Using the manual regenerative braking feature

Soquel

New Member
Hello everyone, I'm a relatively new ST2 rider and have really enjoyed my bike for the 3 months that I have owned it. Great machine.

I really only have one question.... I have a good 11 mile climb that is basically right out my driveway. I make the top with about 50% charge left using a customized setting. For the ride down, my hope is to utilize the manual regenerative braking turned way up to both manage my speed without braking as well as recharge my battery. I do manage to get a bit of a charge but not what I would expect on an 11 mile, 35-45 mile per hour descent. I turn the regen all the way up. Doesn't seem to curtail my speed as much as I would think. Still maintain 35mph easily. Also, when I hit a flat spot and start peddling my understanding is that it should switch off the manual setting but it doesn't unless I do it manually by depressing the controls. That works, but so should peddling right?

Anyhow next trip I will log the regeneration % carefully and let you all know.

Love the bike though, this is the only thing that has me confused.

Thanks!
 

David1

Active Member
I am pretty new to the St2 experience myself. Amazing bike, I wonder what Orville and Wilber would think? Please keep us posted on what you learn. I only discovered the Regen.button recently, I use it to save my brake pads. Ill check mine to see if applying the brakes or peddling stops regin. braking. Love mine! Be safe 35 is fast! . One question . Mine has severe head shake with hands off riding. In motorcycling its called a tank slapper. Any thing like this occurring with yours?
 

bluecat

Well-Known Member
... get a bit of a charge but not what I would expect on an 11 mile, 35-45 mile per hour descent. ...

The rules of physics are ruthless.

100% regeneration is impossible. The limiting factor is the amperage. The charging amperage is always lower than driving amperage. With this fact, time becomes crucial. Example: If you take 30' for climbing, then you should set the regen-rate at strength from that results at least the same duration for the descent. Unfortunately, this will lead to a ridiculous speed...
 

MLB

Well-Known Member
I dont' think my ST1 would roll 35mph down the side of a building on max regen. It slows me down significantly.
I am pretty new to the St2 experience myself. Amazing bike, I wonder what Orville and Wilber would think? Please keep us posted on what you learn. I only discovered the Regen.button recently, I use it to save my brake pads. Ill check mine to see if applying the brakes or peddling stops regin. braking. Love mine! Be safe 35 is fast! . One question . Mine has severe head shake with hands off riding. In motorcycling its called a tank slapper. Any thing like this occurring with yours?

Well there's head shake and then there's a tank slapper when the head shake is bad enough to bounce your balls off the gas tank. at that point you're usually crashing.
Can't be good (or normal!) though I wouldn't think to ride my 60lb bike with no hands.
 

Soquel

New Member
Understood on the regen %. I'm not expecting much of a recharge but will get more specific on what I am getting this week sometime. I would think it would slow me down more significantly. I am wondering if the regen cuts off with speed? Or a very steep descent perhaps.

I do ride handsoff, not at 35mph for sure but at about 20mph and it doesn't give me much head shake... more than my nice road bike but certainly tolerable.
 

David1

Active Member
Thats great yours doesn't start shaking. Ill check my head stock bearings , could be to loose. There is a little rubber plug over where I believe you get to the adjustment screw. Probably an Allen head .
 

David1

Active Member
I don't ride fast either hands off. just a moment to relax my back and hands upright. where I live is beginning to be bike friendly !! I'm able to explore more with the St2 to learn different routes, very nice , to bad more people don't know about these wonderful bikes.
 

Nebster

Member
You'll not get anywhere close to full regen on any electric vehicle.

First, the conversion efficiency in both directions is about 80% in the best systems. To make a full loop -- from energy stored in your battery, to motion, to putting the energy back in the battery, you need to square that number... 64%. In an ideal scenario you could theoretically get about that much back. (I doubt the Stromer drivetrain is even 80% efficient in both directions, but let's be generous.)

The second problem is external losses. Some (a lot) of the energy is lost to heating the air, the tire-road interface, and the other moving parts in your bike. At speeds like you're talking, you're probably spending half or more of the energy just moving air molecules around. So let's knock that back to 30% max.

The third problem is that the charge mechanism is non-linear; it has some fixed costs no matter the mechanical input/speed. The net result of this is that the BMS can't even charge the pack when you're below certain speeds, even if you asked for regen to slow you all the way to zero. So that energy is lost as well.

I would be surprised if a small system like a 500w ebike could achieve more than about 10% true round-trip regen except maybe on an ice rink on the moon. I think my ST1 gets closer to 1%, but it might be 2 or 3%... so little, unfortunately, that it's hardly worth fooling with except just to have a little break from full braking on the steeps.
 

bluecat

Well-Known Member
In terms of regeneration, there are worlds between St1 and ST2.

The efficiency depends on the rpm of the motor; luckily, there is no drivetrain in between, as the motor sits on the rear hub. From my experience, the motor brake is active close to the bike stand still. If you set it to max. before a steep descent, it could remain very low speed. But at the upper end of speed, the BMS will cut the regeneration. This is to protect the battery from overheating.

(With this, your Stromer will not have the same destiny as Mr. Piccard at Hawaii. ;-)
 

Nebster

Member
Unfortunately, even a 10x improvement on ST1 won't come close to providing what OP was hoping for (and what the marketing likes to suggest). I would love to see some rough numbers from anyone who's tried a serious climb and regen, but I'm betting it'll come in at a 10% total return (or less).
 

Rick Huizinga

Active Member
Mine has severe head shake with hands off riding.

