Regenerative Braking?

[AHicks]

I’ve got about 550 miles on my Trek Verve+3 so far. We took them to Moab with us on vacation. I rode about 25 miles a couple days ago on a paved trail. It had a fairly steep climb and it was a back and forth trail. On the way down there was about a mile of long braking. The rest of the downhill part I was just coasting. So I’ve ridden 550 miles and 1 or 2 miles I would have used regenerative braking. I see why people say it just isn’t worth it.

Too many downs sides. The fact you have to have a direct drive shoots the whole plan down for me. If they ever come up with a direct drive capable of geared hub perfomance (without resorting to huge battery requirements/power), then they would have something worth talking about....

 

[fooferdoggie]

we could use it on our tandem. I am not brave anymore so only go down hills at 25 but sometimes its long. I have overheated the back brakes before. even with 203mm rotors 4 piston deore calipers with cooling fins. I get black gunk on the rear rotor.

 

[jodi2]

I’ve got about 550 miles on my Trek Verve+3 so far. We took them to Moab with us on vacation. I rode about 25 miles a couple days ago on a paved trail. It had a fairly steep climb and it was a back and forth trail. On the way down there was about a mile of long braking. The rest of the downhill part I was just coasting. So I’ve ridden 550 miles and 1 or 2 miles I would have used regenerative braking. I see why people say it just isn’t worth it.

You could say the same for an electric car if you only use higways, the recovered energy would be very little there. But on average quite a lot 'cause of the weight...

Too many downs sides. The fact you have to have a direct drive shoots the whole plan down for me. If they ever come up with a direct drive capable of geared hub perfomance (without resorting to huge battery requirements/power), then they would have something worth talking about....

As we found out in the posts before, there will never be much benefit from reg. braking in standard ebikes, also 'cause of weight...

we could use it on our tandem. I am not brave anymore so only go down hills at 25 but sometimes its long. I have overheated the back brakes before. even with 203mm rotors 4 piston deore calipers with cooling fins. I get black gunk on the rear rotor.

Tandem would also be an interesting use case apart from cargo ebikes. I remember our first journey on our tandem when we came down a terrible and totally unexpected hill (a detour due to constructions on a famous RIVER cycle tour for FAMILIES!) and had to slide totally helpless with overheated disc brakes with 15mph over a street with a stop sign (just by accident no car this moment). We were really frighteened and added back home also a rim brake to the front wheel. But much cooler would be a pedelec with regenerative braking and charging the battery!

 

[Stefan Mikes]

let me ask, was it somewhere here and you now repeat my phrases or do you get this arguments from somewhere else?

I read the explanation why regenerative braking had little sense for e-bikes long time ago. I mentioned you because you have owned a Stromer, and Stromer is one of few respected brands that use regenerative braking in their e-bikes. I wanted to hear your honest opinion, and thank you very much for it.

 

[Johnny]

I'm not completely sure why there is no/never reg. braking in geared (middle) ebike motors and only in a few hub motors.

Because there is a clutch at the rear wheel. For regen braking to work, when the wheel turns the motor always has to turn with it. However when you stop pedaling the wheel will keep on turning without turning the chain or the motor. There needs to be a significant design change to make regen work for mid drives.

Regen works and works very well. It is not just about recharging the battery which actually can give you %5-%10 depending on the hill, it also is a greatly reduces wear on the brakes. On my long descents it is much better than a regular brake for regulating the speed.

 

[jodi2]

Stefan, I see you understood me, even in my bad English... ;-)

I found a thread in our german pedelec (ebike) forum, where a well-known/very respected and technically experienced User talked about his "recovery rate" with his BionX ebikes. It confirms my personal experiences of very little gain for a speed ebike (class 3 or 45km/h) in flat regions. But he also says, he gains up to 50% of range with his slow ebikes on very hilly rides through the mountains. I first could not believe this, until I saw his note "with a LOT of leg power". Later he explained it more detailed, on very "sporty" tours in the mountains he needs only about 3Wh/km from his battery (what is very unusual for a heavy&powerful hub motor speed ebike which use 3-5 times more, it's more like assist drives like Specialized SL or Fazua). Downhill on these tours he can recover about 1Wh/km.
So he is completely ignoring the energy he himself adds, which is even more than the motor does.

