Yeah you can see lot's of claims for batteries with higher capacities than the OEM batteries, for iPhones and Galaxy phones.... most reviews go "it was great for a few months, and then it died...."
While I'm sure battery technology has improved in the last seven years.... it hasn't improved that much, and it's not going to be cheaper.
But you have it... plug it in and see how it goes. And let us know.... I'm sure other would be interested in getting four days of battery life out of their Passport.
