- #1
artis
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So some time ago I got a bunch of electrolytic caps from a friend of mine who works at a local university experimental laboratory,
the caps have been in good storage (temperature etc) they were sitting some while in my room and now I finally decided to see whether they are still any good.
Some are manufactured in 1983, some in 85 and some in 89, so all are older than 30 years.
8 pairs of 50V 22000uF , two pairs of 80V 15000uF, and two pairs of 50V 10000uF, there are two boxes full of other smaller values like 50v 1000uF and so on.
So what i did is this , I measured the capacitance with a multimeter , surprisingly no capacitors were below their rated capacitance value, some were much higher one was showing 38 000uF.
Then for some days I took a car battery and charged them and discharged them with a low value resistor, charged again and discharged again and so on.
Measured the capacitance values once more and they were all roughly the same as before.
So then I charged every capacitor to around 12.8 Volts (the voltage of my car battery) and left them overnight,
this morning I took my voltmeter and checked everyone of the capacitors.
Some of the capacitors have retained almost all the charging voltage (around 10,11 volts) while others are lower to around 3,4 volts, while a few had only mV left in them.
the question is what does this suggest about the capacitors ? Any commentary is welcomed.
I personally feel that the caps that still have almost all the charging voltage are really good while the ones that lost it overnight are probably still okay (they measured to rated capacitance) but have a higher "leakage" probably due to age?
the caps have been in good storage (temperature etc) they were sitting some while in my room and now I finally decided to see whether they are still any good.
Some are manufactured in 1983, some in 85 and some in 89, so all are older than 30 years.
8 pairs of 50V 22000uF , two pairs of 80V 15000uF, and two pairs of 50V 10000uF, there are two boxes full of other smaller values like 50v 1000uF and so on.
So what i did is this , I measured the capacitance with a multimeter , surprisingly no capacitors were below their rated capacitance value, some were much higher one was showing 38 000uF.
Then for some days I took a car battery and charged them and discharged them with a low value resistor, charged again and discharged again and so on.
Measured the capacitance values once more and they were all roughly the same as before.
So then I charged every capacitor to around 12.8 Volts (the voltage of my car battery) and left them overnight,
this morning I took my voltmeter and checked everyone of the capacitors.
Some of the capacitors have retained almost all the charging voltage (around 10,11 volts) while others are lower to around 3,4 volts, while a few had only mV left in them.
the question is what does this suggest about the capacitors ? Any commentary is welcomed.
I personally feel that the caps that still have almost all the charging voltage are really good while the ones that lost it overnight are probably still okay (they measured to rated capacitance) but have a higher "leakage" probably due to age?