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Asked: 2022-05-10T15:57:21+05:30

Charging supercapacitors with reversed polarity

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I bought six supercapacitors and connected them in series to get a total voltage of 16.2 VDC.

The product’s Mouser No is 723-BCAP0450P270S18, Mfr. No is BCAP0450 P270 S18, the datasheet can be found on this link:

The problem is that I applied reversed voltage to charge the supercapacitor bank. The supercapacitors were charged (starting with 10A charging current) until reaching their optimal voltage (2.7 VDC each) and the day after, I discharged them using resistors. This happened three to four times. They do not seem to have suffered any damage and no problem occurred during this procedure, so I would like to ask:

  1. Might the supercapacitors have been internally damaged and they are dangerous to use?
  2. If not, should I keep charging them using reversed polarity or should I apply the correct polarity to charge them again?
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      Electrolytic capacitor polarization is initially set at the factory by applying voltage to form the insulating oxide layer.

      That is why caps have a polarity and these standard supercaps are no different. Reversing the polarity will damage the original insulating layer first and then start to form a new insulating layer with the applied polarity. It is not something that should be allowed to happen, so consider the capacitors damaged, or at least degraded, and they could be unstable and dangerous too.

      Here is also what manufacturer says about reversing the polarity:

      https://maxwell.com/wp-content/uploads/2021/08/Notes_on_Using_Ultracapacitor_Cells.pdf

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