Here's an idea or suggestion for a future Volt upgrade: How about this 5th Mode?: this Mode would be entitled "Hold & Charge", or something like that. This mode would allow the ICE to run more actively resulting in increasing the charge on the battery all the way up to a full charge. For example, while driving down a long grade, instead of the engine turning off it would continue to run at perhaps something like 3,000 rpm to charge the battery. Same at a stop. I wonder if anyone else has ever thought of this?? I don't see a downside to this, 'tho perhaps there is.