It really surprises me that many more people don't burn their houses down wiring up these batteries.
Your above statement is again, incorrect.
P+ and P- go to the charge port AND P+ should be wired to whatever switch you are using to turn the system on and off. P- should be wired to the ground of your regulator/system.
The batteries should be wired as such:
Battery 1 + wired to B+
Battery 1 - wired to common
Battery 2 + wired to common
Battery 2 - wired to B-