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Messages - liveforphysics

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1
Zero Motorcycles Forum | 2013+ / Re: charging networks
« on: November 01, 2017, 01:55:28 AM »
You worked out the correct thermal energy transfer rate. As thermal energy doesn't twist a shaft without some inherently very lossy conversions to shaft power, our charge rate taking on equal 'traction useful' energy is about 3.5-4x better than your estimate.  However, this just means faster dripping, and I agree whole heartedly that a modern EV charge infrastructure needs to be shifted up at least a full order of magnitude in charging power rates.

The 32amp 220vac J plug stations are a brilliant play by SAE (the oil companies RnD front) to ensure all the infrastructure being installed today (aside from Tesla superchargers and CHAdeMO etc) offers only the cosmetic gesture of charging rather than being useful infrastructure to enable an all EV future.

I try not to stop to charge unless it's a site I can tap 3 Jplugs minimum and max them all out, and this still seems inadequate for a motorcycle....


Quote from: BrianTRice on October 31, 2017, 04:12:06 AM
I'll do a little back-of-the-napkin calculation for the sake of argument and since I just got back from a somewhat challenging Zero trip where I had a lot of time to think:

Given the energy equivalent of 33.4kWh/gal for gasoline/petroleum (per https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent):

11.4kWh (nominal) amounts to 0.341 gal of petrol.

A 1C charge rate then is 0.341 gal/hr or 0.005688 gal/min * 768 teaspoon/gal = 4.368 teaspoons of petrol equivalent per minute.

That's 0.07 teaspoons of gasoline per second, and there are roughly 100 drops in a teaspoon, which means you could watch the same energy transfer by watching single drops of gasoline fall from a spigot!

And on top of that, in some places you can only get this drip rate once every 60-100 miles (RV parks' 50A plug if it works fully) for a connection fee of $10 ($5 or free with minimal persuasion, but you get the idea).

So, yeah, gasoline is massively more convenient right now with a huge stack of infrastructure supporting in and spent just distributing it. I spent a few times during my trip mentioning how a Tesla with the largest purchasable battery of 100kWh yields the energy equivalent of 3 gallons of petrol. The electric infrastructure in the USA is only barely ready to support EV usage, and it helps a lot to have Tesla's and other auto manufacturers' weight thrown behind charging network buildout.

2
Zero Motorcycles Forum | 2013+ / Re: #DubJay Charging
« on: May 16, 2017, 02:35:07 AM »
Nice job sir!  That's a reasonable set of plugs!

3
Zero Motorcycles Forum | 2013+ / Re: Big belt Kits for pre-2017 bikes.
« on: January 07, 2017, 01:23:34 PM »
I can vouch that Farfle is legit, figured out what it took to do the small radius sprocket profile right, and I will be running the 18t sprocket for my own DSR to be a wheelie-machine! :-)

4
Pics and Vids / Re: Zero S test ride
« on: December 02, 2014, 01:41:04 PM »
Quote from: teddillard on November 19, 2014, 12:26:14 AM
Quote from: Biff on November 18, 2014, 06:12:47 AM
Quote from: teddillard on November 11, 2014, 12:13:26 AM
Stall torque and it's effect on 0 RPM performance is not a theory, just to be clear.  Given that, you're talking about two different things - acceleration from 0 RPM, and acceleration from well onto the torque/power band to a higher RPM. Seems like it'd be hard to measure, but if it's the case, it would certainly suggest throttle mapping, which it sounds like we've confirmed is what Zero is doing. 

My suspicion is that they're concerned with riders who are unaccustomed to riding without a clutch.  Most experienced riders will use the clutch to feather power off the line, even during hard acceleration on the power band, and in some cases use it for low-speed control of power.  You don't have that kind of option with an electric motor. 

Please stop proliferating this rumour, It is not true.  ...

I'm not "proliferating" anything, and certainly not what you call a rumor.  I think it's fairly clear if you read my comment that I have nothing but a suspicion and suggestions.  I'd certainly like someone with credentials and evidence to get on and put it to rest, and I'm certain there are more than a few who read this who could. 

