keep getting logged out too early

[mcfiredrill]

I have set my expiration time to pretty far ahead:
https://github.com/datafruits/datafruits/blob/05ac109b5557ddd3d737bc4ef21cc176e4b0ac4a/app/controllers/home/chat.js#L27
And I have the proper cookie session store file:
https://github.com/datafruits/datafruits/blob/0e9d6ca2e308da6c55304d9795cbbd733ffae08f/app/session-stores/application.js

Yet I seem to get logged out every few hours or so. Any way to remedy this or a step I missed?