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06-02-2011, 09:38 AM | #1 |
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2 Electric questions - amperage
Q1: Supposing I have an electric plane powered by a 5s lipo and I replace the battery with a 4s lipo, how will the amperage be affected? Does it go up or down?
Q2: Supposing I have an electric plane using an APCE 12x6 propeller and I replace it with an APCE 11x7 propeller, how will the amperage be affected? Does it go up or down?
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06-02-2011, 09:57 AM | #2 |
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Re: 2 Electric questions - amperage
1) If everything else remains the same - battery capacity, speed controller, motor, prop, - the amperage should go down because the motor will be spinning slower. you should see a 20% decrease in amperage and prop rpm
2) this would depend on the prop itself. If they are similar props, ie apc thin electric, them amperage should be a little lower with the 11-7. Prop diameter affects amperage more drastically than pitch. In my experience, you can go from a 12-6 to a 11-8or-9 and get similar amp draw. Hope this helps
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06-02-2011, 10:07 AM | #3 |
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Re: 2 Electric questions - amperage
DirtDr - it helps for sure, thanks a lot.
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06-02-2011, 05:52 PM | #4 | |
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Re: 2 Electric questions - amperage
Quote:
Going from e.g 2 to 3 cells increases current by factor (3/2)² = 2.25 (worst case). Vriendelijk groeten Ron Last edited by ron van sommeren; 06-13-2011 at 08:30 AM. |
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06-03-2011, 11:51 AM | #5 |
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Re: 2 Electric questions - amperage
Thak you for the answer Ron.
Now I have a modification to question 1: Supposing I have an electric plane powered by a 5s lipo and I fly the plane at half throttle with 50Km/h using X amperes hour - then I replace the battery with a 4s lipo and fly the plane with 50 Km/h, probably at the different throttle position, how will the amperage be affected? Does it go up or down? Will X go up to compensate the voltage drop and deliver the same power to the motor?
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06-03-2011, 02:00 PM | #6 |
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Re: 2 Electric questions - amperage
X will go up.
for the sake of argument lets say it takes 600 watts to fly a certain speed. Watts (power needed) is voltage times the amperage drawn. again for the sake of argument let's take the voltage of a fully charged lipo. 5 cell 21 volts. 4 cell 16.8. 21 volts divided into 600 watts equals 28.5 amps. 16.8 volts divided into 600 watts equals 35.7 amps.
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