Modification to maximize battery charge?

Has anybody heard of a modification to force the hybrid system to charge the battery at it's maximum rate using the ICE? I'm thinking of something like the EV button that I could activate and tell the system to charge the battery as long as it's within the acceptable SOC limits.

We live in CO and drive in the mtns on a regular basis. A typical mtn highway can be 5-20 miles of continuous climbing and obviously the battery gets discharged part way up the mtn and then the only power is from the ICE. The Prius has great power going up 6-10% grades as long as the battery can assist, but once the SOC drops and and the only power comes from the ICE the power drops significantly.

What I would like to do is force the battery to charge at it's max rate when I'm approaching a long climb so I can extend the distance up the mtn I get with battery assist. I know I will sacrifice mpg, but to be honest I don't care, I want to get up the mtn and not get slowed down.