In the past we had some serious trouble trying to assemble this recharger by hand.
For those starting now, you might consider acquiring
this recharger. From the specifications I suppose it should work just fine with the batteries inside our robots. You can still use our original board design, place only the connectors and hook some wires to a bunch of these rechargers. Each robot has two cells inside, so you need at least two of these rechargers for each robot, total of 12 if you want to recharge 6 robots simultaneously.
Please share your experiences here if you did this or if you tried another similar solution.