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[benswing]

Hey, we get a shout out in this well-written Giz Mag article about Zero Motorcycles.

http://www.gizmag.com/zero-electric-motorcycles-factory-2015/35865/

If you have been following this forum there isn't much new information, but if you are relatively new this is a great summary of Zero and the current state of their motorcycles.   It includes sections on the battery, charging, management philosophy, and gives nods to Terry Hershner and Craig Vetter. 

[Richard230]

I found that article really interesting.  It appears that Zero now has twice the number of employees that they had when I visited the factory in 2012.  Plus, it explains why they had such crappy chassis components and brakes in previous years and why they use the type of battery and voltage that they do.  It also comments that the output from the Tesla Gigafactory output isn't going to help electric motorcycles much and winds up with a comment that they are looking into a fully faired touring motorcycle that could get up to a 30% increase in range.   

[benswing]

Zero doesn't state it outright in the article, but it says a fairing is something Zero "is considering".

[BrianTRice@gmail.com]

I like pieces like this; they're interesting to analyze. Zero wants to project its successes, but it wouldn't say anything that would give away strategic value. The discussion about charging and voltage is interesting:

So why not go up to a higher voltage that would work with the existing charging infrastructure? "If we went to 300 volts, it would hurt you on every front that matters," says Zero's Senior Battery Specialist Luke Workman. "We'd have lower efficiency, lower power, higher cost, higher drive train heat – and in terms of life safety for the guys that are working on these things, you go from a nasty tickle … to dead. The majority of electric vehicles that are using higher voltages are doing so simply because they've been designed using legacy equipment. You'll see a lot more EVs going low voltage in the future."

They're positioning the high-voltage bike vendors as not taking a pragmatic approach, and casting their interactions with charging vendors as being quite reasonable ("please support the voltages in the standard, and you'll gain happy customers"). That speaks to the CHAdeMO problem, but avoids talking about an L2 J1772 charger, which I suppose is less desirable from their perspective, to add complexity to the charging story.

I have enough background (former nuclear electrical technician) to appreciate the safety comment, especially because they have a dealer network strategy (imagine how hesitant a career motorcycle mechanic will be to work on a bike with such voltage), but can't speak to the implications about efficiency and power. Surely higher voltage means more power per amps delivered, right? What's the factor I'm missing, maybe arcing risk in motor windings?

The fairing comment is clearly a concrete and easy option for them to take soon, and they want to leave wiggle room for whatever 2016 decisions get into the engineering pipeline. I can definitely appreciate both.

[benswing]

I appreciated that they are focusing on fast charging such as ChaDeMo instead of a J1772 interim solution.  Going straight to fast charging is one of the things that Tesla has done very right, and it's the only way to address the range issue reasonably.  The J1772 gear that we use now is just an interim solution.  The question is, how long will the "interim" last?  Right now it seems that it will take some years before we have a charging standard.

[Doug S]

Right now it seems that it will take some years before we have a charging standard.

Semantics, but ChaDeMo IS a standard, and if it were adhered to, it would be a very nice solution to our needs, in my opinion. I live in San Diego, and if all the stations did adhere to the standard, ChaDeMo would allow me to roam from Santa Barbara to the Mexican border, and as far east as Palm Springs, riding for an hour, then charging for an hour...which isn't a bad schedule for a leisurely cruise. I haven't looked, but I'd guess the situation in the SF area is similar. Another couple more years, a few more stations midway up the coast, and I could make a day-long ride up to Santa Cruz and tour the Zero factory....if only the standard was enforced! At that point, the adapter would be well worth $1800, in my mind. With the current state of affairs, not so much.

[protomech]

I appreciated that they are focusing on fast charging such as ChaDeMo instead of a J1772 interim solution.  Going straight to fast charging is one of the things that Tesla has done very right, and it's the only way to address the range issue reasonably.  The J1772 gear that we use now is just an interim solution.  The question is, how long will the "interim" last?  Right now it seems that it will take some years before we have a charging standard.

Tesla didn't go straight to DC quick charging. The Roadster was designed for high-amp AC charging (and disappointing rumors are that the Roadster upgrade will not include SC compatibility). But Tesla did not have the capital and the Roadster was never going to be a sufficiently high-volume vehicle to roll out a useful DC quick charge network in 2008. They clearly recognize the importance of DC quick charging to replace ICE infrastructure: it's at the top level of their website along with Model S and Model X, and BMW/Nissan are struggling against their own inertia to rollout similar networks.

Early modern EVs had to have onboard chargers to meet the consumer expectations of being able to charge away from home (even if only on 120V AC). And once EVs had these onboard chargers with a standard interface, low cost at point-of-charge dictated that AC charging would be overwhelmingly preferred by homes and businesses installing equipment. Most of the J1772 EVSE installations in the US are poorly sited IMO, and see little utilization; workplace and multi-hour destinations (movies / sporting events / parks) are the only things that really make sense in a future that will be filled with 30 to 50 kWh EVs.

Eventually the DC quick charging infrastructure may be sufficiently reliable that there will be little or no need for onboard chargers, as with the EVs in the late 19th and early 20th centuries. But it honestly would have taken a state-level funding commitment to roll that out before the vehicle marketplace was ready for it.

