Can I quickly charge supercapacitors with a power adapter?
You don't want to put caps in series without parallel balancing resistors because otherwise you can never be sure how the voltage between the caps is split up — it would depend on ESR and ESL variance.

For your supercaps, it's worse. You are only 0.2V away from blasting the things, and the currents are so high your balancing resistors had to be very low-ohmic to have any effect. That would be a huge waste of energy.

Do yourself a favour and get a 2.5V converter.