Battery life is about the least meaningful spec there is, and it's insanely difficult to calculate. That and it's a small company so I'd imagine that'll just open up liability.
They do list the battery as 53.28Wh however. Let's do some back-of-the-envelope.
At 2.0GHz the 4750HQ TDP is 47W. Chipset TDP is 2.7W. SSDs are damn near negligible (typically a few mW idle, less than 1W when active, but they sleep/wake very very fast so they're mostly always idle). I couldn't find a datasheet on their panel, so I'm going to guess the display consumes around 5W at full brightness. RAM maxed out will cost around 3-6W.
Assuming awful power management (or just running the thing full bore), you're looking at a worst case of somewhere around 45m to 1h. Assuming decent power management (5W idle with screen on at less than full brightness) and occasional spikes due to light use you're looking at 8-10h, or 6-8h just to be safe if I was way off about the display. If you're really worried about it, the extra battery is very well priced at $95.
Edit: Nevermind - see a comment above that lists 3-4h of battery life.
I realize that the estimates aren't hard numbers, but if (e.g.) Apple estimates that the MacBook Air has 11 hours of battery life, I expect not to generally get 1 hour of battery life.