Regenerative Braking and RWD...

[KevinRS]

One reason not to put more weight to the rear in the design is that it is a truck. Most of the load that isn't the driver, front seat passenger, or in the frunk is going to be pretty much fully on the rear axles. Go to the big box store and get a dozen bags of concrete, that's 1200 lbs on the rear axle. That and the driver is going to be near the estimated spec for max load, but the truck has to be designed to not bottom out the rear with that load.

 

[cadblu]

Regen isn't for hard/immediate braking. Think of it as being more like "engine braking", where your car slows itself down when you aren't accelerating, especially when you shift into a lower gear. I think the Slate's rear wheels will have plenty of grip for that.

To all:
Just a word of caution regarding regen braking and OPD (one pedal driving) as per the situation highlighted in bold above.

You should be aware that in most cases where the vehicle is slowing down…

…your rear brake lights will go “on”… even though your foot never touches the brake pedal! The vehicle’s accelerometers sense it’s slowing down, so brake lamps go on, and you can’t prevent it.

You may ask, why do I bring this up?

Because if you have another vehicle following closely behind you, they will think you’re ‘brake checking.’ This will agitate tailgaters, or aggressive drivers in general, and can lead to road rage incidents.

Sorry, but I just needed to bring this up. I would say most EV owners are aware of, but it’s worth repeating.

 

[beatle]

Typically the brake lamps only go on when a certain amount of deceleration is detected - usually in line with what light use of friction brakes provide. Better this than brake lights that don't go on until you're basically stopped, as was the case with some Hyundai/Kia/Genesis models. That has since been fixed and brakes come on with less deceleration than before.

 

[metroshot]

Considering that some 80% of braking power comes from the front wheels and Slate is RWD, I can only assume that the regenerative braking capability will be rather minimal when compared to this. capability for AWD or FWD vehicles. Also, because of this, single pedal steering is unlikely. Is my understanding correct?

No, my BEV is RWD and regen occurs no matter how much coasting and braking I do.

This is what makes me upset with Slate - 1PD only which is harsh and not conducive to urban driving.

My BEV has a choice between 3 different regen harshness and 2 levels of 1PD or 2PD.

I drive mine in 2PD w/ mid level harshness.

Regen is super important to regain energy in downhills, braking and coasting.

 

[AZFox]

This is what makes me upset with Slate - 1PD only which is harsh and not conducive to urban driving.

An urban runabout pickup that isn't conducive to urban driving wouldn't make sense.

Could it be possible that there's a way to implement 1PD so it's conducive to urban driving?

The reason it seems possible to me is because removing my foot from the accelerator pedal of my golf cart doesn't cause any lurch. Regen deceleration continues and braking just adds to it.

 

[beatle]

I've never had a problem using 1PD smoothly. If you want less regen, just don't let off as much. 1PD excels in urban environments and stop and go traffic where you would otherwise be jockeying two pedals. In an EV I only use the brake pedal for emergency stops.

 

[metroshot]

An urban runabout pickup that isn't conducive to urban driving wouldn't make sense.

Could it be possible that there's a way to implement 1PD so it's conducive to urban driving?

The reason it seems possible to me is because removing my foot from the accelerator pedal of my golf cart doesn't cause any lurch. Regen deceleration continues and braking just adds to it.

Have you test driven a Tesla ?

When you jump off the throttle and onto the brakes because of drivers cutting you off, then you will feel the lurch and the repetition will make you nauseous.

 

[metroshot]

I've never had a problem using 1PD smoothly. If you want less regen, just don't let off as much. 1PD excels in urban environments and stop and go traffic where you would otherwise be jockeying two pedals. In an EV I only use the brake pedal for emergency stops.

Try driving in So Calif congested traffic - streets or freeways - every drive with idiot lane jumpers requires you to jump on the brakes since the regen is not enough to stop the car.

I know, my Tesla co workers have to do this and I end up getting nauseated.

 

[GaRailroader]

Try driving in So Calif congested traffic - streets or freeways - every drive with idiot lane jumpers requires you to jump on the brakes since the regen is not enough to stop the car.

I know, my Tesla co workers have to do this and I end up getting nauseated.

