Search found 11249 matches

by spinningmagnets
May 06 2021 6:37pm
Forum: Battery Technology
Topic: Nickel welding strips - current capability ??
Replies: 13
Views: 6898

Re: Nickel welding strips - current capability ??

Current flows in series in a battery pack. A strip that connects one cell to the other might only be one inch long, but...there are 15 of them in a 14S 52V pack. If the controller and motor are drawing 30A, then pass 30A at 52V through 15 inches of nickel strip to see if there is any voltage drop. N...
by spinningmagnets
May 06 2021 6:22pm
Forum: E-Vehicles General Discussion
Topic: Circumference and speed ?
Replies: 5
Views: 81

Re: Circumference and speed ?

180 ___ "X" 215 x 100 = For the two fractions to be equal, you can multiply the cross-located numbers and they will both equal the same number. Therefore...180 x 100 = 18,000 Then, 215 x "X" must equal 18,000 "X" equals 18,000 divided by 215 = 83.7 The smaller tire cir...
by spinningmagnets
May 06 2021 1:42pm
Forum: E-Vehicles General Discussion
Topic: Circumference and speed ?
Replies: 5
Views: 81

Re: Circumference and speed ?

After some thought, I agree.
by spinningmagnets
May 06 2021 6:44am
Forum: E-Vehicles General Discussion
Topic: Circumference and speed ?
Replies: 5
Views: 81

Re: Circumference and speed ?

Convert the tire circumference difference into a percentage, and that percentage will also be the change in speed, with RPM's being the same.
by spinningmagnets
May 05 2021 7:26pm
Forum: General Discussion
Topic: Historic "Deathbike" stolen in Oregon, $1500 reward
Replies: 5
Views: 269

Historic "Deathbike" stolen in Oregon, $1500 reward

Luke Workman, known as Live for Physics / LFP, was storing the "deathbike" in a new facility owned by Luna Cycle in Bend, Oregon.

$1500 reward for it's return.

Image
by spinningmagnets
May 05 2021 10:47am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

After some thought. I realized I dint actually have any experience with 250W hubs or mid-drives, so...please disregard anything I wrote previously.
by spinningmagnets
May 05 2021 10:41am
Forum: EBike Technical
Topic: Same kits, different results. Why?
Replies: 7
Views: 148

Re: Same kits, different results. Why?

Here is a link to the QS 205/50H hubmotor. The website page lists their three most popular kV's, the 3T, 4T, and 5T. The turn-count refers to the copper windings inside, so...they all look the same from the outside. https://www.qsmotor.com/product/3000w-bicycle-motor/ If you contact them, they actua...
by spinningmagnets
May 05 2021 10:13am
Forum: EBike Technical
Topic: Same kits, different results. Why?
Replies: 7
Views: 148

Re: Same kits, different results. Why?

If the battery voltage and tire diameter are the same, then the most likely reason is that he is using a high kV motor (low turn count), on a flat road. The air space around each stator tooth is a fixed size. The could can be made from many turns of thin wire, or a few turns of thick wire. This affe...
by spinningmagnets
May 04 2021 1:30pm
Forum: EBike General Discussion
Topic: building chopper e-bike
Replies: 6
Views: 136

Re: building chopper e-bike

A 16 inch moped rim will seat 20-inch bicycle tires. You might consider chrome spokes and a fat 20-inch tire for a chopper look.

Also contact dr chopper moser on Facebook. He may have the info you want.
by spinningmagnets
May 04 2021 10:02am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

The author has done a good job, but the article limits itself to 250W systems. This is understandable if the audience is from countries with a 250W power limit.   "...The conclusion is that the advantage of mid-drive motors is only noticeable in extreme situations, on steep slopes while the cyc...
by spinningmagnets
May 04 2021 9:54am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

The BBS02 is very common. It has been verified to work well with 52V x 20A = 1,040W For a "fair" comparison, we would have to use a 1,000W rated hubmotor. Which hubmotor would you like to use for a comparison? That being said, if we restrict ourselves to 250W, that a fairly important disti...
by spinningmagnets
May 04 2021 8:06am
Forum: EBike General Discussion
Topic: source for low capacity 52, 60, or 72v battery?
Replies: 5
Views: 136

Re: source for low capacity 52, 60, or 72v battery?

