Where do i get flux?

That charger cost a lot plus i would have to buy the 12V power supply. Do they have any twin chargers like the super brain 977 for high cell counts.

I had a 40 Watt iron and a 100 watt soldering gun from Radio Shack. Neither worked and I thought it must be tough to make a good set of batteries. MetalMan confirmed these weren't good enough from the problems I described. I bought the $10 60Watt soldering iron and resin core solder from my LHS. Works well! For reference, the iron is Hobbico and the solder is Kester rosin core with non-corrosive flux.

the charger isnt really expensive for the specs but the new 989 is another charger to look at. its ac/dc charges lipos, 20 nimh and the whole shabang...

So was it the solder that made a differance? I can never ger the stuff to stick to the battery guess i need some sand paper.

A little flux on the battery then a good soldering iron with solder will work. I use a 100 watt iron myself. I have put 13 batteries per side of the gorilla chassis. Before you get to far you need a charger. I like to discharge my cells before soldering to. .9v per cell is fine for discharge.

I doubt the 23W iron you have will work. The 40W iron I had couldn't even separate the 7cell EMaxx style packs so I could make them into flat packs. The iron was the important item for my situation. I just used the corner of a flat blade screwdriver to scuff the faces I was soldering. As mentioned, apply a dab of solder on the battery bar and the the battery first and then heat is only needed to finish the solder joint.