mkhuffman

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I have seen so many posts in the forum debating, even arguing, that 1PD or 2PD is the most efficient way to drive. I have long taken the position that you can drive equally efficiently using either method, but I have never seen anyone prove it with real data. So that is what I set out to do.

First off, it is important to understand that in the MME, 1PD works exactly the same way either in Whisper, Engage or Unbridled (mine still has the “d”). So it does not matter, but all my testing was done using Whisper mode.

The main reason I use Whisper in my GT is the way Adaptive Cruise behaves: it is MUCH smoother if the car is in Whisper. And I use Adaptive Cruise a lot, like every time I drive. Switching back and forth from Unbridled to Whisper is too much of a PIA to make it worth it. I can still get 1000 Amps of acceleration just as easily in Whisper as I can in Unbridled, so I am not really missing anything.

To compare regeneration between 1PD and 2 PD I did two different tests.

  1. I measured the maximum regeneration I could achieve in each mode.I did this by driving as aggressively as possible, slowing as fast as 1PD could slow without using the brake pedal. In 2PD obviously I had to use the brake pedal to slow down.
  2. I did the exact same stop (same distance at the exactly same place in the road) from 50 mph using each mode. I tried very hard to slow down at the same rate in both 1PD and 2PD. That meant in 1PD I had to carefully modulate the go-pedal to slow down gradually to the stoplight while never pressing the brake pedal.

Results Summary

  1. 2PD generates a higher level of regeneration to the battery than 1 PD does. Of course if you drive using 1PD, you can also use the brakes, which allows you to increase the regeneration before the friction brakes engage. 1PD is not set to maximum regen, obviously.
  2. Both 1PD and 2PD appear to generate exactly the same amount of regeneration when stopping from the same speed and for the same distance.

Results Details - Test 1

The maximum regeneration I could get using 1PD was around 86 kW. The reason the chart below shows 94.76 kW is because I came up on some traffic and had to briefly use the brake pedal. Rather than redo the entire test, I just used it as is. But obviously it isn’t even close to what 2PD can produce. I am sure if I tested more, I could exceed 123.73 kW in 2PD as well. If I were to guess, maybe the limit is around 125 kW? Could it really be a nice round number like that?

vN1uEc1mLp2daaquf5ZDgwOW9CMlP6gIS2K8XEhh0YBYwBQFIU.png


Results Details - Test 2

The graphs really speak for themselves mostly. What is interesting is I was able to stop more smoothly using 1PD, as shown in the data. You can see I slowed down very gradually using 1PD, but had less of a smooth ramp in 2PD. People often think they can drive more smoothly using 2PD, but apparently, I can’t.

The regeneration graph shows I got a lot more initial regen in 2PD, but since I slowed more abruptly, I had to back off in order to reach the stoplight. But visually you can tell that the same amount of energy was returned to the battery.

_AaDvKaGcp2DK_UnUKBgD6W_6ZqUhB5Y2YpsmsCLfP1eqWrym0.png


Conclusion

Drive in any mode that makes you happy, but don’t pick a drive mode just because you think it is more efficient. Maybe it is easier for you to drive more efficiently in 1PD or 2PD, but it still comes down to the way you drive and not the drive mode. You can be just as efficient in 1PD as in 2PD. It is just a different way of driving.

Note: this conclusion only applies to the MME. Other car manufacturers may use brake blending differently in different modes, so I would not assume you can repeat this in every BEV. On the other hand, this is how every BEV should behave IMO. So if others do not, it is because they are inferior. Vastly inferior.

Now go out there and do some WOTs! This car is made for fun, not efficiency!
 

SpaceEVDriver

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Interesting. And not unexpected.

Was there a significant difference in battery temperature between the runs?
 
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mkhuffman

mkhuffman

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Interesting. And not unexpected.

Was there a significant difference in battery temperature between the runs?
Since I did the tests one right after the other, there should not have been any significant difference. But I didn't record battery temperature.
 

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That initial big spike in regen is why I don’t like 2PD on the MME. Ford has some poor programming that over amplifies the initial brake pedal response, so you always get that big spike seemingly whenever you touch the brake pedal. It’s much more difficult to drive the MME smoothly in 2PD because of all the brake jerks.

As you probably know, 1PD whisper doesn’t use all of the available regen, but unbridled tries to use the full 100+ kW (depends on speed).

All of the 1PD modes try to use regen exclusively to slow the car, so are more or less the same efficiency.

But I agree, 1PD is probably just slightly (immeasurably?) more efficient than 2PD just by virtue of it being smoother and more consistent. But virtually the same. How you drive is much more important than the drive mode you select.
 
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mkhuffman

mkhuffman

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As you probably know, 1PD whisperer doesn’t use all of the available regen, but unbridled tries to use the full 100+ kW (depends on speed).
I will need to edit my OP because I cannot feel the regen difference between Whisper and Unbridled in 1PD. Have you measured a difference? I will do some more testing myself to see if I can get 100 kW in 1PD. I could not get that in Whisper.
 