Can you explain this behavior? I may have the same thing, where if I take my hands off the handlebars, they begin to vibrate rather intensely back-and-forth. In my case, the front tire is not uniform with some bulging that can be visibly seen when rotating the wheel on a stand.
 

David1

Active Member
motorcycles have a special attachment a rod that slides in and out that alleviates this behavior I'm waiting on a thud buster right now and I will speak with some shops about this issue and get back with more input about this issue.
 
D

Deleted member 803

Guest
Hello everyone, I'm a relatively new ST2 rider and have really enjoyed my bike for the 3 months that I have owned it. Great machine.

I really only have one question.... I have a good 11 mile climb that is basically right out my driveway. I make the top with about 50% charge left using a customized setting. For the ride down, my hope is to utilize the manual regenerative braking turned way up to both manage my speed without braking as well as recharge my battery. I do manage to get a bit of a charge but not what I would expect on an 11 mile, 35-45 mile per hour descent. I turn the regen all the way up. Doesn't seem to curtail my speed as much as I would think. Still maintain 35mph easily. Also, when I hit a flat spot and start peddling my understanding is that it should switch off the manual setting but it doesn't unless I do it manually by depressing the controls. That works, but so should peddling right?

Anyhow next trip I will log the regeneration % carefully and let you all know.

Love the bike though, this is the only thing that has me confused.

Thanks!
Are you the guy I saw at Peet's the other day with a great big grin on his face....................Careful, there may be a new ST2 owner jamming up Old San Jose with you.............LOL

So glad you are enjoying your new bike. I ride (or used to until today) my Neo Carbon around the the city every morning and wind up at Peet's. If I buy an St2 I'll let you know and perhaps we can do a ride together.
 
D

Deleted member 803

Guest
Headshake is common in motorcycling and the reason why manufacturers use steering dampers to remove the natural occurring oscillation that happens when a front wheel is at significant speed and there are imperfections in the road. Not sure how this is resolved on a bicycle. The steering dampers used on motorcycles have a variable effect. In other words they do almost nothing at slower speeds to inhibit the steering assembly shake but gradually slow the back and forth movement as the violence of the back and forth movement increases. I'm wondering if professional cyclists experience this when riding at 50-60km?
 

Soquel

New Member
Are you the guy I saw at Peet's the other day with a great big grin on his face....................Careful, there may be a new ST2 owner jamming up Old San Jose with you.............LOL

So glad you are enjoying your new bike. I ride (or used to until today) my Neo Carbon around the the city every morning and wind up at Peet's. If I buy an St2 I'll let you know and perhaps we can do a ride together.
That is me! Hope you are doing well. Took your advice and looked up the forum. Very cool.

The Old San Jose is a good ride for sure. One thing I learned the hard way is that with the agility setting turned up the bike can be a bit squirrely on a gravel road! No damage to the bike but definitely gave myself a nice big case of road rash! Peddle just a bit hard and the back end will come right around on you : )

Hopefully I'll see you around Peet's again sometime soon.
 

John ware

Active Member
Gentlemen, are you talking Old San Jose as in Santa Cruz/Soquel? If so perhaps we should have a meetup and ride to compare notes.
 
D

Deleted member 803

Guest
Gentlemen, are you talking Old San Jose as in Santa Cruz/Soquel? If so perhaps we should have a meetup and ride to compare notes.
John: Would love to. I am at Peet's Capitola just about everyday between 7:30 and 8am. However, there was a deep deep loss in my family that occurred yesterday so my schedule is a bit off. Spent last night in the garage mourning the loss of my Neo Carbon (sold yesterday). I am vacillating between the new Turbo SC and the ST2. I went to a dealer today over the hill for sizing on the ST2. The 17" feels much more comfortable over the top bar but the reach to the handlebar feels too short. The 20" bike gives no more than an inch of clearance over the top bar but the reach feels much better. Since I spend so little time straddling the top bar, I will probably go for the large size.

I'll decide tomorrow. The Stromer has a much more comfortable ride than the Turbo S. Specialized has added a 500W GoSwiss rear drive, a 690W battery, and has integrated BT and ant+ for controller fine tuning and the use of ant+ supported devices such as a heart rate chest strap. The 2016 ST2 will offer a DI2 electronic shifter, an almost 1KW battery, and comes with a handy dandy payment plan of $756/month for 36 months....what a deal!!!!!
 

John ware

Active Member
Wait, did you say 36 easy monthly payments of $756 ?!? The calculator says that works out to $27.2k. Yikes either interest rates are sky high, there was a typo or the 2016 is truly position to sell along side that gold AppleWatch and a slightly used Tesla.
 

Soquel

New Member
Gentlemen, are you talking Old San Jose as in Santa Cruz/Soquel? If so perhaps we should have a meetup and ride to compare notes.
Hi John,

Yep, Old San Jose road. I'm currently out of the country but when I get home let's see if we can set up a ride with 86! I saw another post of yours that looks like either Grey Whale ranch or Wilder ranch. I find that the stock tires are a bit to slick for my taste on gravel.
 
D

Deleted member 803

Guest
Wait, did you say 36 easy monthly payments of $756 ?!? The calculator says that works out to $27.2k. Yikes either interest rates are sky high, there was a typo or the 2016 is truly position to sell along side that gold AppleWatch and a slightly used Tesla.
Well you tell me. A DI2 has got to cost another 2-3K and the larger battery is more expensive. Wouldn't be surprised to find the 2016 premium model close to $10K. Perhaps some of their development costs have been amortized and they can begin to drop pricing. We shall see soon.