variable regenerative braking

[Paul Gordon]

Just a quick question, (I think I can guess the answer but here goes anyway)

I live in the Alps and my wife refuses to ride here because of the massively scary descents, not to mention the climbs!
Q. Is there an electric bike on the market which uses the motor as a generator to recharge the battery and in this case more importantly, slow the bike down without having to use the brakes. I appreciate that "engine braking" is normally set at a fixed rate and hence getting limited benefit from regenerative breaking but surely you must be able to use the speed controller in a similar way to apply more or less regeneration and hence more or less engine braking???

If such a product doesn't exist then perhaps some electrical boffin might like to try and develop it PLEASE!

Thanks

Paul

 

[flecc]

There have been a few Paul, but since an e-bike's mass regenerates very little, when judged by that factor they haven't been popular.

Panasonic did recently introduce one front hub motor bike with a full acting braking motor, but it's never emerged from Japan where it had a 3000 bike trial marketing.

The most notable motor for what you want is the Bionx rear hub motor which has four switchable levels of regenerative braking, as well as four levels of drive power. So any e-bike with that motor will be ok for your wife. However, be aware that they are not cheap and their specific batteries are very expensive and cannot be substituted with other batteries.

It's available as a kit and some new e-bikes have had it as standard, but offhand I don't know which ones. Perhaps others will know. Meanwhile if I find one I'll post again.

You should be also able to find a Swiss dealer who will fit a Bionx kit to a bike of your choice.
.

 

[trex]

...
surely you must be able to use the speed controller in a similar way to apply more or less regeneration and hence more or less engine braking???

If such a product doesn't exist then perhaps some electrical boffin might like to try and develop it PLEASE!

Thanks

Paul

yes, there is. But there is nothing like a cost free solution. Regenerative braking is only available on direct drive motors because they don't have clutch, so the coils will drive the wheel or the wheel drives the coils.
Those motors are very inefficient hill climbers. Furthermore, powerful regenerative braking is difficult to design because most batteries are asymetrical, they give high discharge current and take small charge current, about 10% of what they are capable of discharging. You end up by creating a lot of heat inside the motor when using high power regenerative braking, not a good thing.

 

[flecc]

Trex is absolutely right about the DD motors that these systems use. However, the Bionx motor can climb quite well on it's level 4 power setting, but at the cost of a shortened range. Owners report about 18 miles on their largest battery in mixed territory using this setting when necessary, but very long continuous climbs will shorten that further.
.

 

[cwah]

Kelly is going to have variable regen soon. I'll buy from them.

Adaptto does it too and is better but overpriced to my mind

 

[EddiePJ]

Variable in as much as you can turn it on or off. http://eu.industrial.panasonic.com/products/e-bike-systems/rear-hub-unit-system used on a couple of KTM pedelecs, including my e-Race P

 

[danielrlee]

Kits based around the Grinfineon controller from ebikes.ca will give you fully proportional regenerative braking.

www.ebikes.ca

 

[Paul Gordon]

Many thanks for the answers, seems like I am spoilt for choice.

Paul

 

[RobF]

I think the Oxygen MTB - and possibly other Oxygen bikes - has switchable regenerative braking.

 

[flecc]

I think the Oxygen MTB - and possibly other Oxygen bikes - has switchable regenerative braking.

No, it's an internally geared BPM-CST motor on the MTB Rob, not Direct Drive.
.

 

[RobF]

No, it's an internally geared BPM-CST motor on the MTB Rob, not Direct Drive.
.

That's odd, I would have sworn I played with some form of regen on the test ride.

Or perhaps I'm thinking of the brief go I had on a KTM/Panasonic like Eddie's.

 

[flecc]

That's odd, I would have sworn I played with some form of regen on the test ride.

Or perhaps I'm thinking of the brief go I had on a KTM/Panasonic like Eddie's.

That will be it Rob, the Panasonic rear hub motor is definitely a DD motor with regen and braking. It would be difficult to design, but there could be a market for a freewheeling internally geared motor that had the ability for the rider to lock the internal freewheel to get regen and braking on downhills.
.

 

[Wicky]

I can confirm the KTM eRace Panasonic has regen. Here's the manual about the console settings

 

[trex]

Blewit post:

Just a note regarding the Panasonic PCT hub motor. It is not a direct drive, there is reduction gearing within the hub. What is missing, is a freewheel clutch, thereby allowing regenerative braking. The reduction gear ratio is biased in favour of hill climbing.

 

[EddiePJ]

I can confirm the KTM eRace Panasonic has regen. Here's the manual about the console settings

I noticed earlier that it appears that KTM have dropped the e Lycan P from the 2016 line up. It seems as though there is now only two Panasonic bikes in the line up.

 

[flecc]

Blewit post:

So uniquely a third hub motor type, high efficiency direct drive. Surprising perhaps that others haven't copied.
.

 

[oldtom]

On all my EAPCs, power from the motor disappears at a smidgin above 15mph. None has a geared motor, all are silent, yet are perfectly adequate hill-climbers if not the ultimate examples in that particular department.

Curiously, the often ignored and wrongly-criticised DD rear hub motor is the most powerful of my bikes but any bicycle motor's performance is dependent on the current supplied and the voltage of the battery. The Xion unit, de-tuned for the European market, is an excellent performer and a great example of an EAPC.

Equipped with energy-recovery, broadly disregarded for its lack of usefulness by many including myself, I have taken the view that it is better deployed as a rim-saving braking tool and in that regard, I find it works.

Some manufacturers may dally with the technology a bit longer but I fear energy recovery on EAPCs as we know them is unlikely to prove worthwhile in practice in the foreseeable future.

Tom

 

[OldBob1]

Unless a better battery system appears.

 

[trex]

...
Curiously, the often ignored and wrongly-criticised DD rear hub motor is the most powerful of my bikes.

from the Xion manual:

12 Nm rated torque
41 Nm maximum torque

Even the 41NM figure is not great compared to the 8-Fun BPM and many popular crank drive motors. That torque figure is produced also at low efficiency.

 

[oldtom]

from the Xion manual:

12 Nm rated torque
41 Nm maximum torque

Even the 41NM figure is not great compared to the 8-Fun BPM and many popular crank drive motors. That torque figure is produced also at low efficiency.

And your point is?

Tom