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Old Dec 07, 2014, 10:02 PM
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United States, OH, Norton
Joined Aug 2013
782 Posts
I flew my maiden today of the Easy Star 2 with FPV gear. All went well. The Vector could use a bit more tuning, but right out of the box 2D, 2D Hold, Loiter and RTH worked fine. The motor is a bit underpowered, would like to have a better climb rate but wow!!! I cruise along at 2.5A!
  • SunnySky 2212 980KV
  • GemFan 9x4.7 CF Prop
  • SmallParts CNC Motor Mount
  • EagleTree Vector
  • FatShark Pan/Tilt 600TVL Camera
  • RMRC 1.3GHz 800mw VTX
  • IBCrazy Skew Planner
  • DragonLink MicroRX (that thing is awesome!)
  • RMRC 3s3300 35C Battery

AUW: 1002g, flight time about 50 minutes
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Last edited by jcowgar; Dec 09, 2014 at 04:28 PM.
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Old Dec 09, 2014, 03:16 PM
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Joined Mar 2013
11 Posts
Guys,

Could someone kindly recommend some batteries for the stock EZ2? There's seems to be a big variation in prices from approx 10-30 per batt for what seem like similar specs. I'm planning to order from the UK.

Many thanks!
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Old Dec 09, 2014, 03:23 PM
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Bill0's Avatar
United States, CA, Oceanside
Joined Aug 2010
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Quote:
Originally Posted by CianR View Post
Guys,

Could someone kindly recommend some batteries for the stock EZ2? There's seems to be a big variation in prices from approx 10-30 per batt for what seem like similar specs. I'm planning to order from the UK.

Many thanks!
I use 2200 30 c and can fly almost a hour.
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Old Dec 10, 2014, 04:43 AM
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Joined Mar 2013
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Originally Posted by Bill0 View Post
I use 2200 30 c and can fly almost a hour.
Wow an hour? I wasn't expecting to get that.

Many thanks for your reply - I wasn't sure if 30c was good (I did read up on it but didn't fully understand it).

If there particular brands of batteries people recommend? Or ones to stay away from?

Thanks!
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Old Dec 10, 2014, 07:18 AM
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United States, OH, Norton
Joined Aug 2013
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Originally Posted by CianR View Post
Many thanks for your reply - I wasn't sure if 30c was good (I did read up on it but didn't fully understand it).
It is a rating of how much power the battery can deliver for an extended period of time. 30C means 30 times the battery capacity. So, for the sake of easy math, say the capacity is 1000mAh, 30C means it can deliver 30 * 1000 = 30,000mAh (or 30 AMPS) for an extended period of time.

The higher the C rating, usually the larger/heavier the battery is. So, if you have an airplane that draws at max 10A, a 3300 at 50C (3300 * 50 = 165,000 or 165A) is an overkill. You'd be better off with a 3300 at 10C (3300 * 10 = 33,000 or 33A).

The 10C would be smaller/lighter, thus more runtime. If, on the other hand, your plane can pull 60A, a 3300 at 10C would not be sufficient.

There is also usually a peak or spike current a battery can handle too, you may see 10C/30C as a rating. It can handle a continuous 10C but can spike for very short durations to 30C. Most people I'd venture to say do not rely on the spike capacity. If you need 30C you should get 30C.

Now, if you have a 3300 30C battery (33A) and only draw 5A, you can certainly use the 30C battery, no harm will be done, just a bit overkill that's all.

Do not confuse 30C/25C/10C with battery capacity though. For example, a 1000mAh battery can deliver 1000mAh of power before its empty regardless of it's C rating (30C, 10C, etc...). The C rating is simply how quick it can deliver that power. For example, take a gallon jug of water and poke a needle hole in the top. It can deliver 1 gallon of water, at a very slow rate. Take another gallon of water and put a 3" hole in the top. It too can only deliver a gallon of water, but at a very rapid rate.

You will also see ratings such as max charge rate 3C. That is the capacity times 3, for example 3300mAh * 3 = 9900mAh or 9.9A. That battery can be charged at a max of 9.9A. A battery with a 1C rating (say 3300mAh) can be charged with up to 3300mAh or 3.3A.
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Last edited by jcowgar; Dec 10, 2014 at 07:23 AM. Reason: Added explanation of battery charge capacity
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Old Dec 10, 2014, 07:46 AM
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Ilkley, West Yorkshire, UK
Joined Nov 2008
3,745 Posts
What he said......

Or, to put it simply, the C rating is an indication of the peak current a battery can theoretically deliver, where 1C = the battery's capacity (numerically speaking).

So for a 2200mAh battery, 1C = 2200mA = 2.2A. If it is a 20C battery, it can theoretically deliver a current of (20 x 2.2) = 44A. However, makers often overstate the performance of their batteries, and also pulling the C rated current causes a transient voltage drop which can have your LVC cutting in.

If your peak expected current is 25A, the above 20C battery should be fine. If you are expecting 35A peak, you may be better going to a 25C battery (55A theoretical).

Just my simpleton's view....
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Old Dec 10, 2014, 01:03 PM
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Joined Mar 2013
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Wow thanks so much to jcowgar and the Colonol for the great explanation - much appreciated! I'm always impressed by the helpfulness of people on this forum.

I ended up buying two Turnigy 2200 30C's and these adapters for the stock setup.

Looking forward to getting airborne again soon!
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Old Dec 16, 2014, 05:59 AM
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Italy, Calabria, Calalunga-pietragrande
Joined Jan 2013
194 Posts
Year of Flight - 2014

Year of Flight: 2014 (5 min 4 sec)
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