The only dog I have in this fight is the fact that different types of motors have different stall torque characteristics, period.  Does the Energica motor have lower stall torque than a similar (100kw or so) PMDC motor?  Yes.  Is that why I couldn't wheelie it?  No clue.  I have no idea if it was mapped or not, and I really don't care. 

Quote from: tyskmoped on November 19, 2014, 12:23:42 AM
Believe what you like but the same vehicle with more horsepower will accelerate faster. Even if the motor has only 10% of the torque, because at same wheel speed you will have more wheel torque if geared for same top speed.

As far as horsepower goes, you need to have a really basic understanding.  Horsepower = (Torque x RPMs) / 5252.  End of discussion.  http://danielmiessler.com/study/horsepower/  So explain to me how you can have a vehicle with 10% of the torque and more horsepower.

Ted- You are mistaken.  Biff is trying to set you straight.  Biff knows this better than any other human on earth I have awareness of, you would be wise to listen rather than continue spreading falsehood.

5
Zero Motorcycles Forum | 2012 and older / Re: Real World Range 2012 S ZF9
« on: February 11, 2012, 05:48:07 AM »
I also am not a fan of noisy fans disrupting an otherwise almost silent riding experience, so we spent the extra effort to create entirely passive cooling systems for the battery and charger both, and made the motors fan integrated with the shaft so it only spins and makes noise when the motor shaft is spinning. 

Combined with the belt drive and the sine-wave AC drive to the motor, it makes for a really Zen-like quiet riding experience. 

The biggest factor on your riding noise becomes choosing a helmet that has excellent low-wind-noise performance.

It adds a little bit of weight and cost and heat-sink bulk vs having fans, but the silence and simplicity makes it all worth it IMHO. :-)

6
Zero Motorcycles Forum | 2012 and older / Re: Real World Range 2012 S ZF9
« on: February 11, 2012, 03:57:26 AM »
Yep.

7
Zero Motorcycles Forum | 2012 and older / Re: Real World Range 2012 S ZF9
« on: February 10, 2012, 11:16:20 AM »
The fan is mounted internally to the shaft of the motor on the backside. 

8
Zero Motorcycles Forum | 2012 and older / Re: are zero using the Nano Tech battery by Turnigy?
« on: February 10, 2012, 12:49:53 AM »
The Zero battery is designed with maximum safety and longevity as priority #1, followed closely by energy density.   

Nanotech cells offer extremely poor safety and consistency and reliability.  They are amazing for EV racing and RC, but you would not want them in much else.

9
Zero Motorcycles Forum | 2012 and older / Re: Real World Range 2012 S ZF9
« on: February 09, 2012, 07:48:49 AM »
Battery temp has a range impact.   The warmer the pack, the happier it will share it's contained energy.


However, body position has a major impact. 

In highway testing, you could easily see a >30% difference in range between tucked properly and sitting upright like a wall.


Your BMS will protect the pack from over-discharge, and it leaves a healthy margin of room at the top and bottom of capacity to protect itself from overly deep-cycling that would effect the cells lifespan. 

Also, you will find if you reach the blinking last bar of the pack, you have about ~5-10miles left of "get-you-home" capacity at a reduced performance level, but it's way better than walking. ;-)  No more abrupt cut-offs.

You're welcome. :-)

10
Zero Motorcycles Forum | 2012 and older / Re: Windshield Makes a Difference
« on: February 09, 2012, 07:31:19 AM »
If you desire as much speed as possible, you can reach >92mph on your machine on a warm day (because air resistance is lower and the battery performs substantially better), if you put your body in a proper racing tuck, meaning elbows tucked in, legs and feet tucked tight, chin to the bars, etc.   It's not very comfortable obviously, but if you're ever begging for an extra couple MPH, the bike will do it with the right rider position. 

Fully upright on a motorcycle, a rider is kinda like a drag parachute, and you can easily see a 5-10mph difference just from rider position.

On my GSXR-1000, I can't go over ~150ish if I'm sitting even a tiny bit upright.  Lay flat to the tank and she has another 25mph in her.

11
Zero Motorcycles Forum | 2012 and older / Re: are zero using the Nano Tech battery by Turnigy?
« on: February 09, 2012, 07:25:37 AM »
No Zero product uses Nano-tech cells.   

That is my personal bicycle made for racing and general hooligan activities.


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