Does the way you regen make any difference to the amount of charging done?

[Feathermerchan]

So there is inefficiency in regen - Electrical, and Chemical
But there are also friction losses which are non-linear - rolling resistance, wind resistance
Coasting minimizes (eliminates) regen losses but also maximizes rolling and wind resistance losses.
Since none of these are linear, I'm betting it will take a model to figure out the best strategy.

For an ICE coasting is probably the most efficient because using brakes wastes 100% of the kinetic energy and at idle an engine uses little gasoline and maybe none if the software cuts fuel altogether during coast.

 

[derotam]

There are two different things being talked about here. The OP's original question as per the words they used is more of interest to me than what people are talking about. The OP's words are asking which braking method generates more power. What is the difference in generation between traveling x distance with your foot fully off the accelerator vs letting off the accelerator to maintain a set regen level until stopped. Yes I agree with Rocky's stated physics but that doesn't account for any regen efficiency curve that the regen equipment on the car has.

When you talk about your Wh/mil over a set distance and how average speed effects that in concurance with the regen method, that is a different answer because you get into the answer changing based on starting speed.

Anecdotally I will say that using the car on autopilot in slow and go traffic has been less efficient(Wh/mi) than me staying off AP and having a longer regen/coast slowdown. But I don't think that answers the question of how much regen was actually generated.

 

[Rocky_H]

There are two different things being talked about here. The OP's original question as per the words they used is more of interest to me than what people are talking about. The OP's words are asking which braking method generates more power. What is the difference in generation between traveling x distance with your foot fully off the accelerator vs letting off the accelerator to maintain a set regen level until stopped. Yes I agree with Rocky's stated physics but that doesn't account for any regen efficiency curve that the regen equipment on the car has.

Yeah, I noticed the discussion seemed to deviate into stuff that wasn't originally asked, talking about long downhills and high wind resistance at really high speeds, like 80+ mph, which didn't seem like the scenario I was picturing. I was thinking more like 45 mph down to 5 mph, flat road, and do you slow down really quickly, like pop your foot off the pedal, and hit 60kW of regen power, or do you just pull your foot back a little, to slow down from 45 to 5 mph with a steady 20 kW or so of regen power. And yes, that would get into the efficiency curves of the motor's regen capability, which we don't have specs for.

 

[Falkirk]

I was thinking the same when I asked the question to start just city driving mostly really is when I noticed the option to do either. I'm happy for the debate and learning from the conversation!

That's the cool part of electric cars I think, there are so many aspects to it that are so interesting compared to a standard ICE car that didn't do anything for me most of my life. Now I'm hooked!

 

[derotam]

Yeah, I noticed the discussion seemed to deviate into stuff that wasn't originally asked, talking about long downhills and high wind resistance at really high speeds, like 80+ mph, which didn't seem like the scenario I was picturing. I was thinking more like 45 mph down to 5 mph, flat road, and do you slow down really quickly, like pop your foot off the pedal, and hit 60kW of regen power, or do you just pull your foot back a little, to slow down from 45 to 5 mph with a steady 20 kW or so of regen power. And yes, that would get into the efficiency curves of the motor's regen capability, which we don't have specs for.

Yeah, but David99 has some interesting data to look at. I might look into getting the OBDII stuff and do some tests...though in reality I will probably never actually get the stuff and do the tests, haha

I did some measurements with my Model S if anyone is interested
most efficient regen speed measured

Interesting data, thanks!

 

[Snow Drift]

A) Abruptly let off the pedal _________________ over a short distance

vs.

B) Reduce pressure on the pedal ___ over a longer distance

Can the amount of energy recaptured be the same if the distance is long enough?

 

[Feathermerchan]

The most energy that can be captured is the total kinetic energy of the vehicle (½MV²)
Several things will prevent 100% capture:
Wind resistance
Rolling resistance
Mechanical to Electrical conversion inefficiency (varies non-linearly with regen amount)
Electrical to chemical conversion efficiency.

My question is what regen strategy results in the most range for a given trip.

 

[David99]

The most energy that can be captured is the total kinetic energy of the vehicle (½MV²)
Several things will prevent 100% capture:
Wind resistance
Rolling resistance
Mechanical to Electrical conversion inefficiency (varies non-linearly with regen amount)
Electrical to chemical conversion efficiency.

My question is what regen strategy results in the most range for a given trip.

Based on the test I did (see my link to the other thread I started) it makes almost no difference if you regen gently over a longer distance/time or regen stronger and shorter.