Ct Scans of 1k Lithium-Ion Batteries Show Quality Risks in Inexpensive Cells

To summarize it myself, the battery is cylindrically wrapped sheets of anode/cathode material, and you want the top edge to have a straight line consistently having the anode layers (|) sticking out beyond the cathode layers ()

edit: Welp, the unicode I illustrated with got stripped out; so trying again with pipes

    anode
     cathode
      a a
       c c
    | | |
    ||||||

They specify 3800mAh minimum discharge at 0.2C for their 4000mAh cell. They don't show a discharge curve at 0.2C in their charts (would be 0.8A) but they do have a 1A discharge. When the 1A discharge curve reaches 3V, the energy discharged is right around 3800mAh.

Lumafield discharged at 0.2C, and they saw only 3055mAh.

Vapcell's site mostly shows high current discharge curves, where yes there is more capacity below 3V available, but with Li-ion at lower currents, the curve is very steep past 3V, not much more capacity left after that. And when you're discharging at high current you won't expect to get the full capacity, anyway.

I'll also take this time to point out lygte-info which is a treasure trove of battery tests.

[0] https://www.vapcelltech.com/h-pd-193.html

[1] https://www.lygte-info.dk/

Edited: Now that I looked at your product I have low expectations for an unbiased answer :-|

1. It says "Protocol implemented = no", but "Powers bike = yes", you can power a Bosch gen 2 motor without implementing the protocol, presumably this is referring to the CAN wire on the battery.

2. Your battery kit is 316 EUR without cells, and your BMS spare part is 99 EUR. If you can talk to Bosch motors then presumably this is where that special sauce is.

I for one might be interested in just something that serves to talk with the Bosch motor, and allows one to provide any arbitrary 36v source, do you or anyone else make/sell such a thing?

E.g. for range extending a cargo bike I'd find the cost/weight ratio of a beefy ~1220 Wh AGM 12v car battery coupled with a boost converter much more appealing than something that emulates the form factor of a ~500 Wh Bosch battery with Li-Ion 18650 cells, the range more than makes up for the extra weight.

A. https://infinite-battery.com/pages/compatibility-guide-of-th...

Batteries? Picture a fondue going wrong.

But those are (probably!) NiMH. No idea what brand of lions are in this cellphone, my laptop, my other laptop, my MicroPC, my other cellphone, etc.

How do you put that advice into action? When I'm in an electronics store, they don't typically let you look at the welds inside each battery bank. (And if they did, I have no idea what I'd be looking out for.)

They re-wrap other manufacturer's cells (but don't disclose who). I dislike this practice because, along with not knowing who makes the cell, you lose the original mfg batch codes, etc.

Sometimes they will simply rewrap something like a Samsung 50S. Those will be fine. But others ... who knows.

I work with (other) desktop microCT scanners and the longest scan we did took longer than 40 hours.

For that matter, jeez, how long does it take to just whip out a Dremel tool and take the battery apart for inspection? I must have misunderstood that comment.

For bulk storage LFP is a no-brainer, but there are still a lot of applications where you really want fast charging or need to handle big surges of current.

However, a LiPo cell that has entered Spicy Pillow mode (empty or not) can still theoretically burst, leaking or spraying toxic materials everywhere. So you were right to put it outside. Make sure you recycle it appropriately, so that it doesn't go into a landfill and poison the drinking water of our grandchildren someday.