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Battery Help

Old 03-22-2009, 01:27 PM
  #1  
ozflyer
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Default Battery Help

Hi there,
I am new to this hobby and was hoping to get some help.
I recently upgraded an Island hopper with the motor and ESC listed below and was wondering what is the best size LiPo battery to get for increased performance. I am still using the 9.6V 650mah NiMh that it came with, with good results, but was hoping to get better performance with a LiPo
What do you guys recommend?

Brushless ESC
Ni-Mh Battery : 4 - 10
Li-Po Battery : 2 - 3
Internal Resistance : 0.005 ohm
Size : 32 x 24 x 7mm
FETS : 12
BEC : 1A
Current : 18A
Max Current : 22A

Outrunner
KV : 1260
No Load Current / 8V : 0.8A
Operating Rate : 5 - 10A
Peak Current : 12A / 15s
Internal Resistance : 0.1353
Shaft Diameter 3.17mm
Net Weight : 40g

Recommend Model : 200 - 600g
Propeller Range : 2 cells Li-Po - 9 x 7.5, 3 cells Li-Po - 8 x 4
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Old 03-22-2009, 03:39 PM
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Dr Kiwi
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I'd say 3s 1320mAh of at least 10-12C - you'd need to choose a prop to suit - to draw no more than about 10A.

If you got a 15C+ pack I suppose you could go down to 900mAh, but your flight times would be shorter.
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Old 03-24-2009, 12:13 AM
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ozflyer
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Thanks for your help. So if I go with a battery that has too large a C rating will I damage the motor?
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Old 03-24-2009, 12:19 AM
  #4  
gfdengine204
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Originally Posted by ozflyer View Post
Thanks for your help. So if I go with a battery that has too large a C rating will I damage the motor?
Oz,

First off, Welcome to Wattflyer!

No, a higher C rating will actually protect the Lipo pack. The C rating shows you how "hard' or "fast" the pack can be discharged. For example:

a 1000mah pack rated at 10C is rated for 10A discharge. (1000mah divided by 1000 times the C rating). A 15C pack can be discharged at 15A; 20C pack at 20A.

However, most flyers like to have a safety margin to keep from overstressing the pack, and will only fly a pack to 75-80% of it's C rating. So, say we stay with a 1000mah pack, and you need to get 15 amps out of it (based on your motor and prop combo). You could use a 15C 1000mah pack, but you are pushing it to it's limits. If you go with a 20C pack, then you are not stressing the pack to it's max, and it will last you longer (give you more cycles). And getting more cycles means you get more for your money.

Clear as mud?
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Old 03-24-2009, 12:25 AM
  #5  
Angler-Hi
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Originally Posted by ozflyer View Post
Thanks for your help. So if I go with a battery that has too large a C rating will I damage the motor?
The larger the "C" rating, the more "juice" your battery can put out at one given time. Your battery only gives what your motor is wanting. You can never have too big of a "C" rating...too small?...yes.

Now a too big a prop on the other hand can definitely strain your motor, and pull more amps than what it's rated for. That could burn up your motor AND your ESC.
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