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by liveforphysics
Dec 09 2018 1:02am
Forum: Battery Technology
Topic: 10 times more energy dense!?
Replies: 1
Views: 123

Re: 10 times more energy dense!?

Plausible. It's never been a physics problem to achieve >3,000Wh/kg, just a materials tech and mfg tech challenge.
by liveforphysics
Dec 07 2018 1:37pm
Forum: Motor Technology
Topic: Some random high speed motor winding machines
Replies: 2
Views: 153

Re: Some random high speed motor winding machines

Is there a machine that will do a fat wire? None here. Fat wire MAY get more fill but recently found that if I adjust the pwm frequency to 30,000 I have no audible noise but it seems to be getting into skin effect territory with a 17 aug wire i read. I want to stay at 30,000. Any experience? PWM fr...
by liveforphysics
Dec 05 2018 8:03pm
Forum: Motor Technology
Topic: 4x less coasting resistance
Replies: 21
Views: 724

Re: 4x less coasting resistance

Magnet back iron and is a small fraction of the total iron core losses (eddy + hysteresis).

Stator iron has a major change in flux density everytime a magnet passes by if you're powering the coil or not powering the coil.
by liveforphysics
Dec 03 2018 9:15pm
Forum: E-Vehicles General Discussion
Topic: Wind and Solar vs Coal, Gasoline, Nuclear
Replies: 2917
Views: 99120

Re: Wind and Solar vs Coal, Gasoline, Nuclear

All non-sustainable systems conclude.

The available options have always been 100% sustainable or inherent auto-extinction.

Whatever perception of hardship may be involved in getting there is a pleasantry to experience over continuing the inevitable destination of non-sustainable energy choices.
by liveforphysics
Dec 03 2018 8:56pm
Forum: Battery Technology
Topic: TrustFire 14500 900mAh - trust or not?
Replies: 10
Views: 396

Re: TrustFire 14500 900mAh - trust or not?

+1 The Ultrafire, Trustfire, Holyfire, Bestfire, Uniquefire, don't make any cells. They run a shrink-wrap line for whatever scrap cells are available if you're getting real cells. This is your best case when buying the xxxFire branded re-shrink cells. If you're getting what they make themselves... h...
by liveforphysics
Dec 03 2018 6:07pm
Forum: E-Bike Non-hub Motor Drives
Topic: SURRON LB: RESEARCH & DEVELOPEMENT
Replies: 101
Views: 5875

Re: SURRON LB: RESEARCH & DEVELOPEMENT

I'm excited to see if you can get it to fit, that's a lot of tire!
by liveforphysics
Dec 03 2018 6:00pm
Forum: Battery Technology
Topic: Experimenting with 32v DC fuses at 48v and 68v
Replies: 35
Views: 2261

Re: Experimenting with 32v DC fuses at 48v

Someone told you wrong, because molten glass actually conducts electricity great rather than being an insulator like cold glass. The sand is to absorb energy in the phase change of melting the sand, and it's cheap and works well with the arc pulse quenching of AC currents. My favorite for DC after t...
by liveforphysics
Dec 03 2018 2:01pm
Forum: E-Bike General Discussion
Topic: Is it safe to leave ebikes parked in extreme sun
Replies: 9
Views: 262

Re: Is it safe to leave ebikes parked in extreme sun

RC lipo disposal Slowly drain them to 0v, leaving them plugged on a light (for an example). No matter the resistance that you are using to discharge them, it must draw low enough current to keep them cool during discharge. Once all the cells are at 0v, they are inert and safe to send to recycling f...
by liveforphysics
Dec 03 2018 1:19pm
Forum: E-Bike General Discussion
Topic: Is it safe to leave ebikes parked in extreme sun
Replies: 9
Views: 262

Re: Is it safe to leave ebikes parked in extreme sun

Solar gain temps aren't typically a safety concern, but a major calendar life decay accelerator, as the rate of decay doubles every ~10degC hotter. If you had a pair of the same ebike, and one was stored in a climate controlled garage, and one was parked in direct sun in a hot climate, it would be e...
by liveforphysics
Dec 03 2018 3:00am
Forum: Motor Technology
Topic: 4x less coasting resistance
Replies: 21
Views: 724

Re: 4x less coasting resistance

By reducing eddies and hysties in the rotor then will be an easier coast no? Yes. By looking at the shape of the losses curve, you can see which type of loss is eating your coasting energy. If it's a squared relationship with motor speed, it's eddy related drag, if it's linearly increasing with spe...
by liveforphysics
Nov 30 2018 6:15pm
Forum: Motor Technology
Topic: 4x less coasting resistance
Replies: 21
Views: 724

Re: 4x less coasting resistance

Cogging torque is not what creates the drag when coasting. Cogging torque can be thought of like a ball rolling up and down a ramp as the rotor magnets move in relation to the stator. The ball rolling up and down a ramp has equal energy given back when it rolls down the ramp as it required to roll u...
by liveforphysics
Nov 29 2018 3:14pm
Forum: E-Scooter and Motorcycle Photos & Videos
Topic: Suzuki GSX-R e899 K2
Replies: 298
Views: 28913