I'm a fan of the EGO yard tools. They are marketed as "56V", but they are definitely 14S (14 cells in series), which we commonly call 52V here. When fully charged, they are 58V. The mower uses either 5.0-Ah or 7.5-Ah. Both use high amp 2500-mAh Samsung cells. The casing may be a bit bulky ...
by spinningmagnets
May 04 2021 7:59am
Forum: EBike General Discussion
Topic: E-bike mid-drive motors hardly outperforms hub motors
Replies: 36
Views: 670

Re: E-bike mid-drive motors hardly outperforms hub motors

For a given performance level on flat ground: Mid drive is potentially lighter. A hubmotor is easier to install, and direct drive hubs have more power potential in high-power applications. Also, a hubmotor kit of similar power is typically more affordable. 'Xxxxxxxxxxxxxxxxxx Where a mid drive is wo...
by spinningmagnets
May 03 2021 9:52pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87247

Re: Spot Welding Copper Strips to 18650 Battery Cells

The thicker the copper, the harder it is to weld. Remember that the conductivity/resistance of 0.10mm copper is equal to 0.40mm nickel.
by spinningmagnets
May 03 2021 8:01pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 509
Views: 87247

Re: Spot Welding Copper Strips to 18650 Battery Cells

Copper/Nickel sandwich thread with settings and materials
viewtopic.php?f=14&t=108006
by spinningmagnets
May 02 2021 6:50am
Forum: EBike Non-hub Motor Drives
Topic: 3DE - 3D Printed Carbon Wrapped e-bike frame
Replies: 30
Views: 822

Re: 3DE - 3D Printed Carbon Wrapped e-bike frame

This should work fine. If the first version needs some upgrades in one spot or another, that's just the normal development process. A while back, there was a post about using abandoned foam. The builder used stiff hard foam insulation, carved it into the frame shape, inserted tubing for the head-tub...
by spinningmagnets
May 02 2021 6:21am
Forum: EScooters/EMotorcycles
Topic: Build
Replies: 19
Views: 369

Re: Build

What city are you in? Do you already have a frame?
by spinningmagnets
May 01 2021 4:44pm
Forum: EBike General Discussion
Topic: Where can I get the type of xt60 connectors that don't melt (fake/real?)
Replies: 8
Views: 227

Re: Where can I get the type of xt60 connectors that don't melt (fake/real?)

Even if they are counterfeits made from cheaper materials...if you melted them, I'd get thicker cables to act as a heat-sink, and a larger connector set, like the XT90's.
by spinningmagnets
May 01 2021 4:32pm
Forum: EBike Technical
Topic: Do some motors have more/less torque with the same power levels?
Replies: 22
Views: 488

Re: Do some motors have more/less torque with the same power levels?

It's possible to saturate the stator of a certain size of motor, and any additional power that you add will only be converted to waste heat. So...its possible that at a certain power level, a larger motor could make full use of the input watts, where a smaller motor would make less power when using ...
by spinningmagnets
Apr 29 2021 8:46am
Forum: Motor Technology
Topic: Electric motor - what voltage?
Replies: 31
Views: 912

Re: Electric motor - what voltage?

Brushless motors can tolerate a wide voltage range, more volts than we can afford. The limits of concern for the motor is heat. You would do well to add a temp sensor to the stator (they are tiny). This way you can explore the limits. At the very least, you will learn the temperature where your type...
by spinningmagnets
Apr 29 2021 7:52am
Forum: Bike Mechanical & Structural
Topic: Welding down a torque arm
Replies: 42
Views: 722

Re: Welding down a torque arm

Welding has been tried, I recall it worked well on steel frames.
by spinningmagnets
Apr 29 2021 6:59am
Forum: Bike Mechanical & Structural
Topic: Welding down a torque arm
Replies: 42
Views: 722

Re: Welding down a torque arm

I've seen some bonded with 3M's DP-420
by spinningmagnets
Apr 28 2021 10:28am
Forum: Alternative Energy
Topic: Hydrogen Drive - We Made the Battery Obsolete
Replies: 26
Views: 751

Re: Hydrogen Drive - We Made the Battery Obsolete

I'm sure a steady RPM would help efficiency, but I suspect the greatest benefit would be for emissions. During the VW diesel scandal, it was revealed that they lied about emissions in order to provide excellent mileage (*50 MPG+). When any combustion engine mixes fuel and air, a constant rpm can be ...
by spinningmagnets
Apr 28 2021 8:52am
Forum: Alternative Energy
Topic: Hydrogen Drive - We Made the Battery Obsolete
Replies: 26
Views: 751

Re: Hydrogen Drive - We Made the Battery Obsolete

I recall one experiment similar to the early Honda CVCC engines. The main cylinder has a fairly lean fuel/air ratio to provide exceptional milage, and a small pocket next to the spark plug had an air/fuel mix that was optimized for easy ignition. The similar experiment put a small amount of H2/O2 ne...
by spinningmagnets
Apr 28 2021 7:40am
Forum: Battery Technology
Topic: Spot Welder Electrodes Stick Baaad
Replies: 19
Views: 1143

Re: Spot Welder Electrodes Stick Baaad

If you are blowing holes in nickel ribbon, then the current is way too high. If the settings are the same as when you were getting perfect welds, then I suspect the machine is malfunctioning. The sudden nature of the change seems to agree that it's current setting is way off. Side note: in the futur...