Trail Cruiser
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It would be great if there are demo GMAC ebikes, especially at the hilly areas, So would be buyers will be able to compare different ebikes back to back.
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That's exactly consistent with what Bill Cummings said in the video. 1.5 miles on a battery that got about 30 miles. 5%. I've spoken with Bill on occasion over the past 4 years, and he strikes me as an extremely intelligent guy (but doesn't wear it on his sleeve and is VERY humble), and he is very experienced with ebikes, ebike design, working with motor manufacturers, and battery manufacturers, and awesome at trouble-shooting. Bill's general message was it wasn't practical, given that many people probably dont stop nearly enough in a typical ride, or necessarily get enough downhill momentum often enough, that adds up to a sufficient amount of kinetic energy that can be converted back to electrical, and that to do it right on an ebike involves a bit more than a simple 'switch.' The motor has to be designed for it.
Back to Ravi's message briefly here, for example, how much of the cost of the Stromer ST2, which today costs around $6500 at REI, has to do with Regen capability ? (rhetorical - dont answer - I dont wanna know and dont care) The extra 1.5 miles, probably could be much more easily gained and with fewer dollars, by simply getting even .5 amphour larger battery. Also, It costs less than 8 cents to recharge a 14 ah battery at 48 volts, so how much is the value of that 1.5 miles in every 30 ?
And I don't know how many people have the budget for a $6500 ebike, but in large part it appears Bill is addressing a general audience, where a large percentage of would be ebike buyers are more likely to be looking at a $1500 to maybe $3500 ebike, and they sometimes come up and ask dealers, or maybe they call Evelo , and they are curious about what they have heard about Re-gen, and whether it can be had on an ebike, and whether its really valuable or important. Is adding 1.5 miles to a battery that can provide 30 miles of range important ? And then these same customers ask, 'can I get that', or they might ask, "is it worth it to have on an ebike." (These are actual questions I have gotten - so again its nice to see a video like this)
So Generally speaking, to gain 1.5 miles on a $1500 to $3500 ebike, I would have to agree with Bill, that no its probably not really 'practical.' (for either the OEM's producing that type of ebike, or for the average customer, who probably doesnt want to spend or have the means to spend $6500 to get it. For someone who is buying a Stromer, and has the budget of $6500, which is very likely a very small part of the buying population, and who is likely buying the Stromer for a lot of other more important reasons, its probably a 'nice to have' little feature on it. Is it 'practical' on an ebike like that at that price ? Maybe. Especially given how pricey Stromer's batteries are, both in total cost, and on a watt-hour basis. How much could they take the price of the bike down if they didn't have Regen ? (I dont know - again rhetorical)
If you really want to get super technical, and theoretical, certainly 'regen' can add something. And judging from all the posts here, that is subject to debate on their definition of 'practical.' However, it does seem to me though, that a decent number of the posters debating the topic in this thread, are a lot more technical in general (Ravi's working on his Masters in engineering and batteries?) , and several of you on this thread getting a bit 'heated' certainly are way more technical than most of the AVERAGE customers I see everyday. It's those average 'joe or jane' customers that are the very likely audience Evelo sees everyday as well, and talks to on a daily basis, and as well as what most ebike dealers or bike shops will talk to everyday.
Anyway, I simply posted the video, because again, a) I get asked the question a lot more frequently than I would have ever expected b) there really hasn't been anything decent posted from any other ebike OEM even broaching the topic, and c) I'm a degreed mechanical engineer with quite a bit of practical motor experience, industrial equipment experience, and more than 34 years of being out there working with many energy technologies where the questions are a lot more challenging than this, but since my roles have been customer facing for most of those 34 years, I always truly appreciate when someone as smart as Bill, takes the time to explain something in laymans terms that can be very technical and hard for people to understand that dont have the same engineering or requisite technical background. Something like this video that takes the confusion out of it for a customer who may have run across the concept, or understands it from their experience with hybrid vehicles, and thinks it might be a cool thing to have, is probably being done as a result of them getting enough questions on it. Which is what Evelo's video series is all about. Providing some education that may not be out there for general consumption. I happen to like people and vendors who take the time to do these educational videos or articles. I believe those vendors do sincerely care about their customers.
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tomjasz
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Seems we have the experience to draw on with no attempt to sell. Unlike dealers posting here. Perhaps there are fellas that have more experience. Certainly there are many that know more than me. But you completely miss the point from the original post. It’s about BRAKING, not energy recovery. Being a dealer doesn’t make one an expert. Near as I can tell there are several posters here with more experience than you exhibit. It’s best to remain curious and not bite the hands of those you could learn from.
