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by spinningmagnets
Jun 18 2019 8:40pm
Forum: Battery Technology
Topic: 18650 Insulator Rings - Redundant?
Replies: 8
Views: 122

Re: 18650 Insulator Rings - Redundant?

Although 18650's are frequently used in ebike battery packs, they were designed for cordless tools and laptop computers. If you do not add the fiber washers, it is likely that your pack will be fine. However, even though the possibility of a cell developing a short is very rare, it does sometimes ha...
by spinningmagnets
Jun 18 2019 8:18pm
Forum: Battery Technology
Topic: 18650 Insulator Rings - Redundant?
Replies: 8
Views: 122

Re: 18650 Insulator Rings - Redundant?

The fiber washers do not shrivel and shrink when they get hot.

Also, sometimes the can is exposed due to vibration or a crash. These fiber washers are cheap.
by spinningmagnets
Jun 18 2019 10:43am
Forum: E-Bike Reviews & Testing
Topic: Luna 52v Wolf Batterty / Hobby king turnigy review.
Replies: 9
Views: 554

Re: Luna 52v Wolf Batterty / Hobby king turnigy review.

When I found out that the EGO line used 14S lithium, it dawned on me that an old ebike battery pack with only half of its range left in it would be replaced by me to get back the full range. But...what to do with the old one? A 24-Ah pack with only maybe 10-Ah left in it would still have more range ...
by spinningmagnets
Jun 18 2019 10:35am
Forum: E-Bike Technical
Topic: DIY 0-5k throttle
Replies: 11
Views: 191

Re: DIY 0-5k throttle

Fechter published a circuit a few years ago

"Throttle Smoother 3.0 - Linear Ramp Circuit"
viewtopic.php?t=47843#p708583
by spinningmagnets
Jun 17 2019 4:15pm
Forum: Battery Technology
Topic: Automotive spot welder as battery welder?
Replies: 7
Views: 170

Abc

In the interests of full disclosure, I was once a dealer for the kWeld for about a year. However, I do not profit form any particular model at the moment. That ebeing said... Using a cheap and available car starter solenoid means that the timing will be very crude. If you use semi-conductors as the ...
by spinningmagnets
Jun 17 2019 7:37am
Forum: E-Bike Build Threads / Photos & Video
Topic: What to do with a Free Sondors?
Replies: 12
Views: 233

Re: What to do with a Free Sondors?

Continue to discuss ideas here, but also join the Sondors Facebook group. Rather than change the existing motor, if it was me.. I would add an identical motor to the front with it's own controller for 2WD, and double the stock power. Maybe put the stock controller on front, and the upgraded controll...
by spinningmagnets
Jun 12 2019 9:11pm
Forum: Motor Technology
Topic: RC ESCs in a real size motorbike? How stupid would that be?
Replies: 7
Views: 215

Re: RC ESCs in a real size motorbike? How stupid would that be?

The open-source Vedder-ESC (VESC) has been a huge improvement over past ESCs. It uses Field oriented Control (FOC) and that requires a shunt for each motor phase (three shunts). As far as the physical size, the Adaptto and Phaserunner use very efficient FETs instead of "affordable" FETs, so they wer...
by spinningmagnets
Jun 10 2019 7:39pm
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 765

Re: Which cell for long lasting battery

Its been a while since I researched the termination voltage where the BMS performs the balancing. I know cell-balancing can be done at 4.0V-4.1V with RC chargers on a pack with no BMS.
by spinningmagnets
Jun 10 2019 2:47pm
Forum: E-Bike General Discussion
Topic: old motors inefficient?
Replies: 12
Views: 381

Re: old motors inefficient?

The venerable 40X series should not degrade a measurable amount over time. If you overheat the magnets, the classic symptom is less power and a higher top speed.

Shorter range is the classic symptom of an older battery pack that has lost some of its capacity.
by spinningmagnets
Jun 10 2019 12:42pm
Forum: Battery Technology
Topic: Which cell for long lasting battery
Replies: 32
Views: 765

Re: Which cell for long lasting battery

For some reason, the factory specs on cells continue to list 4.2V as the max charge per cell. Although lithium cells will work at 4.2V per cell, their life can be roughly doubled if you only charge to 4.1V per cell..and 4.0V is even better (going down to 3.9V per cell provides no benefit). It is use...
by spinningmagnets
Jun 10 2019 8:51am
Forum: Battery Technology
Topic: Need Urgent Help Finding a Specific Design of Nickel Strip
Replies: 7
Views: 296

Re: Need Urgent Help Finding a Specific Design of Nickel Strip

When you buy an order of bus material that ends up being nickel-plated steel, be aware it is still useful for the parallel connections. Just a thought...
by spinningmagnets
Jun 10 2019 8:32am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 722
Views: 82738