And this reg. rate seems great, but on the downside he carries always at least a 10kg "pack" of big&heavy motor and battery with him. Which needs more battery and even worse, gives you a terrible feeling riding&handling the bike, all the time. And is less capable for strong&long uphills than a mid motor. If you don't need or use the power of the strong hub motor but only very little motor support, you go better with a a light assist drive like Specialized SL or Fazua I think...
I used my Stromer a few times for maybe maximum 10km in level 1, which on average is around 8Wh/km. It feels terrible, 3Wh/km would be a nightmare for me on such a heavy ebike and the resistance of the hub motor. It's possible and ok to reach your final destination (also riding without motor support), but it's no fun at all. It's like pushing your Ferrari...
With the Creo SL 3Wh/km is almost my usual average consumption. I guess it's almost not faster than with the Stromer but much more fun and satisfying.

But he is right, that the gain in range on a usual ebike/pedelec is much higher. It's wrong if we calculate only with the capacity of the battery like for an electric car. On an (fast ridden) speed ebike with hub motor capable of reg. braking on average maybe 1/3 of the power comes from the rider's legs. So 3% gained reg. energy brings maybe 4-5% more range.

 

[Johnny]

I used my Stromer a few times for maybe maximum 10km in level 1, which on average is around 8Wh/km. It feels terrible, 3Wh/km would be a nightmare for me on such a heavy ebike and the resistance of the hub motor.

Funny, I almost exclusively ride my Stromer at level 1, until last month I regularly climbed %20 grade sections for exercise at level 1(my consumption is around 11wh/mile depending on the speeds I keep). While it is not the true Stromer experience I still find it to be quite powerful at level 1 and enjoy leisure rides on it. I also dialed level two, closer to the preset tour , bit less, and at that level I am reaching 28-29 on flats which is more than I ever need. I don't use anything above.
A couple of weeks ago a friend came to visit. He is a very fit cyclist who only rides his all carbon custom bikes. I wanted to get his opinion. He tried Stromer at level 1 only and his comments were, "It is good, I only feel different when going over bumps because at those times it feels softer.". When I asked about power he simply said "It goes, this is a lot of power". He also thinks that even level 1 gives a significant boost. His family also has an ebike, creo,(because they can not keep up with him otherwise) so he actually has experience on that one too. A long time ago he tried my bosh mid drive and it was a negative experience to say the least.

At this stage I love my Stromer but I can also say that if I get a new bike for leisure I would probably get a regular carbon bike or something like SL or Creo. For really long and steep climbs I can still do the climb without any assistance on those bikes but on stromer it would be a pain.

 

[retiredNH]

But he is right, that the gain in range on a usual ebike/pedelec is much higher. It's wrong if we calculate only with the capacity of the battery like for an electric car. On an (fast ridden) speed ebike with hub motor capable of reg. braking on average maybe 1/3 of the power comes from the rider's legs. So 3% gained reg. energy brings maybe 4-5% more range.

So 3-5% more range? At what price? What compromises? Heck, I could just peddle a bit harder and gain just as much range, couldn't I?

 

[jodi2]

Yes, it's a nice feature if it works and good to spare brakes, but it's not worth going crazy for it on an ebike.

