Just did some testing. While playing a game and pulling 22w, the battery says about 4 hours. While playing a game with a partially depleted battery pulling the full 40w, it says 2hrs.
If you limit the power you will obviously be able to stretch it quite a bit. Overall, quite a bit of extra playtime.
how much extra charge does it give you on the deck?
Just did some testing. While playing a game and pulling 22w, the battery says about 4 hours. While playing a game with a partially depleted battery pulling the full 40w, it says 2hrs.
If you limit the power you will obviously be able to stretch it quite a bit. Overall, quite a bit of extra playtime.