Copied from jglopic member of Hyundai-forums
"Has anyone played around with the manual mode of the gear shifter in the HSH? I have started to do so a little, and I have reached an interesting discovery.
I do a good bit of my commute at 45 mph, and there are several areas around my house limited to 30 and 35 mph. I have noticed previously that even when cruising at steady speed in all these areas, the hybrid system barely charges. The other day, at 30 mph, I popped the gear shifter into manual, and it was holding 4th gear. I dropped it to 3rd, the econ indicator barely moved, and the battery started charging more rapidly, thereby engaging EV mode much more often than if the transmission were in D.
Today on my way to work, I was cruising at 45 mph. Going into manual mode, the transmission was in 6th gear. I dropped to 5th, and again the battery started charging much faster. When it went into EV mode, the battery also discharged faster than normal. I then let the battery recharge in 5th, then kicked the transmission to 6th when EV mode re-engaged. I found that I could go about as long in EV mode as it took to charge the battery between EV modes. That's right, I was in EV mode almost 50% of the time!
Normally on that stretch of my commute (4-5 miles), I get one decent stretch of EV mode while cruising at 45. I got three today."
I think he is on to a great hypermiling technique.