Re: kWeld - "Next level" DIY battery spot welder

Compoudbike, would you please post a paragraph that you feel would adequately explain this? Doing so would help kWeld upgrade their instruction manual for new users.
by spinningmagnets
Jun 09 2019 9:50am
Forum: Battery Technology
Topic: Adhesive-backed copper tape ampacity
Replies: 10
Views: 291

Re: Adhesive backed copper tape ampacity

I'm now thinking that this product might actually be useful for making parallel connections in a P-string, but...I wouldn't even bother to experiment using this for series current (even at only 10A peaks per cell)...just my humble opinion...
by spinningmagnets
Jun 09 2019 7:34am
Forum: Alternative Energy
Topic: Inverter recommendations, 48V sine wave, no grid tie
Replies: 14
Views: 392

Re: Inverter recommendations, 48V sine wave, no grid tie

That is great advice, Doc. I haven't mentioned that I already purchased a very large 48V UPS that is verified to work with 14S ebike packs up to 58V, It originally used four lead-acid batteries, and when the y wear out, the company will not let the customer replace the batteries (which is a very eas...
by spinningmagnets
Jun 09 2019 7:09am
Forum: Battery Technology
Topic: Adhesive-backed copper tape ampacity
Replies: 10
Views: 291

Re: Adhesive backed copper tape ampacity

I remember seeing a similar product and the specific product that I saw was intended to be used as speaker-wire. It could be attached to a wall and either painted over or covered by wall paper (or covered by kick-board trim). By being very thin and flat, it would be almost invisible without needing ...
by spinningmagnets
Jun 07 2019 10:41am
Forum: Battery Technology
Topic: Battery pack casing options
Replies: 7
Views: 228

Re: Battery pack casing options

You might go to Google images and search "Pelican case". The Chinese tool store "Harbor Freight" sells a similar product under the "Apache" brand that costs a lot less. I believe they have three sizes available...
by spinningmagnets
Jun 06 2019 5:44pm
Forum: Battery Technology
Topic: BOSS LEVEL CUSTOM SPOT WELDER
Replies: 435
Views: 37706

Re: BOSS LEVEL CUSTOM SPOT WELDER

What thickness of copper sheet are you using? What size and N-rating of magnet are you using? (link?)
by spinningmagnets
Jun 06 2019 11:49am
Forum: E-Bike General Discussion
Topic: EM3ev, setting the record straight on a few things
Replies: 89
Views: 11363

Re: EM3ev, setting the record straight on a few things

Yes, mentioning your country and city is helpful to detail the options.
by spinningmagnets
Jun 04 2019 7:30pm
Forum: E-Bike Technical
Topic: Proposal for soldering onto the negative end of 18650s
Replies: 4
Views: 192

Re: Proposal for soldering onto the negative end of 18650s

I know nickel-plated copper wire exists, and the cans on 18650's are nickel-plated steel. Nickel-to-nickel...I wonder if it would work?...
by spinningmagnets
Jun 04 2019 6:18pm
Forum: E-Bike Technical
Topic: Proposal for soldering onto the negative end of 18650s
Replies: 4
Views: 192

Re: Proposal for soldering onto the negative end of 18650s

I've never heard of cold-welding before, that is interesting. I am convinced that the "best" process is ultrasonic wire-bonding like Tesla and Luna Wolf, however...my brief investigation into what it would take to DIY an ultrasonic device looks like it would still be hugely expensive. This means tha...
by spinningmagnets
Jun 03 2019 9:08pm
Forum: E-Bike Technical
Topic: Proposal for soldering onto the negative end of 18650s
Replies: 4
Views: 192

Proposal for soldering onto the negative end of 18650s

The positive nipple of an 18650 / 21700 is very robust and can be reliably spot-welded or even soldered. However, the negative end is sensitive to heat. I know that billions of cells have been spot-welded by industry, but of course they are done by very expensive machines that provide very precise a...
by spinningmagnets
Jun 03 2019 5:51pm
Forum: E-Bike General Discussion
Topic: Ok, I bent the new rim... Looking for a stronger rim.
Replies: 10
Views: 578

Re: Ok, I bent the new rim... Looking for a stronger rim.

20-inch bicycle rim is the same diameter as a 16-inch moped rim...maybe an option.
by spinningmagnets
Jun 02 2019 12:27pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 213
Views: 32450

Re: Spot Welding Copper Strips to 18650 Battery Cells

Here's a video about spot-welding aluminum, using this trick of making a steel sheetmetal sandwich with the aluminum in the center. Start at 1:11

https://youtu.be/gcgC3V3mkcw?t=71
by spinningmagnets
Jun 01 2019 6:52pm
Forum: Battery Technology
Topic: Mapping current through high-amp bus materials (spot welding)
Replies: 2
Views: 158

Re: Mapping current flow through high-current buse materials

Now, I have to wonder what the cost would be, of 8mm wide stainless steel ribbon @ 0.10mm-1.15mm thickness as the "cap" layer...

...since it would not hurt conductivity, and it would facilitate an easy spot-welding process for the DIY battery pack builder...