po  generally has a longer life span. The cells are made by Grepower , and are recognized world wide for being very high quality.
Grepower makes cells for brands like Gens Ace. You can expect at least 200 charge/discharge cycles with the RV Power batteries. If you need top of the line batteries for your DJI S800 / S1000, then RV Power is definitely your #1 choice!
Comment by Tipu on March 25, 2014 at 1:30pm

This is snap from excel file,  comparison of few batteries.

Cant upload actual excel file. :(

Price of GEB and Melasta cells are on MOQ 500 (Minimum Order Quantity)

vova reznik If this snap is after 95 cycles, Really not bad. Very good enough after 95 cycles, but someone must be careful about battery getting hotter.

But if someone knows how to make a battery with balance connector, I am sure he wont choose to buy from RV. Because of a bigger difference in price of cell and battery.I am not here for business, but being a hobbyist, its fun to make things yourself. This is what I do.

I have Melasta and GEB batteries, But thinking to try Panasonic NCR18650B.

Comment by Tipu on March 27, 2014 at 11:34am

It seems a new vendor coming with GEB8043125  like batteries.

its www.vipower.biz and they are offering VIP8045120 3.7V 6000mAh cells.

specs are attached.

Anyone know it ?

Comment by Pedals2Paddles on March 27, 2014 at 1:13pm
Many of these are .5C to 1C but are incredibly lightweight. Too bad the low C rating rules them out as flight batteries on a multirotor. I suppose what gives them the low C rating is also what makes them so lightweight.
Comment by John Rambo on March 31, 2014 at 2:00am

For those looking for higher C ratings, EnerPower 26650 4500mAh is something closest one can get: http://lygte-info.dk/review/batteries2012/EnerPower%2026650%204500m...(Dark%20blue)%20UK.html

Comment by Tommy Larsen on March 31, 2014 at 3:33am

This Enerpower is 96.2 grams so the weight/power ration is not that good.

Comment by Tipu on March 31, 2014 at 3:49am

96g for 4500mah ??

Why don't yoiu go for Geb8043125.

I am buying them, awesome weight to power ratio.

Comment by Spike Webb on April 6, 2015 at 4:28pm

anybody making up packs out of ncr18650b panasonic cells? genuine ones?  looking for about 75 ah capacity at 11.1 volts myself for a long endurance fixed wing.

Comment by Tipu on April 7, 2015 at 11:51am

@Spkie Webb

NCR18650b are 46g each and 3.4ah.

I have many 6AH GEB 8043125 cells with me. 80g weight and 2C discharge.

found them batter then NCR18650 in making batteries, charging etc.

have few , about 4 to 6 cells of NCR18650b left, but not satisfy with them.

78Ah 3S battery of GEB8043125 will weigh about 3120g. but if you make 3s battery with NCR18650 75ah battery will weigh 3036.

84g is not a big deal. but my suggestion is to use GEB8043125 cells, that will make life easy for you.

PM me if further help is needed.

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