Big blue capacitor of Quantum Competition 2 ESC
10-25-2004, 04:44 PM
#1
Big blue capacitor of Quantum Competition 2 ESC
What does that big capacitor do?
10-25-2004, 04:53 PM
#2
I wouldn't mind knowing the answer to that one!
10-25-2004, 05:00 PM
#3
Your best bet is to do a search. i personally have posted about this in 3-4 different threads.
First off, it is not necessary on any LRP ESC. But, in short, the capacitor stores energy from the battery. This allows for more punch. The capaciter also keeps the temp of the ESC cooler and helps with interference problems as well.
You cannot use any capactor on any ESC. The capacitor you use must match the speed that the MOSFETS in the ESC open and close.
First off, it is not necessary on any LRP ESC. But, in short, the capacitor stores energy from the battery. This allows for more punch. The capaciter also keeps the temp of the ESC cooler and helps with interference problems as well.
You cannot use any capactor on any ESC. The capacitor you use must match the speed that the MOSFETS in the ESC open and close.
10-25-2004, 05:15 PM
#4
Tech Apprentice
There are alot of theories surrounding capacitors. Most ESC companies use them to smooth out voltage spikes (which can be harmful) created by the high switching rates in most modern ESCs. This setup does offer a few side benefits (more mid-range punch, helps with glitching and helps the ESC run cooler). Most guys think they are used only for more punch, but that's a big misconception. When choosing one you should always use what a manufacturer recommends. Some guys think you can run down to the local Radio Shack and buy whatever to save money, but then wonder why their speedo is eventually toasted.
10-25-2004, 05:50 PM
#5
sounds like the $30 price tag would be worth picking up the cap. set.
10-25-2004, 06:57 PM
#6
Originally posted by killingtime
sounds like the $30 price tag would be worth picking up the cap. set.
sounds like the $30 price tag would be worth picking up the cap. set.
Too be honest, YES!! You should be albe to pick up the LRP World's kit for around $25.00. It comes with 2 capacitors (1 large and 1 small depending on your need), plus a heatsink for the ESC. It looks better than the radio shack/Novak ones and there is no chance that you will fry your $180.00 ESC because you tried to save $5.00.
Remember, it is not even necessary to run a capacitor with LRP ESC's. The only reson i run one is to prevent glitching.
10-26-2004, 11:12 AM
#8
Thanks for the info, also thanks to raceblast for posting a question I had for awhile
10-26-2004, 05:09 PM
#9
What about running two capasitors? i have a GT7 and i'm about to get a GTX so would two capasitors give me more punch or is it a waste
10-26-2004, 05:22 PM
#10
You most likely won't be able to fill both capacitors. Caps work bets when you can fill them completely then dump them while you're running. If you can't fill one, you'll be wasting weight, room and possibly balance by runing a second. If you want to run two, just get two smaller ones than the one big one you've got.
10-19-2005, 11:12 PM
#11
Tech Regular
anyone know if we can use the Novak Power Capacitor 8200mF #5673 on the QC2?
10-20-2005, 02:40 AM
#12
Tech Addict
My 2c in this hot subject . Trust me I'm electrician or was it politician .
Capacitors store and release little energy VERY fast.
If connected across the batteries the effect is that the voltage into the ESC is slightly higher under full throttle from dead stop, that can prevent glitching. I have no idea how it could improve midrange, but maybe it does by allowing some ESCs to work slightly differently.
If connected into the receiver it can prevent glitching and make your personal transponder more reliable, especially with some combinations of ESC and digital servos.
If you never get glitches and your PT counts perfectly you don't "need" capacitor.
Capacitors store very little energy so you'll need a big one.
Capacitors charge up to the voltage applied to them, no more. They charge fully in less than millisecond (1/1000 of a second).
There are hundreds of capacitor types with different parameters. What you'll "need" is the liquid type in a small bucket, (I don't remember the english name) that has high capacitance, usually >4700uF, low voltage <16V (6.4V is fine for receiver capacitor) and low ESR (that's the tricky part. Most personell at Radio Shack have no idea what this means. Lower ESR means it works faster. ). You don't need to buy the capacitors that your ESC manufacturer sells. Electronic equipment shops should have higher quality japanese capacitors at lower prices.
. Trust me I'm electrician or was it politician . Capacitors store and release little energy VERY fast.
If connected across the batteries the effect is that the voltage into the ESC is slightly higher under full throttle from dead stop, that can prevent glitching. I have no idea how it could improve midrange, but maybe it does by allowing some ESCs to work slightly differently.
If connected into the receiver it can prevent glitching and make your personal transponder more reliable, especially with some combinations of ESC and digital servos.
If you never get glitches and your PT counts perfectly you don't "need" capacitor.
Capacitors store very little energy so you'll need a big one.
Capacitors charge up to the voltage applied to them, no more. They charge fully in less than millisecond (1/1000 of a second).
There are hundreds of capacitor types with different parameters. What you'll "need" is the liquid type in a small bucket
, (I don't remember the english name) that has high capacitance, usually >4700uF, low voltage <16V (6.4V is fine for receiver capacitor) and low ESR (that's the tricky part. Most personell at Radio Shack have no idea what this means. Lower ESR means it works faster. ). You don't need to buy the capacitors that your ESC manufacturer sells. Electronic equipment shops should have higher quality japanese capacitors at lower prices.
10-20-2005, 03:09 AM
#13
Since everything is explained in detail and quite well already, I only want to add one thing which was wrong in here. 
A power-capacitor will not make the speed-control run cooler, if any difference occurs the speedo and the motor will get slightly hotter when a capacitor is used due to the slightly higher average current.
Btw, the capacitor does "help" during the partial throttle operation of the speedo only! It basically smoothens out the battery voltage, lowers the batteries internal resistance slightly and therefore the pack should in theory stay slightly cooler!
The manual for the worlds-option-kit is available for download on our (LRP's) website.
A power-capacitor will not make the speed-control run cooler, if any difference occurs the speedo and the motor will get slightly hotter when a capacitor is used due to the slightly higher average current.
Btw, the capacitor does "help" during the partial throttle operation of the speedo only! It basically smoothens out the battery voltage, lowers the batteries internal resistance slightly and therefore the pack should in theory stay slightly cooler!
The manual for the worlds-option-kit is available for download on our (LRP's) website.
10-20-2005, 05:14 AM
#15
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Originally Posted by qwerty
anyone know if we can use the Novak Power Capacitor 8200mF #5673 on the QC2?