High Voltage Capacitors
01-29-2013, 04:50 PM
#1
High Voltage Capacitors
I got a question for all you electronic geeks and nerds. I recently desoldered a few capacitors from a high powered Phoenix Gold amplifier for car audio. These caps are rated at 2200 uF @ 50 volts. I know these caps are in a sense temporary "storage for potential energy" but are we able to use this on our (+) and (-) terminals instead of the 10-16 volts capacitors? Would this give a major turbo boost or would this basically destroy the esc and possibly ignite the lipo into a armageddon doomsday inferno. I do know that esc's are restricted to certain operating voltages only. Any help is much appreciated.
Last edited by SuperFastSnail; 01-29-2013 at 04:59 PM. Reason: input photo
01-29-2013, 07:43 PM
#2
The rating on the caps is as follows...
Maximum rated voltage, yours = 50v.
You can hook them upto a 50 volt DC source & they shouldn't pop.
The capacity is rated in Farid, or in your case "microfarids" 2200uf.
It is how much they will hold.
I regularly hook 9400uf to my receiver for stability, but they are only rated 10 volts & are only as big as my receiver.
Caps size is equally dependant on voltage rating as much as is capacity.
As big as those are they would be well over 15,000uf at 10 volts.
They only charge upto what ever the supply voltage is. If you feed them 6 volts that is what they charge to, 6 volts...
Feed them with 12v they hold 12v
Feed them 51 volts & they will likely fail.
I don't have any good ideas for what you have, but they are big & low in capacity.
You can hook them to a 50 volt source, but I don't know of too many of those.
Maximum rated voltage, yours = 50v.
You can hook them upto a 50 volt DC source & they shouldn't pop.
The capacity is rated in Farid, or in your case "microfarids" 2200uf.
It is how much they will hold.
I regularly hook 9400uf to my receiver for stability, but they are only rated 10 volts & are only as big as my receiver.
Caps size is equally dependant on voltage rating as much as is capacity.
As big as those are they would be well over 15,000uf at 10 volts.
They only charge upto what ever the supply voltage is. If you feed them 6 volts that is what they charge to, 6 volts...
Feed them with 12v they hold 12v
Feed them 51 volts & they will likely fail.
I don't have any good ideas for what you have, but they are big & low in capacity.
You can hook them to a 50 volt source, but I don't know of too many of those.
01-29-2013, 08:33 PM
#3
Okay so let me paraphrase that GLwagon. From the math, these capacitors can hold up to 2200uF @ 50 volts OR about 13,000 uF at 8.4 volts and that these caps could possibly be used without fear of damaging the esc and or the battery because the limitations are mainly from the LiPo battery?
Another question is in regards to brushless motors versus brushed motors. In brushed motors we had to put little capacitors to suppress the "noise" created from the arching of the brush and commutator that would cause frequency interference. Since brushless motors are engineered inverted of the brush motors and does not have any point of contact, could we still have the "noise" interference also? If so, how would one attach a capacitor to the "A","B" or "C" wire of the motor? If brushless motors were not producing these "noise" like the brush motors, would putting a capacitor on the motor help "jump" start the motor to have even more torque as oppose to not having a capacitor? Lastly, would putting a huge capacitor on an esc or motor qualify as cheating? I do recall when LRP/Quantum had these tiny esc's but the capacitors on them were awfully huge.
Another question is in regards to brushless motors versus brushed motors. In brushed motors we had to put little capacitors to suppress the "noise" created from the arching of the brush and commutator that would cause frequency interference. Since brushless motors are engineered inverted of the brush motors and does not have any point of contact, could we still have the "noise" interference also? If so, how would one attach a capacitor to the "A","B" or "C" wire of the motor? If brushless motors were not producing these "noise" like the brush motors, would putting a capacitor on the motor help "jump" start the motor to have even more torque as oppose to not having a capacitor? Lastly, would putting a huge capacitor on an esc or motor qualify as cheating? I do recall when LRP/Quantum had these tiny esc's but the capacitors on them were awfully huge.
01-30-2013, 07:58 PM
#5
Tech Fanatic
iTrader: (13)
Capacitors do not scale up in capacity as voltage decreases. If they say 2200uF, they are 2200uF, regardless of current voltage level.
Brushless motors spit microwave-level noise all over everything. It takes significant, complex filtering to get rid of it all. Caps on the 3-phase DC output from the ESC would likely not be able to take the constant pole inversion and pounding. You'd have to use ceramics or large bipolars, and even then it's a lot of high-frequency noise, and you'd have to deal with some significant electrolyte outgassing (can expansion/explosion). Caps go on the source side, not the output side.
If you're looking to get big surge currents into the ESC, you'd be best off looking at Ultracapacitor tech, values in the several farad range. However, as our friend IČR tells us, more amps means more heat. It could do interesting things to an ESC.
Ultracaps are expensive, so I'm going to take a wild guess at that's why we don't see them on the input lines of our ESC's. They are also pretty big.
Brushless motors spit microwave-level noise all over everything. It takes significant, complex filtering to get rid of it all. Caps on the 3-phase DC output from the ESC would likely not be able to take the constant pole inversion and pounding. You'd have to use ceramics or large bipolars, and even then it's a lot of high-frequency noise, and you'd have to deal with some significant electrolyte outgassing (can expansion/explosion). Caps go on the source side, not the output side.
If you're looking to get big surge currents into the ESC, you'd be best off looking at Ultracapacitor tech, values in the several farad range. However, as our friend IČR tells us, more amps means more heat. It could do interesting things to an ESC.
Ultracaps are expensive, so I'm going to take a wild guess at that's why we don't see them on the input lines of our ESC's. They are also pretty big.
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