Capacitor requirement?

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MrTitanium

Speak softly and carry a big stick.
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Arrma RC's
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Rather new to electric RC and was wondering why some are running externals capacitors. Why? How does one know if they need and which ones and where to install them?

Please use Layman’s terms ?
 
I added them to one of my trucks due to the esc logging telling my my voltage ripple was high (mmx/2200kv). Since I run the same/similar motor/esc in another truck (mmv2/2200kv), I made one for it as well. Then just for fun, I put it on my blx185/2050kv in my outcast.

The before and after ripple voltage was much better with the pack than without. I just used what I saw others make their packs out of. Low UDR (EDR... can't remember) 1800uf caps, 6 in parallel.

The ripple on my mmx went from 3v+ to <1v. Which according to castle means my esc isn't working as hard with the cap pack.
 
Typically is you are running aggressive gearing (Speedrun use) then it pulls more amps for extended periods of times. The cap packs reduce ripple voltage, which the primary issue is additional stresses the ESC.

In Layman's terms:
Capacitors function to "absorb" voltage spikes and output power when the battery voltage "sags" low. This will smooth out the ripple/ oscillations in voltage supply depending on the load. Ultimately they do not output much in the way of amperage but in the data logs on Castle ESCs I have seen a significant reduction of ripple when I run an array of capacitors totaling 6000uF or more.

Especially with Castle ESCs exteded periods of ripple voltage can lead to failure.
From my experience the HobbyWing ESCs seem to be more resilient to this sort of abuse.

Soooooo if you are not geared to the moon and or running the BLX system or HW you should be fine. I routinely run the BLX185 at 90+mph with zero issues in factory configuration.(aka no external cap pack)
 
FWIW, I was running 4S in my savage flux hp with the MMX/2200kv system in it and wasn't geared to the moon. Actually 1T less on pinion vs stock. I had sent my data logs to Castle to see if they could tell me why it seemed to be rebooting repeatedly on me throughout a run and they mentioned that my ripple voltage was bad and would likely lead to an early failure of my ESC. So to avoid cooking the most expensive piece on my truck, I spent a few bucks and made the cap pack. Then I figured since it helped so much on the MMX, why not spend a few more $ and make one for my other castle esc and I went crazy and made a 3rd for the outcast stock esc.
 
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FWIW, I was running 4S in my savage flux hp with the MMX/2200kv system in it and wasn't geared to the moon. Actually 1T less on pinion vs stock. I had sent my data logs to Castle to see if they could tell me why it seemed to be rebooting repeatedly on me throughout a run and they mentioned that my ripple voltage as bad and would likely lead to an early failure of my ESC. So to avoid cooking the most expensive piece on my truck, I spent a few bucks and made the cap pack.

I believe it tends to be more commonly "necessary" on Castle ESCs.
Not that it wouldn't help on other ones, but Castle seems to have failures due to ripple more often.

With that said the MM2 took some abuse with no issues. (no data logging)

I have personally abused the BLX185, and Max5 with no external capacitors and never missed a beat.
 
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