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Amp Draw
Hey guys. Running a brushless motor in a 4wd, what kind of amp draw can I expect from a 5.5 and a 6.5? I want those new trakpower 3200 saddles but I don't know if they can handle it. I was told that 6.5 pulls an average of about 80-90amps, which is getting close to the limit for the trakpowers.
Thanks Chris
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Chris Browning Larsen's Biscuits Last edited by HVAC25000; 03-09-2008 at 09:27 AM. |
#2
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Which Trakpower saddles? I ran a 5.5R in my ZX5 on Trakpower 4800 saddles and had no issues at all.
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Forgot to mention, the 3200s.
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Chris Browning Larsen's Biscuits |
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I've run a 3200 saddle and sintered 6.5 (Speed Passion) in my B4 and was using 1500 mAh, at most, on high traction astro turf.
I would imagine that so long as you're not a complete animal those cells will be okay for 4wd too. Hope that helps a little.
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Last edited by Dunc; 03-09-2008 at 12:49 PM. |
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The current output of the battery is the 'C' rating of the battery multiplied by the capacity in mAh/1000, i.e. if it's a 25C continuous 3200 mAh Li Po then the max continuous current output would be 25 x (3200/1000) = 80A
I'm not clever, I've just done some research because I wondered the same thing myself. See this link http://www.flyingsites.co.uk/features/lipo.htm Cheers Chris |
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Umm, the discharge capacity of the battery was never in question, that's why I asked what kind of amps the motors can draw, not how many the battery can handle (if you see, I even mentioned how many the battery can handle, 3 hours ago). Basically, you didn't tell me anything I didn't already know, and didn't already say myself. You're right, you aren't clever
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Chris Browning Larsen's Biscuits |
#7
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The Nosram/LRP sintered 6.5's are rated at ~370 watts.
370/7.4 (voltage) = 50 amps (max), assuming the cells can hold 7.4v under load. |
#8
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Good old OHMS law
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Stevie Brew BW-RACING@HOTMAIL.COM http://www.oople.com/forums/showthre...hlight=stegger |
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But is that 370 W electrical input (current × voltage), or 370 W 'brake' mechanical output (torque × speed)?
If it's the latter then the current required will be quite a bit more... |
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Quote:
The 6.5 claims to be 91% efficient, although that must vary with the temperature of the windings/rotor? Lets try 370w power output with 91% efficiency, that'd be 407w input and the remaining 37w released as heat/noise. That gives 55 amps draw, not including esc/power wire resistance losses... To the original question... The 3200's will be fine, in my experience the 3200 gives a similar feel to a good NiMh pack in terms of punch but is lighter |
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