# Regenerative Braking - Smart Fortwo



## brian_ (Feb 7, 2017)

SNClocks said:


> I recently managed to talk the local Porsche dealership into letting me test drive a Taycan. I was amazed - like zero regenerative braking - even with the braking turned on. I could not feel it at all. Dealer said it was to make it more like a normal Porsche. Never driven a normal Porsche - so I guess they don't have much decel. In comparison, my 2017 Smart Fortwo EV does a good job of slowing the car - though it could do more. Is it possible to increase the level of regenerative braking in a Smart Fortwo?


You may be confusing a lack of braking when the accelerator pedal is released with a lack of regenerative braking. An EV can be set up so that no braking happens until the driver actually pushes the brake pedal, but that braking can be all by regeneration, to the limit of the abilities of the motor, controller, and battery. The Taycan does most of its braking by regeneration, but it generally doesn't brake until the driver asks it to.

here's an article about Porsche's approach to regenerative braking control in the Taycan, and their reasons for it:
Why 2020 Porsche Taycan electric car won't have one-pedal driving
Notice that is says no "one-pedal driving", *not* no regeneration.

While my opinion doesn't matter, I like Porsche's approach much better than the one-pedal approach.

So, my guess is that you are looking for a more "one-pedal" approach for the Smart ForTwo, triggering more regenerative braking when the accelerator pedal is lifted. That's all controller programming, and I have no idea how you would change that.


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## SNClocks (Nov 2, 2019)

First and foremost - your opinion does matter. And thank you very much for the link.

It's funny - the sales guy, who had been to a 2 day "training" session on the cars, failed to mention the regenerative impact of using the brakes. Instead he focused on the availability of ceramic discs on the top model.

What was weird was driving the car. In regenerative mode - I could not feel decel when I let off the gas. It just coasted. The sales guy said several times that Porsche wanted it to feel like a normal Porsche - which didn't jibe.

Or, perhaps I am just too used to my old-fashioned gasoline-fueled cars that have way too big of engines and significant decel when I let off the gas.

At least now I understand their logic - for which I thank you. Now I need to talk a salesman out of a drive in a Leaf.

Again, thank you very much for taking the time to respond.


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## brian_ (Feb 7, 2017)

SNClocks said:


> It's funny - the sales guy, who had been to a 2 day "training" session on the cars, failed to mention the regenerative impact of using the brakes. Instead he focused on the availability of ceramic discs on the top model.


The sales guy is presumably working on commission, and so his only interest beyond getting you to buy a car is getting you to pay as much as possible for it. It has long annoyed me that Porsche prices for their base models are so high (for instance, a Macan starts at $10K more than an Audi Q5, although they are the same base vehicle), and yet to get one properly equipped you still need to pay tens of thousands of dollars for options. The base brakes on a Taycan are exotic (discs are coated with tungsten carbide, which they call Porsche Surface Coated Brakes), but they want to sell you ceramic discs (Porsche Ceramic Composite Brakes)... even though the friction brakes will almost never be used in normal driving.

A sales person only needs to understand what is available and how to sell it to you - they don't need to understand how anything works, although part of selling it to you is sounding like they understand anything you ask about.



SNClocks said:


> What was weird was driving the car. In regenerative mode - I could not feel decel when I let off the gas. It just coasted. The sales guy said several times that Porsche wanted it to feel like a normal Porsche - which didn't jibe.
> 
> Or, perhaps I am just too used to my old-fashioned gasoline-fueled cars that have way too big of engines and significant decel when I let off the gas.


That would have been the mode without regeneration on accelerator pedal release.

Engine braking depends on engine speed as well as displacement, and on what is done with the throttle when the pedal is released. In a traditional mechanical linkage the throttle is closed, maximizing engine braking, but with the electronic throttle control of this century it could do anything... I would prefer if it opened all the way (with fuel flow shut off) to coast as freely as possible, unless I shift down for engine braking. I've never driven a Porsche - let alone a new one - so I don't know how they act in this respect.



SNClocks said:


> Now I need to talk a salesman out of a drive in a Leaf.


If you can talk them into letting you drive a Taycan (which costs enough to buy a decent house in many places), a Leaf (and Bolt, and Kia, and anything else) should be no problem!


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## illanvoyager (Feb 25, 2020)

Steinbauer has a power module "chip tuner" that can increase available regen upon braking for 2013-2016 electric drive. no experience with it, and not sure if any other "chip tuners" or methods exist


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