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AHicks
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If this is about regen's ability to put power back into a battery, I'll admit to anyone, any time, I'm not a fan. I would not be interested in regen for that reason only.
If this is about regen's ability to brake. That IS an attribute, and anybody saying otherwise, including dealers or a manf's, is supplying inaccurate or incomplete info. It's no different than saying engine braking on a vehicle isn't practical (see how far you get with that concept). The regen question may be better handled by asking about the bike rider's need for regen. Whether or not they can use it. This is no different than asking qualifying questions about the hundred other things that should be known prior to recommending a bike - unless you're simply trying to sell a bike out of inventory.
I don't blame a flat lander for considering regen frivolous (in it's present form) . Regen at this point is about long hills, the kind that can have you running 35mph if unchecked. Until something like the GMAC with it's MUCH more effective regen braking, has been out for a while anyway. That's going to be a game changer, even for a flat lander.
If this is about regen's ability to brake. That IS an attribute, and anybody saying otherwise, including dealers or a manf's, is supplying inaccurate or incomplete info. It's no different than saying engine braking on a vehicle isn't practical (see how far you get with that concept). The regen question may be better handled by asking about the bike rider's need for regen. Whether or not they can use it. This is no different than asking qualifying questions about the hundred other things that should be known prior to recommending a bike - unless you're simply trying to sell a bike out of inventory.
I don't blame a flat lander for considering regen frivolous (in it's present form) . Regen at this point is about long hills, the kind that can have you running 35mph if unchecked. Until something like the GMAC with it's MUCH more effective regen braking, has been out for a while anyway. That's going to be a game changer, even for a flat lander.
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Trail Cruiser
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Direct drives are associated with regen braking and then PRICE. It is partially true, Stromer is a premium brand thus it also has a premium price tag. The other factor is the use of more rare earth magnets (adds to the raw cost) and also is not environmentally attractive since rare earth magnet materials are mined. With more magnets also results to increased weight (but not much).
However, that negative association are all gone with the GMAC since it does not need excess magnets and GMAC is not a proprietary ebike motor. And it has stronger regen stopping power.
However, that negative association are all gone with the GMAC since it does not need excess magnets and GMAC is not a proprietary ebike motor. And it has stronger regen stopping power.
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AHicks
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A half mile or less of down hill run is plenty of time to build up a head of steam that will be dangerous or unnerving if left unchecked.
And by design, regen does turn a DD hub motor into a regen brake!
Last, the amount of electricity consumed by a DD while coasting is small enough to be considered inconsequential. The watt meter drops to 0, with no noticeable slowing of the bike. In theory, the clutched gear drive consumes less, agreed, but from a practical standpoint, this is a non event.
And by design, regen does turn a DD hub motor into a regen brake!
Last, the amount of electricity consumed by a DD while coasting is small enough to be considered inconsequential. The watt meter drops to 0, with no noticeable slowing of the bike. In theory, the clutched gear drive consumes less, agreed, but from a practical standpoint, this is a non event.
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It is my understanding that regen on DD hubs and clutch-less gear hubs like the GMAC having regen function added to a controller is a few $s. Maybe someone that designs controllers can actually chime in on this because I believe a lot of the negativity about regen is being put out by advocates of mid drives that can't do it.
Without a doubt that when going down a long hill when you don't want to go too fast not having to ride your brakes all the way down is a big deal - both for safety and for reduced brake wear. Let's get real riders!! The 5-10% recovery of energy isn't the primary benefit of regen but it's not insignificant either.
Again.... adding regen to a controller adds only a few $s. I'm sure less the cost of 1 set of brake pads and the service cost/time to install them. Are mid-drive manufacturers paying you to make false claims about the benefits of regen??? Be objective on EBR so people can make informed decisions!!!
tomjasz
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Only those that remain clueless and use predatory sales techniques. I support mid drives but don't ever push them on people. I'm just wrapping up a gratis project for a young couple converting their kid hauler. ZERO profit, just couldn't sell them something they don't need. It was about a 4-hour project including finding replacement parts from Italy. Overall I find mids ARE oversold. One size never fits all.
Only the cheapest China controllers lack regen. Anyone adding more than a couple of dollars is also predatory.
There is no difference between a DD hub that is on a bike with regen and one without - the capability is in the controller or not. Geared hub motor manufacturers decide for the most part that the ability to free wheel was more important than regen so the bikes were easy to ride if battery power was ever lost (riding a DD hub without a battery is like riding up a slight hill constantly). Grin added a cool feature on the Phaserunner that automatically drops the assist power to barely overcome the cogging of the motor when the battery gets to a level that I believe is user definable. The feel that with the clutch-less regen capability this mode can be used for a very long range before the battery ever goes entirely dead and then you are left with the cogging of a typical DD hub.