Johnny, I also know others who are satisfied with their Stromers at level 1 or even without motor support. Of course it is ridable and it's great that you can finish almost any (flat) ride even if the battery is empty. Also this a big advantage compared to any electric car... ;-)
Maybe I should add, I bought my Stromer (and another speed ebike before) to ride to work 2x22km each day for several years over the whole year. It replaced a complete car/saved us from buying&maintaining a second car. But for this usage it had to serve my as fast as possible and reliable. This usage is quite common in Germany/Europe for speed/45km/h ebikes as we have several very bad and stupid rules against this type of ebike. They are not very common (about 1% of all sold ebikes in Germany, all others limited to 25km/h), so they are mostly bought&used by people who really "need the speed" and accept the (national) disadvantages of this ebike type.
I was almost not riding any bicycle in my free time due to this "heavy work usage". Three years ago we settled and now 40km one way is to much (for me) to cycle twice every day (now maybe once a week, due to Corona maybe once every two weeks). I started to cycle much more in my free time, first with my Stromer as my only good bike. But I soon started to dislike it's heavy handling, riding time/every minute of rain less/to get somewhere earlier did not matter anymore and sportive use/to power out the body and riding through the nature/not on roads (where speed ebike usage is illegal here :-( ) became more important. There I like gravel bike with or without motor or MTB Hardtail much more.
I still love my Stromer and think it's one of the best speed ebikes on the market (much more than my 45km/h Bosch before), but it's not my one&only tool for everything. I also love my Creo for free time rides in the mountains, but with it's 25km/h motor limit it's almost useless for me to ride to work with about 180-190 height meters on 40km. It's ok/possible (like my Stromer at level 1...) but that's not what it's made for, with my normal gravel bike I need only one minute more with maybe 1km/h less average speed.

 

[Johnny]

@jodi2 We are on the same page for the most part.

Mountain biking is a different animal. On technical terrain, off road you need to manipulate the whole body of the bike, hopping on it etc. and that is where they shine.

I have a different opinion than yours on gravel bikes though. I have a gravel bike and even though I like how light it is, it is not even close to an mtb in any way. I am also not a fan of drop bars for country roads. Lately my opinion is that light, FS XC bikes are much more versatile than gravel bikes.

Btw your problem about rain is most likely because of the tires. Pirelli tires are amazing on dry pavement but really bad if it is raining heavily or you are on loose gravel( I even did a mild mtb climb with it, climbing was fine but on the way back I had to dismount and walk since it was impossible to brake without sliding).

 

[Stefan Mikes]

I have a different opinion than yours on gravel bikes though. I have a gravel bike and even though I like how light it is, it is not even close to an mtb in any way. I am also not a fan of drop bars for country roads. Lately my opinion is that light, FS XC bikes are much more versatile than gravel bikes.

Although I agree an XC bike is superior to a gravel bike in terms of traction, handling, and ride comfort in rough terrain, it is not the idea of gravel cycling, where:

• You ride in a group (and the sense of both camaraderie and competition is important there)
• You need to be very fast on-road and pretty fast off-road
• You're riding long distances, with 200 km being rather a norm than an exception
• You need to be able to carry your gravel bike in terrain that cannot be ridden. It is sometimes quite a big distance.

Gravel bikes have to be as lightweight as possible, which eliminates full-power e-bikes from the equation. I tried riding a derestricted FS e-MTB on a 90 km gravel group ride and failed (could not catch up with the group). I managed two (80 and 117 km) gravel group rides that were defined as "a leisure Sunday excursion"; I rode a non-suspension Vado 5.0, and made it. I could, however, notice that my Vado (despite of suspension handlebars and Kinekt 2.1) felt very shaky while my buddies rode their gravel bikes as if no bumps existed. I asked them the question why. Their answer was: "Your e-bike is very heavy, and thus susceptible to vibrations. It is not the case with our lightweight gravel bikes".

I didn't need an FS XC e-bike for gravel cycling. I would appreciate a gravel e-bike though.

Typical ride metrics for a gravel cyclist during this cold Autumn. The temperature for the guy's group ride was 45 F, hence a relatively short distance.

 

[jodi2]

After three years of graveI bike (with and without motor) I now own about a month an MTB XC hardtail. I also joined before some MTB tours and was able to "make it" somehow. But I clearly now see the differences/where each of these bikes has it's advantages and disadvantages due to my own experiences with each one. I also have several MTB experienced friends who ask me why I chose a hardtail and not a fully. A few weeks earlier I would have said "I don't need a fully, I can make almost everything with the hardtail ...". Now I respect other bike categories more and would say "I don't know yet and don't have enough experience with fullies. And you never know where your own journey goes...".

