Correct.

While the wall wart will not harm the LiPo battery ( the wall wart current is way too low and the incorrect voltage doesn't help either... ), it also will not charge it fully nor balance it properly.

The best thing to do is to hook up one of these to a LiPo balance charger.

I recently gave one of these battery packs to a friend as a gift, and I took a balance charger and wall wart 12v supply that came with an EDF and threw that into the box.

He has been quite pleased with the results.

I usually charge mine by removing the backplate from the TX, and with the battery still in place, I charge it through the balance jack using a TC-1030 Team Checkpoint ( aka ICE Intellipeak ) charger.

With an intelligent charger I charge up my packs in far less than an hour and I'm good for the next two weekends.