Comparing the Empulse with the 2013 Zero

[flar]

I don't view the transmission as a short-term solution at all.  Even with a high-voltage system, the ideal solution in my mind (although there are many others that would disagree) would still incorporate a multiple ratio gearbox (maybe or maybe not 6 gears).  It's very good way to get significant torque production with a smaller overall system.  A direct-drive, high voltage system would be "good-enough" for most riders, but it would still not maximize the available performance (again - my opinion). 

At some point, though, you can build a small enough motor that produces so much power that even geared for 100+MPH it is in risk of smoking tires and getting squirmy at launch.  Certainly Tesla is in that ballpark where they are beating all but the fastest overpriced sports cars and still making 130MPH.  At that point, how big, exactly, is the market they would be targeting by adding the weight and complexity of a gearbox for even faster launches?

As to how close the motorcycle technologies might be to that same turning point, I don't have a lot of industry knowledge.  But, I have measured the 2013 Zeros with a butt dyno and they made huge inroads in this past year.  That same butt dyno tells me that my Empulse still beats them, though, and their high-output endurance is still unspoken for - but I'm curious as to how long it will take to bridge this gap.

I hear you on the value of gears, and I have plenty of ICE car experience that makes me wary of giving up that control over mechanical advantage, but only because ICEs exaggerate a shortcoming that electric motors don't really suffer from.  If a gearbox gets me from 4s 0-60 down to 3s 0-60 that's nice, but not really useful or a selling point for me.  At highway speeds where I care, gears won't have the same amplification ratio if they aren't covering up for a narrow power band.

[Richard230]

I continue to be fascinated when my Zero in slow-mo Eco mode takes off from a stoplight faster than the 300 hp SUV, pick-up truck, or Lexus next to me.  There are lots of people buying vehicles with lots of expensive, fuel-inefficient, horsepower who never use it.  I just don't get it. 

Beyond a certain number, a lot of horsepower seems like a waste to me if you don't bother using it.

[protomech]

You're pretty close.  Here are some comments from our lead motor guru, Dan Riegels:

Power factor is way too high, closer to 75% at Pmax.  Efficiency is good.  The only limitation is cooling.  The 2min and 10sec rating are assuming a certain level of cooling.  Voltage sag quoted is closer to 5C+.  Low PF puts a lot of load on the controller.

I would tell you more... but then I'd have to either hire you or kill you...

Well, I'd have a lot more fun with one of those than the other

I'm curious how much power factor is a design consideration .. particularly if it generates a lot of heat = waste energy in the controller. Does the Empulse only liquid-cool the motor? I recall reading the battery modules have fins for air-cooling.. does the controller likewise benefit from air flow while in motion?

I don't view the transmission as a short-term solution at all.  Even with a high-voltage system, the ideal solution in my mind (although there are many others that would disagree) would still incorporate a multiple ratio gearbox (maybe or maybe not 6 gears).  It's very good way to get significant torque production with a smaller overall system.  A direct-drive, high voltage system would be "good-enough" for most riders, but it would still not maximize the available performance (again - my opinion). 

At some point, though, you can build a small enough motor that produces so much power that even geared for 100+MPH it is in risk of smoking tires and getting squirmy at launch.  Certainly Tesla is in that ballpark where they are beating all but the fastest overpriced sports cars and still making 130MPH.  At that point, how big, exactly, is the market they would be targeting by adding the weight and complexity of a gearbox for even faster launches?

Regarding smaller overall system - flar, what are your impressions about the Parker + IET motor size combination on the Empulse vs the Zero 75-7 motor on the 2013 Zero S?

I'd love to have a two gear setup on my 2012 Zero (maybe 20% lower and 20% higher). But looking at torque plots from Hollywood Electrics and their Sevcon Size 6 upgrade, I think I'd get just as much performance that way.

Another point of comparison is the Enertia Plus vs 2013 Zero XU. Zero XU has a larger motor and weighs a fair bit less, runs 0-60 mph in a claimed 5-6s. IET would help the Enertia's performance, but it seems like a motor upgrade would serve it even better. Possibly a motor upgrade + IET would give it superior performance to the XU ..

I continue to be fascinated when my Zero in slow-mo Eco mode takes off from a stoplight faster than the 300 hp SUV, pick-up truck, or Lexus next to me.  There are lots of people buying vehicles with lots of expensive, fuel-inefficient, horsepower who never use it.  I just don't get it. 

Beyond a certain number, a lot of horsepower seems like a waste to me if you don't bother using it.

ICE tends to be most efficient under moderate-high, constant load. That's part of why hybrids are so successful - the electric motor can completely take over all traction power during light load periods, and they deliver adequate performance from an undersized engine that will be under higher relative load than a conventional ICE.

While electric motor efficiency maps aren't exactly flat, they're a fair sight better than ICE efficiency maps.. so we see the 2013 Zero bikes doubling power and delivering markedly better efficiency. That's crazy talk in ICE land.