But we really have left the topic here I think. Speed ebike as these are almost the only ones with reg. braking, maybe still ok. But gravel and MTB biking?

 

[Johnny]

But we really have left the topic here I think. Speed ebike as these are almost the only ones with reg. braking, maybe still ok. But gravel and MTB biking?

Yeah, but you are the one who brought those subjects up first (mtb, gravel bike etc.).

 

[Rider51]

Not that everyone has $10k lying around, but I can all but assure you a bike like the S-Works Epic HT, with 2.0" race tires set to a fairly high pressure, and the fork locked out much of the time is going to perform extremely well on gravel. In fact, in recent years we've seen quite a few people race XC HT bikes in gravel fairly well, especially rough courses. Lots of videos on YT to support this. There's not a huge difference between the Epic HT, and the Diverge EVO. Mostly the fork, and tires.

An ebike? That's another issue. Only the Creo EVO (obviously) and a modified Vado SL (with preferably lighter wheels, and true gravel tires) is going to cross this threshold, at least in the Specialized line-up.

 

[jodi2]

Not that everyone has $10k lying around, but I can all but assure you a bike like the S-Works Epic HT, with 2.0" race tires set to a fairly high pressure, and the fork locked out much of the time is going to perform extremely well on gravel. In fact, in recent years we've seen quite a few people race XC HT bikes in gravel fairly well, especially rough courses. Lots of videos on YT to support this. There's not a huge difference between the Epic HT, and the Diverge EVO. Mostly the fork, and tires.

Well, if everyone want's to go on with this topic, I'm the last one to stop it... ;-)
As I have gravel bike(s) and a XC HT MTB very similar to the Epic HT (ok, about 1000g heavier and $8000 cheaper...) I disagree.
We have a local net of very nice MTB trips in our mountains, which you can download with GPS data and a short description. There are four categories: 1) very easy (also for families) 2) beginner 2) advanced 3) expert. Or in other word easy gravel, advanced gravel, hardtail, trailbike/fully with quite some experience.
Yesterday I did a 35km tour cat. 2 with 16km before to ride to the start and to afterwards back home. I felt very fine with the gravel bike. There where 3-4 sections a little bit challenging but never dangerous and when you started to worry, it was already over and flat again. The whole tour would have been ok with the XC HT as well. Riding back home I was cold, it was getting dark and I wanted to get home asap. Different then to get to thet starting point I took the direct way home only on roads and was almost flying with an average speed of 38km/h for the whole way and felt fine with the lower position and with my tires. Of course this part would have been possible with an XC HT as well, but far from feeling fine or from 38km/h average speed. On unpaved gravel paths with 25km/h they may be similar but not on pure tarmac. I do quite a lot of sections like this with the gravel bike "connecting" the unpaved/offroad sections, so gravel is a great combo for ME. For a 180km day trip only an tarmac the gravel bike surely does not "feel fine" anymore.
And back to MTBs: My cat. 2 tour yesterday with a fully would have been a little bit boring. A cat. 1 tour would be boring with the HT. A cat. 3 tour difficult with the gravel bike. A cat. 4 with the HT.
Every bike has it best use case and is only a compromise for cases to for from that. That's what I wanted to point out already yesterday.

 

[kmccune]

I’ve got about 550 miles on my Trek Verve+3 so far. We took them to Moab with us on vacation. I rode about 25 miles a couple days ago on a paved trail. It had a fairly steep climb and it was a back and forth trail. On the way down there was about a mile of long braking. The rest of the downhill part I was just coasting. So I’ve ridden 550 miles and 1 or 2 miles I would have used regenerative braking. I see why people say it just isn’t worth it.

For the purpose of extending range- not so much, saving and helping brakes a winner for sure, you can bet I will use it if available.

