Search found 105 matches

by sleepy_tired
Sep 11 2020 11:24am
Forum: Motor Technology
Topic: Leaf / leafmotor / leafbike high efficiency 1500w motor
Replies: 1921
Views: 249751

Re: Leaf / leafmotor / leafbike high efficiency 1500w motor

I fear that when I cross that line will not have a bike anymore and everything will get big and heavy, look like some type of motorcycle. It's better to have a specialized bikes for different purposes then trying to have a do-everything bike. Trying to dream up a bike that goes miles at a 100 mph t...
by sleepy_tired
Sep 11 2020 11:04am
Forum: Motor Technology
Topic: Leaf / leafmotor / leafbike high efficiency 1500w motor
Replies: 1921
Views: 249751

Re: Leaf / leafmotor / leafbike high efficiency 1500w motor

There are plenty of good choices for running a reduction drive. The Astroflight motors that are available can peak over 95% efficiency, and can pack a lot of power in a small package. I would want something larger and more suitable for traction motor. Each stage of reduction represents a significan...
by sleepy_tired
Sep 10 2020 1:59pm
Forum: Motor Technology
Topic: Leaf / leafmotor / leafbike high efficiency 1500w motor
Replies: 1921
Views: 249751

Re: Leaf / leafmotor / leafbike high efficiency 1500w motor

If I was going to build a high speed bike I wouldn't look into using hub motors anymore. I love hub motors for ebikes and other slow moving vehicles, but it's likely that single speed reduction IPM motor of modern design would be much better. Even liquid cooling. No clutches or anything like that th...
by sleepy_tired
Sep 10 2020 11:39am
Forum: Motor Technology
Topic: Leaf / leafmotor / leafbike high efficiency 1500w motor
Replies: 1921
Views: 249751

Re: Leaf / leafmotor / leafbike high efficiency 1500w motor

I'd very much like to build up a full-suspension electric velomobile geared to top out at 80-100+ mph and do 0-60 mph in under 6 seconds, and such a 3-motored setup when given the proper selection of motor wind, right battery pack and controller settings would be powerful enough to do it! But if th...
by sleepy_tired
Sep 10 2020 10:49am
Forum: General Discussion
Topic: Tips on using lifestyle to improve immune response and survive any virus
Replies: 11
Views: 699

Re: Tips on using lifestyle to improve immune response and survive any virus

Food and lifestyle choices are the #1 most important thing when it comes to avoiding damage from covid-19. Far more important then any doctor or hospital or vaccine or anything like that. In the USA we have nearly 180,000 people died from covid out of 330,000,000 people. Comorbidity play a huge rule...
by sleepy_tired
Sep 10 2020 9:40am
Forum: Motor Technology
Topic: Understanding QS205 efficiency and power
Replies: 20
Views: 1248

Re: Understanding QS205 efficiency and power

Field Wakening (FW) is an extension of speed/RPM not torque. Field weakening increases torque in order to get those higher speeds/rpms. That's the point. DC motors lose the ability to produce torque the faster they spin. When you reach top speed on your bicycle the torque output of the motor is bal...
by sleepy_tired
Jan 30 2020 12:25pm
Forum: Motor Technology
Topic: Same debate again, motor windings!
Replies: 96
Views: 6645

Re: Same debate again, motor windings!

I think I remember the post in question and Justin was making the point that a lot of the "cogging torque" people feel is just trying to overcome magnet repulsion and attraction. As you push through the magnet resistance and get to the 'other side' then the magnets push away with similar f...
by sleepy_tired
Nov 27 2019 3:34pm
Forum: E-Vehicles General Discussion
Topic: Motortrend article with tons of info about Tesla’s Cybertruck
Replies: 111
Views: 10755

Re: Motertrend article with tons of info about Tesla’s Cybertruck

Love the design, features, and performance.

Hate that it's rolling spyware.

So I won't be buying it, but it's still very cool. Modern cars all look like half-used bars of soap. SUVs look like two used bars of soap smashed together. Look at a big parking lot sometime. It's depressing.
by sleepy_tired
Nov 21 2019 10:56am
Forum: Motor Technology
Topic: QS 3000w midmotor
Replies: 609
Views: 82547

Re: QS 3000w midmotor

All I know about flux weakening is that experiences with SPM motors, especially DD hub motors, do not translate to IPM motors. Totally different beasts. Also that flux weakening may be necessary across the entire RPM range of a IPM to unlock the best performance. The figures from QS are probably tru...
by sleepy_tired
Nov 20 2019 3:52pm
Forum: E-Vehicles General Discussion
Topic: What about Q70 motor hub?
Replies: 3
Views: 1893

Re: What about Q70 motor hub?

They are not going to be nearly as nice as the newer small hub motors from Bafang, like the G310. Less efficient, but also lower cost. You can probably make up the difference by spending the money you save on higher capacity batteries. As long as you keep the motor within specs it shouldn't make a b...
by sleepy_tired
Nov 20 2019 3:33pm
Forum: EBike Non-hub Motor Drives
Topic: higher or lower kv
Replies: 115
Views: 14746

Re: higher or lower kv

If you're trying to make the most torque from a given controller with a fixed amp limit, or from a given battery with a limited current capability, high count motor winding is how you do that. You trade off motor RPM for more torque. With a the same limit on voltage and amperage you get less torque...
by sleepy_tired
Nov 19 2019 3:27pm
Forum: EBike General Discussion
Topic: Convert 2 Classic MTBs to eBikes
Replies: 14
Views: 1564

Re: Convert 2 Classic MTBs to eBikes

1) Are these classic cromoly frames a good starting point? I know from experience that those frames are very strong and lively frames, even if a bit on the heavy side, so I think they are a good place to start. They are a good start. What is especially hilarious is that the new hotness is 'gravel b...
by sleepy_tired
Nov 19 2019 2:46pm
Forum: EBike General Discussion
Topic: singlespeed rear hub motor for 120mm spacing?
Replies: 47
Views: 5197

Re: singlespeed rear hub motor for 120mm spacing?