DD hubs are heavy mainly because the steel backing plates to complete the magnetic poles/circuit tend to be very thick. Grin has DD hub that solves that problem too. Someone should put their All-Axle hub motor in a rear wheel on an OEM bike but that is unlikely with the business failures of BionX and GoSwiss (these companies did not market well against the mid-drives). How many riders even comprehend the advantages and disadvantages of the various motor technologies - everyone is too busy trying to keep up the Kardashians to learn anything technical. We are just a dumbing down society...that's just a fact. If you've ever tried to sell something that requires some education of the public it really resonates as a hard truth.
DD hubs are heavy mainly because the steel backing plates to complete the magnetic poles/circuit tend to be very thick. Grin has DD hub that solves that problem too. Someone should put their All-Axle hub motor in a rear wheel on an OEM bike but that is unlikely with the business failures of BionX and GoSwiss (these companies did not market well against the mid-drives). How many riders even comprehend the advantages and disadvantages of the various motor technologies - everyone is too busy trying to keep up the Kardashians to learn anything technical. We are just a dumbing down society...that's just a fact. If you've ever tried to sell something that requires some education of the public it really resonates as a hard truth.
Bosch makes DD hub motors for mopeds with regen so they know for some applications (pretty much anything that goes faster than 15mph) is better on a hub than a mid. You have to consider the mechanical efficiency of the drive system when you compare a mid to a hub drive. Mids are great a slow speed climbing because the gear ratio of the drive system is typically helping the motor but at high speeds the gear ratio is robbing torque from a mid. DD and geared hub deliver torque directly at the rear wheel. While they may sometimes have lower peak / stall torque at high speeds they are usually putting more torque to the rear wheel and most like more efficiently than mids when mechanical losses are considered.
If the bike has a rear suspension then the added unsprung weight of the wheel does impact how well the wheel remains in contact with the road. This "unsprung" debate isn't really about comfort its a big factor when you ridding downhill off-road because you want rear wheel staying in contact with the ground. This is where mids excel but on the street that really has no advantage (rarely if ever is the rear wheel not in contact on a road bike).
The context of this debate is very very important because the suspension of an off-road bike is about keeping the wheels in constant traction contact (not about comfort really). On a street bike a suspension it typically about comfort but I tend to think that tire in the 2.0 - 3.0 width range have enough suspension property that suspensions any street bike that doesn't assist past 30mph (or even faster) are mostly marketing for the masses (to get them to buy something that will just add upfront and service costs to the purchase.
So long as there are people that make a living in marketing, sales, and bean-counting there will be claims made that simply are not true (those that don't create, tend to fabricate to give the sense they are contributing to design). I think we all know marketing isn't about telling the unbridled truth.
DD Hub motors are actually the most economical to produce. Those brands you mentioned just make bigger margins but those are bikes intended for higher speeds where DD hub motors shine.
It's all about application. If someone just wants to leisure ride around their neighborhood at 10 mph max get a mid and you'll be very happy. If you want to do some commuting with a purpose (ie replacing your car with an ebike) you should really give both DD motors a spin and compare to the geared hubs as well which will have a bit better low speed performance but maybe not as good at the higher speeds in the 30mph range.
tomjasz
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This!
Captain Slow
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All this discussion about regen, did anyone see the post Ravi made about regen in another part of this forum? Tons of information there.
tomjasz
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Hard to keep up with everyone's input. Links help others if you know where the thread is.
Thanks for the tip!! https://electricbikereview.com/forums/threads/regeneration-on-e-bike-motors.29172/
Captain Slow
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Thanks Thomas
Pragmatic
Member
Deleted Member 4210 Well darn!! Pragmatically, whether stopping/slowing in a truck or on a bike, I just hate the inefficiency of turning kinetic energy into waste heat (hot pads and hot rotors).
But as mentioned, the weight- transfer-driven dynamics drives the greater braking of the front wheel/hub, that makes rear-hub motor, or mid-powered (still rear wheel via chain) makes regen inconsequential/impractical. Again, darn! ...Ride On!!!
But as mentioned, the weight- transfer-driven dynamics drives the greater braking of the front wheel/hub, that makes rear-hub motor, or mid-powered (still rear wheel via chain) makes regen inconsequential/impractical. Again, darn! ...Ride On!!!
AHicks
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Pragmatic, the amount of regen available with most systems will not be a weight transfer event. For weight transfer to be anything of any consequence, you would need something like the GMAC drive, and some very heavy duty circuitry from the motor to the battery cells to handle that kind of current. With today's bikes, that kind of regen is going to smoke most systems not designed to handle very large amounts of power.....
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