Pre-made parallel connectors... DODGY.

[londonguy]

Check this out, this connector came from a pre-made parallel cable. It just popped off. Bad cold soldered joint, no solder on the cable.

[papa_lazerous]

I've bought ready made cables before and had cold soldered joints.  You are best getting all the gear and a good soldering iron and just doing it yourself.  I just finished making a few cables up for parallel charging and it only took 20 minutes.  I now have a pair of 4s 5000mah charging at 2C in parallel.  that means my charger is kicking out 20Amps I wouldnt trust any pre bought cable on that kinda current as there are no second chances