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Old 01-17-2007, 07:08 PM   #16
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I have mine on the pos leading to the motor and neg to the batt. The idea, is that when an excessive draw occurs, the cap dumps its load preventing a voltage drop from the batts from causing a dip in radio reception nad motor performance.
electronics god uses a very good diagram to explain this on his ebay sale site. i have used his 10,000mF caps in the past. Not on the most recent app since it was to big for spot assigned for it. Using a Much More cap,, slightly lower storage but seems not to limit me to a noticeable amount.

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Old 01-18-2007, 06:42 AM   #17
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I asked similar things about 1 week ago here after thinking the same;

Nerdy Question On Exact Function Of Power Cap's?]

Nerdy Power Cap Question on another forum..

Although you may feel extra punch, this is due to the caps effect on the ESC, not the motor.

Charge a cap up then stick it across the terminals of the motor, I bet it probably won't even twitch let alone get 'boost'

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Old 01-18-2007, 07:04 AM   #18
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From what I've gathered the capacitor is more for higher out put motor's in an attemp to keep the speedo cooler. And make the out put of the speedo more responsive. When I ran stock 27 or 19 turn I never ran the capcitor. The speedo never got hot enough. You can get pretty high tech when it come's to speedo's and The capacitor is more of a speedo protector, more than a benefit to the motor out put. 27 or 19 turn I would use it. I would recommend trying it both way's though. If it feel's like the speedo react's faster it will seem punchier. Exsperiment, exsperiment. QC2 Speaking.
Honestly I would say it would have to help in stock 27 or 19 turn.
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Old 01-18-2007, 07:26 AM   #19
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A capacitor is like a temporary storage of energy when high amounts of energy are needed in an instant the cap supplies it. So what happens is when you go to punch the throttle not only do you have the battery supplying power to the ESC but you have the Cap as well. Reason this is useful is that your battery can't supply the energy as quick as the ESC wants it, but the capacitor and the battery can.

You will see capacitors used in large car audio systems, this is for the same reason. You will notice that people with out caps alot of times have dimming headlights that dim when the music hits hard. Thats because there is not enough energy quick enough. With the correct size capacitor in place your headlights will not dim and sufficient power will be supplied for those high amperage hits.
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Old 01-18-2007, 11:15 AM   #20
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We're getting somewhere here.. I know all about the car audio aspects, but most capacitors I've messed with as far as that, have been connected into the power wire alone.. no ground... Only a few had needed grounding. So am I to assume I hook this up the same way? + to power INTO the speedo? and - to the Negative BATTERY wire? Rather than connecting it to the motor at all?


And he is right for those who are scratching your head. The capacitor in a car audio installation is there because it can 1. Deliver power quicker than the battery due to lower internal resistance.. and 2. It helps filter out remaining "Ripple" caused by the alternator switching AC into DC during rectification, which is not caught by the battery.

I got a 97 on my MECP Certification test. Yet I still cant figure out for sure if the capacitor info carries over to these little cars in the same way. Seems to.
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Old 01-18-2007, 02:23 PM   #21
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Quote:
Originally Posted by BadCarmaNY
We're getting somewhere here.. I know all about the car audio aspects, but most capacitors I've messed with as far as that, have been connected into the power wire alone.. no ground... Only a few had needed grounding. So am I to assume I hook this up the same way? + to power INTO the speedo? and - to the Negative BATTERY wire? Rather than connecting it to the motor at all?


And he is right for those who are scratching your head. The capacitor in a car audio installation is there because it can 1. Deliver power quicker than the battery due to lower internal resistance.. and 2. It helps filter out remaining "Ripple" caused by the alternator switching AC into DC during rectification, which is not caught by the battery.

I got a 97 on my MECP Certification test. Yet I still cant figure out for sure if the capacitor info carries over to these little cars in the same way. Seems to.
How much current does a car audio amp setup take, one that will dim the lights?

You also need to remember that the current drain from car audio equipment will usually vary dpending on the sounds & frequencies being produced etc. They are never constant.

Our motors are far more regular in what they demand from the the speedos.

What size are the caps for car audio, 1 farad or higher?

Despite using a lot of current in our application (60A in mod?) the caps we use are 1000 to 4700 microfarad, that's 1/1000th of the capacity of the car audio version. Surely if we are providing a 'boost' we would all be advised to stuff the largest cap we could find in them.

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Old 01-18-2007, 02:58 PM   #22
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Depends on the cars electrical of what will dim lights. 1 farad is the most popular but I have seen them up to 10 farads.

As for ground, definitely ground, I have never seen an audio setup that doesn't need the cap grounded.

About the constant speed on the motors. It is true that the capacitor is not useful during constant speeds, they are used under hard acceleration which is usually as you come out of corners. Remember you spend 80% of your time in the corners so whatever gets you around them faster will help you win the race.
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Old 01-18-2007, 03:59 PM   #23
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Quote:
Originally Posted by Skiddins
How much current does a car audio amp setup take, one that will dim the lights?

You also need to remember that the current drain from car audio equipment will usually vary dpending on the sounds & frequencies being produced etc. They are never constant.

Our motors are far more regular in what they demand from the the speedos.

What size are the caps for car audio, 1 farad or higher?

Despite using a lot of current in our application (60A in mod?) the caps we use are 1000 to 4700 microfarad, that's 1/1000th of the capacity of the car audio version. Surely if we are providing a 'boost' we would all be advised to stuff the largest cap we could find in them.

Skiddins

Ya, car systems generally wont see lights dimming unless you reach 75-80% of the alternators capacity.. i.e. You have a 100 amp alternator, and are using 75-80 amps. 90% Capacity will cause permanent damage to the alternator.. A capacitor is only about a 10% fix.. so without cap, you're using 75-80, with you're at 65-70.. And, it's only good for the initial bass-notes.. Bass, because that takes the most power to make. You car, if it has 100amp alternator.. is designed to use it. If you're running at night, with the heat on, your rear defroster, all lights, and your wipers, and STOCK radio... that's the max your alternator can handle.


So the r/c will react in the same way, I guess... first hitting the throttle, it wont strain the battery so much, and it will have instant power to the motor.


Ok, so I think I got my answer.. I need to hook it between the pos. and neg. battery terminals going into the speedo..

Thanks all for the help!
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