Originally posted by CRASH
If you did short them together it is very possible you did damage one of the cells.
As someone else asked did you try restarting the charge process? If you did and it still stops at 800 then it probably is a dead cell.
Later,
I had the same exact problems a while back. It could be you have a bad cell or something wrong with the assembly. In my case the Millenium Pro Chargers were the problem and not the packs. I would take the packs that would constantly false peak on the Novak and put them on my GFX (not using the lockout feature) and no more false peaks. When I had the Millenium Pro's every two months I would have to send them back to Novak because they would false peak. Every time I sent them back, they sent me brand new chargers. They would work perfectly for a few months and then start false peaking. So I just threw them up on ebay and bought another GFX...never had a problem since!