If you have to take your foot off the gas and jump on the brake isn’t it very similar to an ICE vehicle in that situation? Been driving EVs for 8 years and have no complaints on 1 PD driving. Like Beatle stated, if the regen is too aggressive then modulate the throttle longer. I think the learning curve with 1 pedal driving is taking your foot off the accelerator prematurely. Let off the accelerator and modulate the slow down rate with the throttle then take your foot completely off the throttle when you are ready to come to a complete stop.

 

[KevinRS]

It sounds like the Tesla issue being described here isn't a 1PD setting issue, but the Tesla's brakes grabbing too aggressively, or the driver having a heavy foot when they do switch to the brake. Maybe the brake pedal has little resistance.

 

[Tom Sawyer]

Have you test driven a Tesla ?

When you jump off the throttle and onto the brakes because of drivers cutting you off, then you will feel the lurch and the repetition will make you nauseous.

Try driving in So Calif congested traffic - streets or freeways - every drive with idiot lane jumpers requires you to jump on the brakes since the regen is not enough to stop the car.

I know, my Tesla co workers have to do this and I end up getting nauseated.

I've been driving a Tesla Model 3 for almost 4 years and have not experienced this nauseating braking feature.

 

[beatle]

Try driving in So Calif congested traffic - streets or freeways - every drive with idiot lane jumpers requires you to jump on the brakes since the regen is not enough to stop the car.

I know, my Tesla co workers have to do this and I end up getting nauseated.

I don't understand, you first said regen is "too harsh" so you dial it back to medium, and then you say it's not strong enough so you have to use the brakes. Which is it? I don't like having to use the brakes any more than the next guy who just got cut off. If that happens enough, you'll be nauseated no matter whether the car is using regen or friction brakes to slow down. But I will always take more regen. It's really only a bad thing if you can't modulate it. I am actually curious to try the Ioniq 5N track braking which goes up to 0.6g. That's more than double what I get out of the R1T which is already the strongest regen I've experienced.

 

[metroshot]

I don't understand, you first said regen is "too harsh" so you dial it back to medium, and then you say it's not strong enough so you have to use the brakes. Which is it? I don't like having to use the brakes any more than the next guy who just got cut off. If that happens enough, you'll be nauseated no matter whether the car is using regen or friction brakes to slow down. But I will always take more regen. It's really only a bad thing if you can't modulate it. I am actually curious to try the Ioniq 5N track braking which goes up to 0.6g. That's more than double what I get out of the R1T which is already the strongest regen I've experienced.

Ford EVs have both 1PD and 2PD choices. Both choices give you another level of regen/performance using the drive modes (Whisper, Engaged, Unbridled).

Total of 6 different drive modes depending on what the driver selects.

1PD in Unbridled mode has the most harsh regen but best performance (acceleration).

2PD in Whisper mode is the least regen but has ICE coasting feel when you pull your foot off the accelerator.

I drive 2PD in Engaged mode for moderate regen, but lots of coasting if I take my foot off the accelerator.

Tesla feels more like a 1PD in unbridled mode.
It's very harsh and unforgiving if you jump off the accelerator and jump onto the brakes as it's common here in So Calif driving.
Tesla no longer allows adjusting regen (current software) and is downright harsh.

 

[beatle]

I always drive our Mach-E in unbridled mode. If it feels "harsh and unforgiving" when transitioning from full regen to brakes, you probably either didn't actually need to use the brakes at all, or it's just an unavoidable panic stop that would be abrupt regardless of regen or brake use.

Also, California doesn't have a lock on bad drivers. They are everywhere.

As this all relates to Slate and this topic, it's probably moot as the regen will likely be a lot weaker than a car with 2+ motors anyway, given that it only has a rear motor and 50/50 weight distribution.

 

[ElectricShitbox]

I don't remember where I saw this, but I was under the impression that the Slate wasn't going to get full 1 pedal driving that blends in the friction brakes. So it would regen when you let off the throttle, and creep in drive. Not sure if pressing the brake pedal blends in regen with the friction brakes, but skipping that is the cheapest method, and the most like driving an automatic ICE vehicle.