2 NiMh in series

I posted this in another part of the forum but figured that this forum was more appropriate and hopefully I will get some more help.

I have an E-Revo, Feigao 8XL, MM ESC, Medusa BEC, standard gearing. Initially, I ran two (brand new) Venom 6cell 4600 packs in series. I was able to experience the power of 14.8V, but it only lasted for 2 minutes - that is no exaggeration!

Attached are the photo's of my setup (series harness). Please help as I'm sure I should get more than two minutes of runtime.

Thanks.

Additionally, I just got a Flightpower 4s 5350 and got ~10 minutes of runtime. This also seems a bit short, but I unhooked the battery from the charger after 65 minutes and I figure it wasn't done charging - am I right?