If the frame is aluminum then resizing to 135mm is ill-advised.

but if it's steel, go for it.
by sleepy_tired
Nov 15 2019 4:10am
Forum: EBike General Discussion
Topic: Preventing BBSHD Removal
Replies: 25
Views: 2309

Re: Preventing BBSHD Removal

Most of the time glues can be softened up with some heat.
by sleepy_tired
Nov 15 2019 4:09am
Forum: EBike General Discussion
Topic: singlespeed rear hub motor for 120mm spacing?
Replies: 47
Views: 5197

Re: singlespeed rear hub motor for 120mm spacing?

https://bmsbattery.com/motor/631-16312-q100h-36v350w-rear-driving-ebike-hub-motor-ebike-kit.html I _think_ that should work. It has a spacer that can be removed. Remove the spacer, grind it down if you need to. Don't own the motor and don't know for 100% sure. By default it's configured for 135mm dr...
by sleepy_tired
Nov 14 2019 11:21pm
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 117
Views: 11814

Re: What battery to choose after your last one burned your house.

Even commercial ebike batteries don't seem to have it. Em3ev fuses their cells in most of their batteries. They also fuse the balance lines. it also does not serve any purpose. each cell has a PTC disk in it that will pop if a cell goes postal and reduce damage to cells next to it. the people that ...
by sleepy_tired
Nov 14 2019 11:00pm
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 117
Views: 11814

Re: What battery to choose after your last one burned your house.

You don't need a mini-heater. Just wire in a incandescent light bulb. 60 watts or something like that. 60 watts of heat is plenty to keep something warmer then ambient in the winter. and how would you cram a light bulb into a battery? and why would you waste energy on creating light when you need h...
by sleepy_tired
Nov 11 2019 3:34pm
Forum: EBike General Discussion
Topic: Why not comfort bikes?
Replies: 87
Views: 6750

Re: Why not comfort bikes?

There are two types of brass-style processes. Brazing and braze welding. They are very close. Brazing depends on very small joints that are very clean. The brass will get sucked into the joint through capillary function. This is what people use for welding custom steel bikes with lugs. The tubing is...
by sleepy_tired
Nov 10 2019 3:19am
Forum: Battery Technology
Topic: What battery to choose after your last one burned your house.
Replies: 117
Views: 11814

Re: What battery to choose after your last one burned your house.

You don't need a mini-heater.

Just wire in a incandescent light bulb. 60 watts or something like that. 60 watts of heat is plenty to keep something warmer then ambient in the winter.
by sleepy_tired
Nov 10 2019 12:57am
Forum: E-Scooter and Motorcycle General Discussion
Topic: KYMCO RevoNEX
Replies: 6
Views: 1077

Re: KYMCO RevoNEX

I think it's multi-faceted. Lack of competition in the space, lack of experience explains the multi-speed gearbox. Some of the engineers are new to electric motors and don't understand all of the trade-offs. Market research might have shown that customers don't have experience with electric motors a...
by sleepy_tired
Nov 08 2019 7:06pm
Forum: Battery Technology
Topic: Super Capacitors for "Burst Mode"?
Replies: 27
Views: 1698

Re: Super Capacitors for "Burst Mode"?

It actually makes sense for car stereos. Just think of it like this, a car audio system's load can rapidly fluctuate from 10-100%, based on when a bass drum is hitting, or not. Reproducing low frequencies takes a lot of electricity, and the low frequency hits are intermittent in most music. So you ...
by sleepy_tired
Nov 08 2019 2:28pm
Forum: EBike General Discussion
Topic: New hubs with magnet orientations like Tesla Raven powertrain?
Replies: 3
Views: 453

Re: New hubs with magnet orientations like Tesla Raven powertrain?

This is my limited understanding: Telsa model 3, from what I can tell, is a IPM motor. The magnets it's using are a series of smaller magnets glued together to create a halbach array. The way these motors can be thought of is a combination of permanent magnet 'PMAC' or 'BLDC' at slower speeds and a ...
by sleepy_tired
Nov 08 2019 1:28pm
Forum: Battery Technology
Topic: Super Capacitors for "Burst Mode"?
Replies: 27
Views: 1698

Re: Super Capacitors for "Burst Mode"?

If you combine capacitors with batteries what will happen is that the capacitors will increase the load on the battery, not reduce it. Imagine you accelerate hard and notice that the battery cannot keep up due to the high voltage drop. So you add a capacitor bank to 'fix' it. Now you accelerate hard...
by sleepy_tired
Oct 31 2019 10:55pm
Forum: EBike General Discussion
Topic: Hub motor industry dying?
Replies: 270
Views: 18401

Re: Hub motor industry dying?

Remember that cogging is a two-way street. It's like riding up and down tiny hills. The magnets push you along they load up, like a spring. You lose some energy to heating up the motor, but it's not very much. Also reduced cogging is one of the reasons to buy higher quality DD motors. So while you g...
by sleepy_tired
Oct 29 2019 11:38pm
Forum: EBike Technical
Topic: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)
Replies: 2277
Views: 349433

Re: 19" Motorcycle Wheels vs 26" Bicycle Wheels (rim and tires)

The old fashioned way to balance car tires was to use a machine that just let the tire teeter-totter then you'd add weights to make it even. You can still pick up a balancing tool from harbor freight that uses a bubble indicator. Not as good as a real balancing machine, but it'll get you in the righ...