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Old 10-10-2001, 09:26 PM   #16
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Wa, There is different Capacitor that we should use?
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Old 10-10-2001, 11:49 PM   #17
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It would further improve the efficiency, but be careful. The capacitance is not the key figure, but the internal impedance at Mhz range, so don't just put any capacitor to your Cyclone. You definately need a high frequency type.
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Old 10-11-2001, 09:17 PM   #18
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thanks JesseT. how do i now if its a high frequency type? i plan to use a Rubicon brand capacitor with the ff. specs: 6800mf, 10v, 105 degrees C, and a label that says MH 09

TFR: novak specifies the particular capacitor that comes with the esc as the one you should use. but i just want to experiment with another. other guys in our track are using different capacitors.
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Old 10-11-2001, 09:28 PM   #19
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OH...okok
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Old 10-11-2001, 11:19 PM   #20
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The Rubycon MH is a general purpose (low cost, not good at anything) capacitor, that has a low impedance only to some hundreds Hz. If you use a better capacitor like XL, ZA, YXG,...etc. you will get over four times more effect with same uF and V values. The speedo needs a capacitor that goes up to Mh and more.
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Old 10-12-2001, 08:27 AM   #21
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thanks im just gonna look for those brands you mentioned. for the meantime, i think ill just stick to the stock capacitor.
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Old 10-16-2001, 08:17 PM   #22
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Got a quick question...

If the Power Capacitor is put on the Cyclone...i heard ppl say that the Cap will "eat" up the batteries life?
is that true?
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Old 10-17-2001, 12:14 AM   #23
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I heard this for the first time now and.... hmmm... I think it's rubbish. Is there an explanation of why this would happen?
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Old 10-17-2001, 06:00 AM   #24
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Well, a capacitor does store small amounts of energy, But i don't think its large enough to even affect runtime by a second... prolly mili-secs if it does. I'm not sure though... I don't think it would..
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Old 10-17-2001, 06:14 AM   #25
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A capacitor can't eat up batteries. The battery capacity is far superio compared to a capasitor.

A 3000 NiMh got around 0,3 Farad. The capacitors used on ESC's is around 4700 micro Farad. So there's asomething like factor 1000 in difference. Besides, when the capasitor is fully charged, it don't draw any more current. And when the car accelerate, the capacitor deliver what's stored to the motor.

A kind of conclusion: The story about ESC capacitors eat up batteries, is rubbish.
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Old 10-17-2001, 06:41 AM   #26
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What makes you say the Nimh has 0,3F capacitance??? How do you measure that? And your statement that acceleration eats up the charge from the cap is dead wrong. Period. That is not how the capacitor works. It is not an energy reserve for accelerations!
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Old 10-17-2001, 02:42 PM   #27
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Sorry, my bad...
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Old 10-17-2001, 11:35 PM   #28
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Just to compare energies:
If a battery has 3000mAh at 7.2V that means it can supply 3A for 1 hour (3600s) at 7.2V. This leads it to having an energy of 77.760kJ.
If a capacitance has 2200uF and it's loaded to 7.2 V it has an energy of E=(1/2)*C*U^2=57.024mJ.
So the energy ratio is 1363636. Over a million...
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Old 10-18-2001, 03:48 AM   #29
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Listen to Charlie, I dont think he would be where he is if he didn't know what he was talkin about. Whats-up Charlie?
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Old 10-18-2001, 04:02 AM   #30
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Charlie, are you really really sure about your statement on the schottky earlier? On free spin the voltage generated is of the same polarity than the one fed from the speedo but the shottky is reversed. On the other hand, when feeding current from the speedo to the motor (on pulse mode of course), the shutting-down period would generate a negative pulse from the motor and this would effectively be absorbed by the shottky. Does this make any sence to you?
BR/ JesseT.
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