[glossolalia]

It makes sense if you think about it. If you didn't accelerate and depending on how long of a downhill stretch your battery would become full quickly. Once it becomes full your engine fires up to burn off the regenerated energy instead of storing it in the battery. By accelerating when needed you're preventing the battery from reaching max capacity and allowing yourself to coast down in EV mode as long as possible.

The scenario you’re describing also makes sense, but that’s not what was happening in this case. Most downhill stretches lasted 30 seconds or less in my case, so the battery never reached past 75% full, whether I coasted or gassed and banked.

After observing the fuel economy reading for a few months I eventually realized that the most emphatic MPG gains happened after stretches of downhill + regen, so I experimented with artificially making that happen whenever I could and that was the result.

 

[andrew28]

Yeah, I had to edit my original post.

Edit: I think I mis-read what you wrote above. My guess is that you're regenerating energy at a higher rate than using when accelerating depending on how steep that downhill is.

 

[glossolalia]

My guess is that you're regenerating energy at a higher rate than using when accelerating depending on how steep that downhill is.

That would be my guess as well. Does accelerating on a downhill somehow create more bankable energy than it uses? This seems to violate some kind of law of physics 😂

 

[andrew28]

Well gravity plus your acceleration is pushing you downhill faster. The regenerative braking increases the rate of recharge the faster you're going. At least to a certain point cause Honda definitely set a threshold to prevent the battery from overheating. So in the end you're most likely making more energy than using on that stretch.

 

[Moviemike]

Wow. What a great idea! I'll have to try it!!

My thinking is that the small amount of energy used to accelerate gives a much greater than usual speed increase, due to gravity's extra push. Thus, as the braking begins you got much more energy coming out than was put in. The mpg increase comes from more efficient capture of the potential energy located in the cars' movement from top of a hill to the bottom.

Another possibility is the mpg increase for most of the trip was due to a tail wind, and not the downgrade. Possible I suppose, but I prefer the other explanation.

 

[glossolalia]

The mpg increase comes from more efficient capture of the potential energy located in the cars' movement from top of a hill to the bottom.

Yep, that’s my guess too. Seems that downhills are a sort of “multiplier” of any acceleration you put in. Presumably there is a point of diminishing return; I wouldn’t expect that flooring it on a downhill would be very efficient, but a light tap goes a long way for very little cost.

Another possibility is the mpg increase for most of the trip was due to a tail wind, and not the downgrade. Possible I suppose, but I prefer the other explanation.

I was watching the mpg gauge pretty closely. Performance was pretty standard for the entire trip, except for the very noticeable bump after using the above strategy. Very interesting indeed!