I like pieces like this; they're interesting to analyze. Zero wants to project its successes, but it wouldn't say anything that would give away strategic value. The discussion about charging and voltage is interesting:

So why not go up to a higher voltage that would work with the existing charging infrastructure? "If we went to 300 volts, it would hurt you on every front that matters," says Zero's Senior Battery Specialist Luke Workman. "We'd have lower efficiency, lower power, higher cost, higher drive train heat – and in terms of life safety for the guys that are working on these things, you go from a nasty tickle … to dead. The majority of electric vehicles that are using higher voltages are doing so simply because they've been designed using legacy equipment. You'll see a lot more EVs going low voltage in the future."

They're positioning the high-voltage bike vendors as not taking a pragmatic approach, and casting their interactions with charging vendors as being quite reasonable ("please support the voltages in the standard, and you'll gain happy customers"). That speaks to the ChaDeMo problem, but avoids talking about an L2 J1772 charger, which I suppose is less desirable from their perspective, to add complexity to the charging story.

I have enough background (former nuclear electrical technician) to appreciate the safety comment, especially because they have a dealer network strategy (imagine how hesitant a career motorcycle mechanic will be to work on a bike with such voltage), but can't speak to the implications about efficiency and power. Surely higher voltage means more power per amps delivered, right? What's the factor I'm missing, maybe arcing risk in motor windings?

You can deliver the same power at high volts / low amps or low volts / high amps. High amps means you need thicker conductors, but I think that's perhaps less of a concern than it appears. DC quick charging supply equipment would need massive cables - 130 kW for a 100V EV would require cables twice as thick as the current Supercharger cable. I'm not sure what he means by lower power, lower efficiency, and higher heat.

I'm also skeptical about EVs going lower voltage in the future. If nothing else, the current charging standards dictate high voltage vehicles, and eventually motorcycles will conform to the charging standards dictated by the vastly more numerous EV cars.

[Doug S]

I'm not sure what he means by lower power, lower efficiency, and higher heat.

As an EE, I'm pretty sure he's talking about the realities of engineering today. You're right, the same amount of power can theoretically be delivered by half the current at twice the voltage, but you have to take into account what devices (power bipolar transistors, MOSFETs, IGBTs, thyristors or whatever they're using) are readily available to build into an inverter with those design specs.

And of course, as mentioned, there's a very real safety concern above a certain voltage level (on the spectrum, I'd describe 100VDC as "reasonably safe" but 300VDC as anything but), so if you CAN design a system at 100V instead of 300V, it's preferred. Development in the power semiconductor field these days is constantly giving us devices capable of handling higher and higher currents, so I'd agree with his contention that tomorrow's Tesla may well reconfigure their battery pack for lower voltage at higher current (i.e. more batteries in parallel, fewer in series). Sure, you'd have to use thicker wire, which would weigh a little more and cost a bit more, and you'd have to redesign the motor accordingly, but the safety benefits are more than worth it.

[BrianTRice@gmail.com]

I'm not sure what he means by lower power, lower efficiency, and higher heat.

As an EE, I'm pretty sure he's talking about the realities of engineering today. You're right, the same amount of power can theoretically be delivered by half the current at twice the voltage, but you have to take into account what devices (power bipolar transistors, MOSFETs, IGBTs, thyristors or whatever they're using) are readily available to build into an inverter with those design specs.

And of course, as mentioned, there's a very real safety concern above a certain voltage level (on the spectrum, I'd describe 100VDC as "reasonably safe" but 300VDC as anything but), so if you CAN design a system at 100V instead of 300V, it's preferred. Development in the power semiconductor field these days is constantly giving us devices capable of handling higher and higher currents, so I'd agree with his contention that tomorrow's Tesla may well reconfigure their battery pack for lower voltage at higher current (i.e. more batteries in parallel, fewer in series). Sure, you'd have to use thicker wire, which would weigh a little more and cost a bit more, and you'd have to redesign the motor accordingly, but the safety benefits are more than worth it.

That's pretty interesting; I remember testing cabinet-sized power inverters meant for nuclear submarines in the mid-90s, and wound up learning the limitations of that generation of IGBTs. It wouldn't surprise me now that you've framed it that way that this is a big constraint an engineering team faces with these powertrains.

[Doug S]

It wouldn't surprise me now that you've framed it that way that this is a big constraint an engineering team faces with these powertrains.

Well, you have to keep in mind that this is commercial hardware, not military hardware like your nuclear submarines were. They didn't have any concerns about price, size, weight or heat dissipation. EV manufacturers have to worry about all those things and more.

In the commercial world, it's all about price, packaging and reliability. Just thinking about trying to package the motor inverter in a compact, lightweight, cheap package that quickly and efficiently dissipates all the heat it generates makes my head hurt.

[BrianTRice@gmail.com]

Just thinking about trying to package the motor inverter in a compact, lightweight, cheap package that quickly and efficiently dissipates all the heat it generates makes my head hurt.

This simply is the best case for explaining how great it is that these work as well as they do! All good points, and I work in the commercial world now (software, mainly) so understand your points.

[CrashCash]

I just ran into a guy that read this article and was surprised to see my SR on the street.