Regen

[john]

Hi.....

First post and lots of questions for you guy's

When Brammo's are breaking... is the Electric Motor currently able to act as a dynamo supplying charge to the batteries ?

And Brake pads... does any company offer energy harvesting break pads - Thermo-Electric

Front folks .... http://web.mit.edu/newsoffice/2009/shock-absorbers-0209.html ??

[Brammofan]

Regen braking has been addressed before:
"Why the Enertia lacks Regen Braking" and "More on why the Enertia lacks regen braking."

Basically, Brammo did not design the Enertia with regen braking, but perhaps it could be modified to include it with an aftermarket device.  However, the amount of energy you could put back into the batteries with regen braking is not enough to justify the cost, increased complexity, and risk of loss of traction.

That MIT fork looks interesting, but the article is from a year ago and I haven't heard of anyone putting it into their bikes.  Innovations will come in time, I'm sure, but right now they probably think the bike has enough innovations. 

Welcome to the forum, by the way. 

[john]

Great... Thanks... answered my question perfectly.

So... What about Thermoelectric generators ? http://en.wikipedia.org/wiki/Thermoelectric_generator

Something like this built into a brake caliper ? .... So its not a unpredictable and thus dangerous kinetic load on the braking system but a highly predictable heat exchange = regen.

[Phantom]

Can you find a calculation of how much by-product heat you need to get 1Kw?

Initially, I do not think there is enough heat being generated from stopping a motorcycle due to its low mass.

[Richard230]

Just to add another regen comment: my GPR-S came with a sepex motor and regen. Last week, before finally giving up on trying to repair my EMS GPR-S and giving it to my son-in-law for him to try to puzzle out its problems, I defeated the regen feature on the bike by reprogramming the Sevcon controller.

After riding it around in an attempt to see if the regen was causing its stalling problem (apparently it wasn't), I decided that I preferred the bike without regen. Normal braking gives a more even feel to the braking process, resulted in much less weird current fluctuation on the Cycle Analysis screen and I prefer being able to gently coast to a stop instead of having the motor do the braking for me. So, based upon my experience with regen on a lightweight motorcycle, I would recommend against it. However, it might be more useful on a much heaver automobile or truck. On my bike, the amount of additional range using the regen feature typically was in the area of between 1 and 3% - not much on a vehicle with a 30 mile maximum range.

[protomech]

Per wikipedia, a thermoelectric generator has typical efficiency around 5-10%. Not worth bothering with imo - using the motor as a generator should be 60-80% efficient, depending on how well the batteries accept high charge rates.

Energy recovering shocks would be quite cool. I bet these are still in the prototype stage, and they sound like they work best for heavy vehicles - the mit article discusses using them for large trucks, military vehicles, 18 wheelers.

The Empulse is perhaps the most refined and productized of the near-term electric bikes available in the short term, but still has a great deal of room for improved efficiencies. Think of a 50 mpg 1984 Honda CRX HF vs a 50 mpg 2010 Toyota Prius. Brammo is basically releasing the EV bike version of the CRX - a solid bike using advanced components, but without significantly advanced control systems ($$$ to develop and get "right", see Richard230's GPR-S). Those control systems will come with time and increasing market, and I would not be surprised to see advanced control systems be a significant discriminator between the smaller manufacturers (Brammo) and the big motorcycle companies (Honda..).

[john]

Per wikipedia, a thermoelectric generator has typical efficiency around 5-10%. Not worth bothering with imo -

Its all power.....  and at the brake calipers very simple and cheap to install without interfering with traditional 'known' safety design related to braking. ie. the installation of thermoelectric harvesting at the caliper (or possibly the pad itself) in no way changes the dynamics of the braking system from a standard bike.

Don't get me wrong.... The Brammo approach is 100% right.... including technical design leading to a Bauhaus like form following function beauty. (especially with the Empulse) The Empulse is stunning in naked form... but that's why its go SO much potential... Imagine the clothes you could design around it ? You want a Will Smith iRobot style or Tron like look, no problem ! etc etc