I emailed x-treme and told them:
"I have found that the side of the battery has a gap and it looks like it either bulged out or they put the bottom part of the casing over the top part when the edge was supposed to be under that. I have hit the low voltage cut off once because the needle moved when I was accelerating but went back to full but I guess when it goes down to far while accelerating that means its going to die."
When the B.M.S. (battery management system)inside the battery case detects a faulty cell it will cut power output from the battery to prevent damage to the rest of the pack.
The B.M.S can also be faulty and cutting power prematurely or not at all.
Unfortunately the manufacturer does not supply us with replacement cells or a replacement B.M.S. so the only option is to replace the complete battery pack.
In your case it sounds like the L.V.C. is too low resulting in over discharging your pack and damaging the cells.
I recommend inspecting the battery, If it is distended it should be replaced.
The battery pack has a one year warranty, if you are within this time period please forward your purchase information and I will send instructions on battery replacement."
Here's pictures of my battery, the second one is when I put it back in, I opened it upside down so I didn't know the exact place to put the foam, how does this battery look and how well is the foam placed? I put one long strip on the top and closed it, it still kinda had a bulge on the side but the battery didn't have problems fitting.
Here's the casing where the edge came out.