[flar]

At some point, though, you can build a small enough motor that produces so much power that even geared for 100+MPH it is in risk of smoking tires and getting squirmy at launch.  Certainly Tesla is in that ballpark where they are beating all but the fastest overpriced sports cars and still making 130MPH.  At that point, how big, exactly, is the market they would be targeting by adding the weight and complexity of a gearbox for even faster launches?

Regarding smaller overall system - flar, what are your impressions about the Parker + IET motor size combination on the Empulse vs the Zero 75-7 motor on the 2013 Zero S?

I think the Parker+IET still feels better, but it is not night and day.  Also, a fair bit of that is how willing it is off the line whereas the Zero feels like it is easing you into it.  The Zero does pick up so much torque and soon enough that it isn't just "weak at the low end" and I know that they reprogrammed the 2012's to have a mild roll-on to keep the power requirements down, but the Empulse just launches you without any babying or drama and that is noticeably more fun and powerful feeling.  Perhaps Zero needs to have that easement to keep their power system happy?  Or are they doing it for safety?  Either way, it's not crippling and it is still a lot of fun, just not quite as authoritative as the Empulse's launch behavior.

At 5MPH rollon, I'd have to ride them more back to back than an hour apart like I did to really answer that question.  At highway speeds the Zero did not feel weak at all when simulating a passing maneuver, but I'm sure if I picked the right gear (or two), then the Empulse would probably pull a little more strongly.  But, that is quite a bit different than "having to be in the right gear at all or just go home" for an ICE.

So, from the butt dyno perspective - if we were to freeze motor development at last year's levels (judging from riding a 2012 Zero), I'd say the IET was totally worth it without question.  If we were to freeze motor development at this year's selection I'd say that the IET gives the Empulse the edge and you can decide if that edge is worth having to shift gears and replace oil or if you actually like shifting gears (I have been having fun trying to keep it at its efficiency peak on my commute, but I could easily live without that "fun" and it isn't clear how much gain I got from that).  But, motor development is not frozen, is it?

Caveat - only a 10 mile ride on the 2013 Zero, but we did most of Guadalupe Canyon road:

http://goo.gl/maps/TbHhX

And, to put things back into perspective wrt the whole thread - the Empulse just mops the floor here with its sweet suspension and chassis.  Combine that with the fact that the IET still seems to have the edge in performance and there isn't a lot to question about the current model - I'm asking more with an eye towards what will come in the next couple of models on the horizon.

It was definitely not a bad choice for today.
But, will it turn out to be a one-hit wonder?
Or will it turn into a nice option for only the highest performing e-bikes?
Or will we soon go the way of Tesla and everyone will ask "what gearbox"?

I hope my questions don't appear in any way to be a criticism of the current product, though...

[Adan]

I'm now in the position of deciding between the 2013 Zero S v. the Empulse.  I've been happily commuting on my Enertia Classic, but now that we are moving from San Francisco out to Marin, a change is gonna come.  If I take it easy on the freeway, the Enertia actually can make the commute one way, and I can charge at work, but there's not enough margin for mistakes or detours, and I'd feel safer with more freeway oomph.

I test rode the Empulse about 6 months ago, and just recently rode a 2013 Zero S.  I was much more impressed with the Zero than I thought I'd be.  The brakes/chassis/suspension are really all fine.  I loved how light and nimble it felt.  The Zero is not as confidence-inspiring as the Empulse, but it is more than adequate for commuting.  And in that functional context, the Zero gives a lot more bang for the buck than the Empulse.

I think for me it will come down to a personal choice of whether I want my electric bike just for commuting, or do I also want to be tearing up the Marin twisties on it.  Both the Zero or the Empulse can get me from my new house in Larkspur to Tomales and back, and that's some great riding (not to mention oyster-eating).  But maybe I will want to keep doing that on my gas bike anyway.  It's on those recreational rides that I really want to feel the sensations of a gas engine and the freedom of knowing that I could just keeping going if I wanted to. 

Anyway, I've always assumed that if my commute lengthened and the Enertia became obsolete, I'd switch to the Empulse.  Having ridden the Zero, I know feel it's a much tougher decision.

[ttxgpfan]

Thank you for that Adan.

I think the only way to settle this is that a completely stock 2013 Zero S ZF 11.4 and Empulse R (not TTX) are raced in the TT Zero, save for race tires.    Lightweight and larger pack versus race bred chassis and a transmission.

[protomech]

I doubt you would use the ZF11.4 for the short circuit races. It would be perfect for IOM TT though .. probably could podium 4 years ago.

[Adan]

I got to test ride the Empulse R again in a more proper context, a couple hours on twisty mountain roads.  Having recently been on a Zero S, my opinion is that the Empulse chassis is head and shoulders above the Zero.  The Zero feels just as quick, but I was not as comfortable using the power that it had.  In many situations, it felt like the chassis just wasn't up to the task.  The Empulse is a more balanced package and, aside from the clunky transmission (which I feel I could learn to tolerate), feels like a very refined performance machine.