Mach-Lee

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I will need to edit my OP because I cannot feel the regen difference between Whisper and Unbridled in 1PD. Have you measured a difference? I will do some more testing myself to see if I can get 100 kW in 1PD. I could not get that in Whisper.
Yeah, do a 70-0 in the different modes by just lifting off in 1PD. Make sure battery is warmed up above 55F.
 

21st Century Pony

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Interesting data. Thank you.
 

HuntingPudel

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Pretty much what I have been saying all along. Thanks for taking the time to gather and post data. 😊🐩
 

jlauro

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All of the 1PD modes try to use regen exclusively to slow the car, so are more or less the same efficiency.

But I agree, 1PD is probably just slightly (immeasurably?) more efficient than 2PD just by virtue of it being smoother and more consistent. But virtually the same. How you drive is much more important than the drive mode you select.
It is largely your driving style and the mode. In 2PD mode, unbridled is not as smooth as whisper. On the plus side, unbridled is more aggressive of using regen when you take your foot off the brake and is more efficient then 1PD as it will not kick in the mechanical brakes (unlike 1PD) until you actually press the brake pedal. Anyways, the efficiencies between 1PD and 2PD are insignificant.
 

dbsb3233

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That initial big spike in regen is why I don’t like 2PD on the MME. Ford has some poor programming that over amplifies the initial brake pedal response, so you always get that big spike seemingly whenever you touch the brake pedal. It’s much more difficult to drive the MME smoothly in 2PD because of all the brake jerks.

As you probably know, 1PD whisper doesn’t use all of the available regen, but unbridled tries to use the full 100+ kW (depends on speed).

All of the 1PD modes try to use regen exclusively to slow the car, so are more or less the same efficiency.

But I agree, 1PD is probably just slightly (immeasurably?) more efficient than 2PD just by virtue of it being smoother and more consistent. But virtually the same. How you drive is much more important than the drive mode you select.
That's why I use 2PD Whisper + L gear 100% of the time. The regen from L does nearly all my slowing from high or medium speeds, and it's nicely moderated/smoothed with the go-pedal.

Then I apply the brake pedal for the final stopping, or if I need a bit more slowing than L regen offers (but L is usually enough). I get to keep creep and brake control in my garage and parking spots that way, which is where I hate 1PD.

Only part that's still annoying is the car's transition between regen and friction brakes, which is sometimes grabby down at like 3 MPH just before coming to a complete stop. They still haven't gotten that tuning right.
 
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HuntingPudel

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Didn't realize people were using 1PD to be more efficient, I just think it's a way more fun method to drive. Makes me feel like I've got a $60k golf cart.
LOL I hate golf carts. 🤣🐩
 

azerik

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which is sometimes grabby down at like 3 MPH just before coming to a complete stop. They still haven't gotten that tuning right.
Some of that (or a whole lot of that) could be rust on the rotors. My FFE after it'd rain is a nightmare. It'll regen down to just about 10 mph. Then it switches to the brakes and if rusted it's like getting rear ended with the brakes on, sometimes my face nearly hitting the steering wheel. A couple of 'spirited' stops to knock the rust off and we're back to normal.
It's interesting that Ford hasn't figured this blending out after over a decade of HEV/BEV's.
I have been looking into changing the front pads as the Job1's are FAR FAR to grabby no matter what I do. I guess some WD40 might help lol.:rolleyes:

BTW (side question for the 1pd'ers) After 4.1.2 is anyone else's 1pd randomly not regen'ing enough to stop without brake pedal aid? I've come way closer than I'd like to quite a few times thinking 1pd just kinda gave up doing the braking completely when rolling up to a light. I was under the impression that the front camera would see the car in front of me and stop more, or I don't know, stop completely. But I've had to jump on the brakes a lot more lately. (I'm not driving aggressively either, I lift WAY before I need to)
 

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That's why I use 2PD Whisper + L gear 100% of the time. The regen from L does nearly all my slowing from high or medium speeds, and it's nicely moderated/smoothed with the go-pedal.

Then I apply the brake pedal for the final stopping, or if I need a bit more slowing than L regen offers (but L is usually enough). I get to keep creep and brake control in my garage and parking spots that way, which is where I hate 1PD.

Only part that's still annoying is the car's transition between regen and friction brakes, which is sometimes grabby down at like 3 MPH just before coming to a complete stop. They still haven't gotten that tuning right.
Is there no issue with driving in L gear at any speed including highway driving? I was recently pondering how much difference there is between engaging 1DP vs. L in low sppeds as a curiosity, but thought at the very least L would have some side affect at higher rates of speed as it likely isn't "tuned" for that application.
 

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This is not surprising, the car was much more aggressively slowing down in 1PD when it first came out, then they pushed a software update that calmed down the braking when you lift off the pedal, so there is clearly some more regen to be able to grab if you hit the brake pedal before the friction brakes kick in.
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