 

[kmccune]

Too many downs sides. The fact you have to have a direct drive shoots the whole plan down for me. If they ever come up with a direct drive capable of geared hub perfomance (without resorting to huge battery requirements/power), then they would have something worth talking about....

Justin can set you up with a geared hub motor with regen I do not have the link, but there is a video of what full regen can do-it was amazing. "One other thing", a powerful light can be installed to eat up the excess return if desired( Electromotives use a resistance bar)

 

[AHicks]

Justin can set you up with a geared hub motor with regen I do not have the link, but there is a video of what full regen can do-it was amazing. "One other thing", a powerful light can be installed to eat up the excess return if desired( Electromotives use a resistance bar)

Justin meaning Grin Technologies, right?
The only reason I don't have one of his kits already is the CA-3 display. It's right out of the 70's. I know it's super capable, but it's HUGE compared to other decent displays, and it offers only 2 lines of data. He's offering some of the latest technology/design available in the GMAC, that I would just love to have/mess with, with this absolute dinosaur display. Might work for some, but I'm not buying it. Not with that display.... -Al

 

[retiredNH]

Justin meaning Grin Technologies, right?
The only reason I don't have one of his kits already is the CA-3 display. It's right out of the 70's. I know it's super capable, but it's HUGE compared to other decent displays, and it offers only 2 lines of data. He's offering some of the latest technology/design available in the GMAC, that I would just love to have/mess with, with this absolute dinosaur display. Might work for some, but I'm not buying it. Not with that display.... -Al

Just looked at the CA3 display. It reminds me of the add on trip computer I bought about 15 years ago for a Honda Accord. Haven't seen that kind of dot matrix display in years.

 

[Rider51]

Well, if everyone want's to go on with this topic, I'm the last one to stop it... ;-)
As I have gravel bike(s) and a XC HT MTB very similar to the Epic HT (ok, about 1000g heavier and $8000 cheaper...) I disagree.
We have a local net of very nice MTB trips in our mountains, which you can download with GPS data and a short description. There are for categories: 1) very easy (also for families) 2) beginner 2) advanced 3) expert. Or in other word easy gravel, advanced gravel, hardtail, trailbike/fully with quite some experience.
Yesterday I did a 35km tour cat. 2 with 16km before to ride to the start and to afterwards back home. I felt very fine with the gravel bike. There where 3-4 sections a little bit challenging but never dangerous and when you started to worry, it was already over and flat again. The whole tour would have been ok with the XC HT as well. Riding back home I was cold, it was getting dark and I wanted to get home asap. Different then to get to thet starting point I took the direct way home only on roads and was almost flying with an average speed of 38km/h for the whole way and felt fine with the lower position and with my tires. Of course this part would have been possible with an XC HT as well, but far from feeling fine or from 38km/h average speed. On unpaved gravel paths with 25km/h they may be similar but not on pure tarmac. I do quite a lot of sections like this with the gravel bike "connecting" the unpaved/offroad sections, so gravel is a great combo for ME. For a 180km day trip only an tarmac the gravel bike surely does not "feel fine" anymore.
And back to MTBs: My cat. 2 tour yesterday with a fully would have been a little bit boring. A cat. 1 tour would be boring with the HT. A cat. 3 tour difficult with the gravel bike. A cat. 4 with the HT.
Every bike has it best use case and is only a compromise for cases to for from that. That's what I wanted to point out already yesterday.

You do bring up an excellent point. A lot of gravel events (races, or just rides) have decent sized distances on tarmac, or really hard packed fire road. Even a S-Works Epic HT with the configuration I said will underperform there. But if one does start watching gravel events, for whatever the reason, some are mostly on gravel, with very little tarmac, and even chunks of green/easy singletrack, with bits of grass, and such thrown in. That's where the high quality, lightweight XC HT bike will perform extremely well.

I supposed it depends on how one is micro-analyzing any ride, doesn't it! KM by KM, section by section!