soaked capacitor

flippityflop1

Jan 27, 2009
135
Joined
Jan 27, 2009
Messages
135
i left this capacitor (http://www.digikey.ca/product-search/en?vendor=0&keywords=382LX123M100N082) outside and it rained. it was in an upside down position (as shown in the picture). it was like that as i soldered big gauge wires to it, as i sometimes use it to rectify high currents.

there was very little white tarnish/oxides around the boundaries where the rubber and metal can meet. looks a bit of the metal oxidized due to the 1.5V difference. they happen to trace a path from the negative to positive.

i took it back in as soon as i got out of bed. tested it with 1.5VAC again then +40VAC... seems to rectify just fine.

as a precaution, i peeled off some of the plastic cover and then super glued the metal/rubber boundaries and then applied plasti-dip on it (pic attached).

i measured with my LC meter and it was registering 11mF. labeled as 12mF... 8% deviation, and the specs say 20%, so good.

but i'm still worried about internal shorting... how do i detect this?

View attachment 42234

 
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audioguru2

Apr 6, 2004
12,026
Joined
Apr 6, 2004
Messages
12,026
Your soldering looks bad. It should look smooth and shiny. Did you use plumber's solder? Maybe your soldering iron is too small to solder those big wires.
A shorted capacitor does not hold a charge. Its charge quickly discharges through the short.

Charge it then use a high input resistance meter to measure its voltage with the charger removed. If the voltage stays for hours then it is fine. But if the voltage drops quickly then it is shorted or is very leaky.

 
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