Do you know something about regenerative braking?

[jazzenator]

I appreciate your findings and the fact that you take the effort of sharing them. I don't claim to have the definitive answer. But there have been many discussions, on this forum, but also on the Dutch PHEV forum with > 3000 members, about the effect of selecting different B levels. Many of the discussions seem to lead to a conclusion that the B-level above all changes how the car responds to pressing / lifting the gas and break pedals (for instance , the gas pedal is remapped when you change the B-level). But not so much how the car itself behaves.

Ah OK! Many thanks for that. So it means that this is most likely a misperception on my part rather than the car regen braking more or less depending on the B level. Just so that I am clear in my mind. Thanks.

 

[kentphev]

Try this test... In B0 start braking then without changing pressure on the pedal flick up to B5. You will feel the regen effect ramp up massively.

Then see if you can get the same level of regen using just the brake in say B0 or B1. I've come to the conclusion that stamping hard on the brake in B0 is not the same as light braking in B5.

So brake+B5 will harvest more than just using the brake in B0, B1 etc. that's to say the level of regen seems to go up with brake use the same as it does in lift-and-coast.

 

[welljock]

Try this test... In B0 start braking then without changing pressure on the pedal flick up to B5. You will feel the regen effect ramp up massively.

Then see if you can get the same level of regen using just the brake in say B0 or B1. I've come to the conclusion that stamping hard on the brake in B0 is not the same as light braking in B5.

So brake+B5 will harvest more than just using the brake in B0, B1 etc. that's to say the level of regen seems to go up with brake use the same as it does in lift-and-coast.

Coincidentally I did that this morning and never noticed any difference in either the breaking or on the dial.

 

[Grigou]

Agree with you kentphev (and made the test many times in 8 months) : there is a huge difference in braking capacity between B0 and B5.
For me it is obvious.

But ... same discussion in a french forum, and I wonder if some cars may have different behaviour :?:

For information I have an Intense model (= without ACC).

 

[anko]

After this mornings run to the office, I start having doubts myself . So glad I wrote:

I don't claim to have the definitive answer..

 

[Grigou]

I have the definitive answer for MY car ...

 

[anko]

Well, I am still confused. Did my first two test while monitoring current going in and out of my battery.

Hitting the breaks in B5: 92 A (* 324 v = 29.8 kW)
Hitting the breaks n B0: around 90 A +/- a few.

These were not optimal, but similar conditions. Approaching a roundabout with about 40 - 50 MPH and braking late.

First test, my son was sitting next to me and het said it was at 92 A steady (3 - 4 frames per second).
Second test, I was by myself, so this was a bit less 'conclusive'.

It is just beautiful, what you can see with proper tools. During this trip, I drove 42,8 km on secondary roads, where my battery charge dropped form 34.30 Ah to 15.50 Ah (at that time, I had 12 km EV range left). I could actually 'witness' power consumption from the battery cooling device

 

[Grigou]

The problem is that the regenerative braking can reach, if I remember well, about 60 kW isn't it ? At least in good conditions of course : downhill or high speed. Downhill + highspeed is ideal.

And the question : is it possible to reach 60 kW in B0 ? I don't think so, but didn't measured anything : just feeling

 

[anko]

Indeed. Had to pick up my kid where I dropped him off earlier tonight. On the way back, we scored 155 amps (roughly 50 kW). Speeding up to about 100 km/h and slamming the break. So, the 92 amps I reported earlier was limited, either because I was not driving fast enough or because my battery was to full, to allow for max regen current. Stupid enough I forgot to retry in B0.

 

[duplo]

Try this test... In B0 start braking then without changing pressure on the pedal flick up to B5. You will feel the regen effect ramp up massively.

Then see if you can get the same level of regen using just the brake in say B0 or B1. I've come to the conclusion that stamping hard on the brake in B0 is not the same as light braking in B5.

So brake+B5 will harvest more than just using the brake in B0, B1 etc. that's to say the level of regen seems to go up with brake use the same as it does in lift-and-coast.

Also, if you watch the charge indicator when slowing in b5 and then you brake on top of that, the charge noticeably increases.

 

[anko]

Yes, it does. It increases from a certain value to a larger value. It tells us that B5 does not (always) max out regen breaking capacity. As a matter of fact, B5 breaking is programmed to establish a deceleration of 1 m/s2, regardless of your driving speed, vehicle weight and whether you are driving down or up hill (got this info from Mitsubishi, backed up with computer print outs and all). It will not maintain 1 m/s2 deceleration when the battery is near full (we are all aware of that) or when this requires more stopping power than the e-motors can provide (driving very fast or downhill). So, how much regen power you get by just letting go of the throttle in B5 depends on many factors.

How much regen power you get when flooring the break pedal IMHO depends on two factors:
- regen capacity of the e-motors
- bartery SOC (the lower the SOC, the more current the battery is willing to accept)

In B0, it does mostly the same. The difference for the first part of the above is that the target deceleration will be (far) less than 1.0 m/s2. I would like to think that it is 20% of 1.0 m/s2, but I have no reason for it, other than that it would make sense. For the second part, subject to this discussion is: is there a third parameter that controls how much regen power you get when slamming the breaks, namely the B setting? Using my scanner, I should be able to find out soon enough.

 

[Grigou]

For the second part, subject to this discussion is: is there a third parameter that controls how much regen power you get when slamming the breaks, namely the B setting? Using my scanner, I should be able to find out soon enough.

I will be very interested by the result

 

[anko]

Here it comes (almost). This morning I picked up the caravan at the dealer to bring it home. Normally a 7 km trip over secondary roads. I added some 55 km of motorway, to do some testing.

Indeed regen power is very much depending on SOC. No surprise there.

On the exit ramp, hitting the breaks firmly at about 80 km/h, I managed to get 155 Amps in B5, about 50 kW. During the trip, I thought the highest number we had seen in B0 was less than 100 Amps, but my son later said he saw 114 at one point. Either way, must be at least 25% - 35% less than B5.

This is in the extremes. How it is in medium situations (slowing down, instead of breaking hard) will be pretty difficult to observe, I am afraid.

 

[PeterGalbavy]

Got my first "no regen" surprise yesterday when I drove away from home just after charging. What a different car. Luckily, thanks to posts like this one, I was only surpised and not shocked