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by spinningmagnets
Jun 17 2019 4:15pm
Forum: Battery Technology
Topic: Automotive spot welder as battery welder?
Replies: 5
Views: 103

Blah, blah, blah...

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 asid... 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: 197

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: 204

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: 741

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: 369

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: 741

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: 280

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: 82552

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: 283

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: 388

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: 283

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: 219

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: 37614

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: 11334

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: 184

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: 184

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: 184

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: 576

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: 32366

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: 155

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...
by spinningmagnets
Jun 01 2019 4:51pm
Forum: Battery Technology
Topic: Mapping current through high-amp bus materials (spot welding)
Replies: 2
Views: 155

Re: Mapping current flow through high-current buse materials

Here is a pic of "dimpled" nickel buses. I don't know if they have a copper core. If we use dimples on our DIY buses, then the coppers high conductivity doesn't matter, because the spot-welding current direction only has one contact point to flow through. SpotWeldingCopper7.png SpotWeldingCopper6.pn...
by spinningmagnets
Jun 01 2019 4:50pm
Forum: Battery Technology
Topic: Mapping current through high-amp bus materials (spot welding)
Replies: 2
Views: 155

Mapping current through high-amp bus materials (spot welding)

I am now convinced more than ever that the positive end of an 18650 / 21700 cell can take quite a bit of abuse. However, the negative end is sensitive to heat, with the most common culprit being a high-watt soldering iron. I accept that the BEST method is ultrasonic wire-bonding (Tesla, Alta, LunaWo...
by spinningmagnets
Jun 01 2019 1:09pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 213
Views: 32366

Re: Spot Welding Copper Strips to 18650 Battery Cells

I'm looking forward to retirement, because then I would have had the time to perform dozens of experiments that have been on the back burner for a couple years. Making a sandwich of copper/nickel is affordable and easily done with existing supply-line materials. DIY nickel-plated copper? what thickn...
by spinningmagnets
May 31 2019 11:33pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 213
Views: 32366

Re: Spot Welding Copper Strips to 18650 Battery Cells

Don't know if this is legit, but it appears intriguing. Earlier in this youtube, he shows that he has a FET bundle (75 FETs) as the on/off switch. Probably way too many, but if you have a pile laying around, why not? The 12V timer is powered by three 18650 cells in 3S / 1P (the red cells in the back...