Re: Suzuki GSX-R e899 K2

Beautiful bike!
by liveforphysics
Nov 28 2018 6:41pm
Forum: Items for Sale - New
Topic: My first indiegogo for super chargers
Replies: 2
Views: 223

Re: My first indiegogo for super chargers

I can vouch Brandon rocks and his products have been massively useful in charging my Zero DSR for the last 2 years.
by liveforphysics
Nov 27 2018 7:14pm
Forum: Battery Technology
Topic: Another No Solder/Weld 18650 Build (Updated 03/09/2014)
Replies: 343
Views: 54583

Re: Another No Solder/Weld 18650 Build (Updated 03/09/2014)

The bus plates are 0.5mm. I soldered nickel plated contacts onto them. The build still lacks of a housing. Looks so clean, nice job. If you could find a way to eliminate the nickel and make a single stage of copper, or nickel plate the copper (it's actually really easy to do it home with low cost p...
by liveforphysics
Nov 26 2018 11:37pm
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2714
Views: 158440

Re: Sur-Ron - New Mid drive Bike

That's how to win!

Remember to keep your motor phase leads short so the inductance the controller experiences while tuning matches (or close) the representative system inductance. Im excited to see if it can break 30hp with enough tuning.
by liveforphysics
Nov 26 2018 3:40pm
Forum: E-Bike Build Threads / Photos & Video
Topic: Dr_Lulz's 8kw Berg Viper
Replies: 21
Views: 1252

Re: Dr_Lulz's 8kw Berg Viper

Beware of trusting the shrink between cells to keep your series cell groups from shorting due to chaffing from vibration over time.

Looks like a fast fun bike!
by liveforphysics
Nov 26 2018 7:39am
Forum: Battery Technology
Topic: Seeing more 20700s in power tool batteries
Replies: 7
Views: 448

Re: Seeing more 20700s in power tool batteries

Definitely laser welds, and copper is not a bad metal choice for it. Laser welds can be done right.
by liveforphysics
Nov 21 2018 5:42pm
Forum: Items for Sale - New
Topic: Accelerated Systems ASI BAC 4000 & BAC 8000 FOC BT Controllers
Replies: 62
Views: 3689

Re: Accelerated Systems ASI BAC 4000 & BAC 8000 FOC BT Controllers

22s explodes (at least on the 4000 model a few years ago at Joby).

21s can be tuned to be stable.
by liveforphysics
Nov 21 2018 5:39pm
Forum: E-Vehicles General Discussion
Topic: ‘When will you build an electric car that is only half as sexy as a Tesla?’, German minister says to automakers
Replies: 1
Views: 230

Re: ‘When will you build an electric car that is only half as sexy as a Tesla?’, German minister says to automakers

The automakers who don't already have meaningful EV experience are dead men walking. If they scrapped the entire benzene and/or nitric acid spraying production lines and product development programs, and put it all into making EVs, it would give them the best foundation for an attempt towards market...
by liveforphysics
Nov 19 2018 9:47pm
Forum: Motor Technology
Topic: Brushless motor efficiency
Replies: 14
Views: 545

Re: Brushless motor efficiency

Luke, if there is one thing I have learned from you it's that...if I have a big enough motor using enough amps, I won't be accelerating for long, I'll be up to cruise speed in a very short amount of time. Yep, you win burst power EV needs by finishing your brutal acceleration in a timely fashion pr...
by liveforphysics
Nov 19 2018 8:31pm
Forum: Motor Technology
Topic: Brushless motor efficiency
Replies: 14
Views: 545

Re: Brushless motor efficiency

This is running on my own controller so I scan write current limiting code also as a backup. I am hoping using a lookup table I will be able to get the throttle 'feel' how I want it. I can look at short bursts of even higher currents, but I am not sure if this will make more torque, or just warm th...
by liveforphysics
Nov 19 2018 5:02pm
Forum: Motor Technology
Topic: searching for legalisation documentation zero s 2014 driveline
Replies: 8
Views: 251

Re: searching for legalisation documentation zero s 2014 driveline

EMI is created by a complex relationship between vehicles chassis/frame, the wire routing, and the locations and mounting techniques. If you change how the wiring is ran and how the parts are mounted in the Zero, you will be greatly changing EMI performance. Fortunately for you, EMI only gets tested...
by liveforphysics
Nov 16 2018 2:05am
Forum: Motor Technology
Topic: Brushless motor efficiency
Replies: 14
Views: 545

Re: Brushless motor efficiency

It's core losses.

Many high performance motors overheat sitting on a bench no-load at full RPM, despite resistive copper heating from the windings. They may stay plenty cool in the application of spinning a propeller, or bursts of high power/rpm like an RC car.
by liveforphysics
Nov 14 2018 8:52am
Forum: E-Bike Non-hub Motor Drives
Topic: Sur-Ron - New Mid drive Bike
Replies: 2714
Views: 158440

Re: Sur-Ron - New Mid drive Bike

Congratulations my friend on getting real phase current! It awakes a beast in them with big phase current.