How much is gasoline mileage reduced by HV Charge?

I did it once for 25-30 minutes on a flat freeway, speed was 70+, I set the B trip meter and averaged 25mpg while charging and driving. EV gauge went from 2 bars to half full (10 bars?). There may be a more accurate way to measure fuel consumption under such conditions. The total trip (700 miles) mpg was 40.

With that limited information, I determined it was basically a wash between the additional fuel used and the EV range gained. I find it difficult to believe, however, that it is possible to run a gas generator to charge batteries and then use that stored energy to propel the car a distance equal to what it would have traveled on gasoline in HV mode. YMMV.

 

I drove about 300 miles and let the battery discharge to about 15% before my destination in late September. When I got to the destination, I found I would not be able to recharge. Over the course of a week I used HV Charge to get the range back a little at a time as I drove to go out to eat, etc. I was pleasantly surprised that it really didn't seem to impact overall economics as best I could tell. I was also guilty of driving in EV mode at the start of a couple of drives, so I used HV Charge to get those miles back as well. I've decided it just isn't a big deal. Honda made it so that the sacrifice in efficiency from using the car to gain some charge in the battery just isn't that big a deal (or at least that is my opinion now based on what I have seen thus far). I was driving on roads during the HV Charge period that had a speed limit of 50 MPH, so that may have helped some to give the engine plenty of room to charge the battery some without struggling at all with moving much from it's desired efficient operation point.

 

My experience is a 10 mile drop between HV and HV Charge

 

I expect the real difference is near zero. The engine is charging the battery and sometimes moving the wheels. This happens regardless of which HV mode you have it in, it just won't turn off until 60% charge in one case. The difference in mileage comes from EV miles vs HV miles, and obviously using HV charge mode goes through gas more quickly than (non-charge) HV, but only because the engine doesn't turn off. You might fill up the tank having gone through fewer EV miles (or even miles at all - if the engine is warmed up and you're waiting at a light in HV (non-charge), it'll turn off and burn battery while you sit there; in HV charge, it is running while you're going no miles at all), so the overall mileage is lower. Re: jdonalds, that's less than 1 mile per gallon. Not much.