Search found 11261 matches

by spinningmagnets
May 11 2021 7:17am
Forum: EScooter/EMotorcycle Build Threads
Topic: Golf E-Caddy
Replies: 2
Views: 51

Re: Golf E-Caddy

Nicely done! If you try a similar project in the future, consider the option of EGO yard tool batteries. They are marketed as "56V", but they've been disassembled and thoroughly examined, and they are 14S, or what we might call 52V. As such they will operate equipment that labeled 48V, and...
by spinningmagnets
May 10 2021 11:35am
Forum: Battery Technology
Topic: Index of flat pouch cell connection methods
Replies: 5
Views: 126

Re: Index of flat pouch cell connection methods

That sounds like useful info, would you please post some pics?
by spinningmagnets
May 09 2021 9:03am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 529
Views: 87796

Re: Spot Welding Copper Strips to 18650 Battery Cells

The shells of 18650/21700 cells are typically a steel core with nickel-plating for corrosion resitance.
by spinningmagnets
May 09 2021 8:20am
Forum: Battery Technology
Topic: Index of flat pouch cell connection methods
Replies: 5
Views: 126

Re: Index of flat pouch cell connection methods

Reserved for future data and pics
by spinningmagnets
May 09 2021 7:17am
Forum: Battery Technology
Topic: Index of flat pouch cell connection methods
Replies: 5
Views: 126

Re: Index of flat pouch cell connection methods

A closer look at the Jonescg method A hole-punch jig for tabs that are too thick for a paper hole-puncher https://endless-sphere.com/forums/viewtopic.php?f=31&t=38252&start=375#p1198715 https://endless-sphere.com/forums/download/file.php?id=196558 https://endless-sphere.com/forums/download/f...
by spinningmagnets
May 09 2021 7:17am
Forum: Battery Technology
Topic: Index of flat pouch cell connection methods
Replies: 5
Views: 126

Re: Index of flat pouch cell connection methods

Zappy used a common method of having the tabs touch each other with nothing in-between them, then he folded a thick copper sheet section over the tabs and used three bolts and nuts to clamp the assembly. I'll look for a better pic, but here is an example: https://endless-sphere.com/forums/viewtopic....
by spinningmagnets
May 09 2021 7:16am
Forum: Battery Technology
Topic: Index of flat pouch cell connection methods
Replies: 5
Views: 126

Index of flat pouch cell connection methods

There doesn't seem to be a definitive DIY solution to connecting the tabs on pouch cells, but quite a few ideas. I come across variations when I read about a pack build, so I'd like to collect the types here as a reference and a place of discussion. Today I just found out about the "Termifoil&q...
by spinningmagnets
May 08 2021 9:46am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 529
Views: 87796

Re: Spot Welding Copper Strips to 18650 Battery Cells

The area of concern is the negative end of the cell. As far as performance, 0.15mm thick copper has the same current-carrying capacity as 0.60mm thick nickel, with a much lower voltage-drop. (4:1 conductivity ratio between copper and nickel) The copper also acts as a heat-sink for the cell. The heat...
by spinningmagnets
May 08 2021 8:04am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 529
Views: 87796

Re: Spot Welding Copper Strips to 18650 Battery Cells

This is an awesome result! This is a new standard for high amp packs.
by spinningmagnets
May 07 2021 12:50pm
Forum: EBike General Discussion
Topic: DIY candidates
Replies: 11
Views: 258

Re: DIY candidates

I agree.
by spinningmagnets
May 06 2021 6:37pm
Forum: Battery Technology
Topic: Nickel welding strips - current capability ??
Replies: 17
Views: 7067

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: 126

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: 126

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: 126

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: 6
Views: 463

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: 763

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: 183

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: 183

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: 7
Views: 208

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: 763

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: 763

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: 7
Views: 243

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: 763

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...