Going with cheap Chinese polysilicon solar cells over Powerfilm. The difference between the two in weight is: polysilicon – 3.75 g, Powerfilm is 6.7 g. The cost difference is enormous. The polysilicon is incredibly fragile. The flat connecting wire is called “tabbing” wire and comes pre soldered. I tried using a soldering iron and found it like working on potato chips. I moved on to solder paste with a hot air tool and am getting great results. The problem is once I get everything put together, I inevitably break a cell. I need to figure out how to get from workbench to launch without breaking it.