ESC INPUT CAPACITORS

[alan-c]

Hello, endless folk.

I've just bought some Jeti/Hacker 99A r/c speed controllers, used, and two of the three have melted their input capacitor leads. They were sold to me as two working and one not working. I haven't tested them yet because I imagine that could damage the FETs in the ones with melted leads. I'm assuming for now that the "good" one is ok.
Are the ESCs with melted leads already dead?

The original capacitors fitted are 330microfarad 50v which seems low voltage considering the ESCs are rated to 50v. Also the marking on the melted caps is T0628 and T0629 and on the good caps is T0948.
Can anyone explain or comment on these points please?
Based on replies I'll either try to get some money back or buy some new caps.

On the subject of long battery leads, I've built a brushless outboard motor using the C80-100 outrunner and Pentium ESC with about eight feet of battery cable and no problems (running at 600-800 watts).

 

[spinningmagnets]

The Farad size is not an issue, even small ones have enough uF's, you want low resistance (milli-Ohms), and higher amp-capacity.

AJ has had long-term success with his Castle HV-160 ESC using 63V capacitors added to the two red/black power inputs. The specs on the low-ESR capacitors are slightly better if you use a voltage that is lower, and the guys using 44V/48V batteries seem to be doing OK with the 50V capacitors (which may actually survive up to 55V).

The caps are roughly a dollar each, so...maybe just use four of the 63V caps in stead of two 50V? Never have to worry, voltage ripple will be almost non-existant. The 63V caps are twice as large, so that's another reason some guys want to see if they can get away with 50V caps?

http://endless-sphere.com/forums/viewtopic.php?f=30&t=22194&start=45#p382837

16 mOhm, 3.32A, 50V, http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P12393-ND
17 mOhm, 3.50A, 63V, http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=565-1731-ND

 

[alan-c]

Thanks, spinningmagnets, for your reply. While waiting for a reply I decided to solder connectors to the "good" ESC and found that it was not working, just spins the motor for a fraction of a second, unless you disconnect, then reconnect the battery; also does not give an audio signal for the number of cells. In the light of this added to the other faults I have decided to ask for a full refund.
But I did find that, as you said, suitable low ESR caps are cheap enough - and thanks for the link; there are several good threads on here about input caps.
I suppose this thread is over unless anyone wants to comment on the melted leads?