High C vs High mAh

by MIDNCOCO | May 21, 2013 | (6) Posted in Projects

I watch Trent’s (Guy from “MyGeekShow) video I did some calculations in using the new Sony and Panasonic Batteries for my quad applications.  I was looking into using this either in my Hubsan H107C or my Blade Qx.  Both are setup with a HD camera.  Assuming a linear throttle I calculated estimate battery life based on a 5A total load and add the LiPo’s in Parellel to show comparable weight.  In most cases the NCR18650B had double the capacity then the others.  The higher C rating will give you more of dynamic response due to the excess AMPs above the required of 5A.   The NCR18650B being about 1A excess in reserve will feel less dynamic or more like having a stock battery.   For my calculations I figured the best configuration to try this out would be that of my Blade QX using my 808#16 camera.  Although it is slight more weight than my modius with a stock battery, predict although it may feel  sluggish in the air I will be able to significantly increase my flight time.  I will post the video of the results in the second part.

    AMP C Rating Cap mAh weight/cell Voltage/Cell
             
Hubsan stock 6 20 380 11 3.7
Hobbyking Nanotech 13.5 45 300 9 3.7
Panasonic NCR18650B 6 1.764706 3400 45 3.7
Eflite stock 7.5 25 500 14.5

3.7

              Flight time at full C
Series Parellel mAh V AMP Weight  
               
1 4 1520 3.7 24 44   3.8
1 5 1500 3.7 67.5 45   1.333333
1 1 3400 3.7 6 45   34
1 3 1500 3.7 22.5 43.5   4
Discharge at 5A assueming linear throttle
100% 80% 50%
     
18.24 22.8 36.48
18 22.5 36
40.8 51 81.6
18 22.5

36

    Camera Battery   Total Weight Sub for NCR18650
H107C 808 # 16 17 11   28   17
Blade QX Mobius 38 14.5   52.5   -7.5

I also look into using this for my mid-size  450 quad and small FPV planes.  I also did this calculation and against 2200 and 3300 mAh size LiPo’s comparing a combination of series and parallel connections to achieve the required minimum AMPs.  I found that the delightful consequence in doing this to achieve a greater AMPs out was significantly increasing the capacity resulting a greater flight times. 

To give you a background on these batteries, they came from the E-smoker community.  Those clowns you see in the mall puffing electric cigarettes and blowing out water vapor.  Apparently for their applications they need a lot of energy and capacity to do this for people who normal smoke multiply times a day.   Early e-smokers were changing their batteries out 3 times a day.  Even with these higher capacity ones they still do it daily.  In order to fit the product all those batteries are 65mm X 16mm diameter cylinders about 45grams.  The batteries on the market sacrifice capacity for AMPs.  For example there are 6A @ 3400 mAh, 10A @ 2400mAh, and 30A @ 1600 mAh.  Before everyone goes out and buys the 30A battery my calculations show that with the reduced capacity to achieve the higher AMPs it would not give you the best flight time.

    AMP C Rating Cap mAh weight/cell Voltage/Cell
Panasonic NCR18650B 6 1.764706 3400 45 3.7
Panasonic CGR18650CH 10 4.444444 2250 46 3.7
Sony US18650VTC3 30 18.75 1600 45 3.7
             
Hobbyking turingy 44 20 2200 77 3.7
Hobbyking turingy 66 20 3300 111.6667 3.7
             
Hobbyking Nanotech 77 35 2200 66.33333 3.7
Hobbyking Nanotech 148.5 45 3300 105.6667

3.7

series Parellel mAh V AMP Weight   Time
3 4 13600 11.1 24 540   34
3 2 4500 11.1 20 276   13.5
3 1 1600 11.1 30 135   3.2
               
3 1 2200 11.1 44 231   3
3 1 3300 11.1 66 335   3
               
3 1 2200 11.1 77 199   1.714286
3 1 3300 11.1 148.5 317   1.333333
20A Time    
100% 80% 50%
40.8 51 81.6
13.5 16.875 27
4.8 6 9.6
     
6.6 8.25 13.2
9.9 12.375 19.8
     
6.6 8.25 13.2
9.9 12.375 19.8

COMMENTS

Fatherfox on March 26, 2014
as one of those clowns that use an e-cig (i'll save you the details) i know of several battery choices from the mod community. suffice it to say the only thing most of the battery options would give you a decent punch but not much in the way of longevity. going from automotive to rc cars, computers to robotics, solar and power wheelchairs, e-cigs and now getting into fpv, i've seen a lot of batteries come and go. i'd love to see an actual head to head with current tech across the spectrum. i'll give ya an example on my end. i'm using one of my wife's powerchair batteries (group22nf 55ah mx series) hooked up to a 120mm cpu fan and a 15w solar panel to cool my shed in the summer (never needed to plug in the charger running 8-10 hours) as well as using it as an anchor and power supply for my tripod setup and battery charger source for my lipo's. so glad there's so many people here that think outside the box. (even if it is a flying toaster) =^-~=
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OldRCEM-JOEY on March 27, 2014
I'm a little confused, in the paragraph where you mention " to give you a background on these batteries" Which batteries are you talking about? In the beginning of the article you mention the NCR18650B being capacity over AMPs, but this paragraph you mention it the other way around. Also you say that the e-cigs need "a lot of energy and capacity" , not one or the other.


But really based on the numbers you shows for the NCR18650B, this really could be good in small applications, I'm wondering how the scaling would work as you get larger: Efficiency Vs. capacity as your Mah increases relative to the weight. But really, say you used one 3.7v battery to power a mobius or 808 maybe even a gopro you might have better capacity over long flights. i don't know the draw of these items off the top of my head so I'm only guessing.
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deepsouth on March 30, 2014
Thats a cool article and comparison.
With regard to some of the replys, there are batteries and then there are batteries.
Having worked in the renewable energy sector for nearly 8 years now, I've seen all sorts of batteries.
The most important thing when choosing a battery is choosing a battery that suits your application. As an example I have a customer who bought 10k worth of 800 Ah gel sealed batteries. He used 3000watts of solar to charge them during the day and comes home and within four hours he's down to 10% capacity. Why? 800Ah should last him at least a couple of days! We researched his batteries and discovered they were a c10 battery, which means their rating of discharge is over a 10hr period, or they are short discharge high capacity battery, usually used in backup systems where they are required to deliver high power for short periods before mains power is restored.
So we have now changed to a c100 rated battery which has a lower rating of discharge but they can maintain it for 100hrs. He barely touches 80% capacity now with gel sealed 1000Ah batteries. His redundancy is for five days of no charge powering everything he needs.
So when discussing batteries it's important to compare like for like and ratings for ratings.
In 8 years battery technology has skyrocketed and there are some amazing battery technologies filtering down from elite usage to the everyday person. It wasn't so long ago I was excited at Lipo and know we have LiFe and soon we'll have hydrogen self recharging batteries.
It's exciting seeing how much better it makes our flying experience and experiments like this show that sometimes we get into a rut of using what the manufacturers want us to use, rather than using whats better.
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Fatherfox on April 8, 2014
well, just saw a youtube vid claiming 85min quad using the 18650 batteries you have here. thought i'd share. might have to give these batts a try for the long duration tri i'm trying to set up. http://youtu.be/GajlbrAkAK4 using these ebay sourced.
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High C vs High mAh