Thousands. Enough for everybody. Prices are low right now, but I suspect these cells will be popular and I will probably raise them as we go.
2 Likes
They are tested as battery packs, charged and discharged as a pack then I just test the capacity of one-two cells from a pack to double check quality.
If you receive any bad cells I will replace them
I remember this pack. Itâs a jump bike battery pack. I found one a few months ago in SF TL area. I could not figure out how to use the built in bms. I have to take out the bms.
UhhhhâŚwrong.
This can be super dangerous. I just imagine a new builder spot welding these cells and not getting a full/solid connection all the way across the terminal. Short city.
Have you tried doing it? Do you have experience welding over old tabs, or soldering on top of old ones?
How is it short city exactly? Itâs hard for me to imagine how can you short it by welding or soldering on top of a single terminal.
I soldered dozens of packs with leftover tabs, the solder actually is confined to the leftover tab and doesnât go on the terminal, therefore not damaging the cell with the extra heat. All it takes is just a little bit of hammering on top of the tab and sanding it slightly.
Can anyone link me to a source where it says with full authority and peer reviewed research that soldering or welding on top of old welds and leftover tabs is way worse than doing it on clean surfaces?
Iâm basing my opinion on experience and experience of other certified electricians, I have heard otherwise only on forums like these from random people.
Yes and yes. It seemed very unstable so I took the time to remove the nickel and get a fully solid weld. Your blatant disregard for the opinions of trusted builders here is pretty ridiculous.
Yea i get it, save some money, but donât sell dreams of rainbows and blow jobsâŚits going to be alot of extra effort to make sure whatever pack being made with these is done safely and will last through the abuse we put on these machines.
This isnât a power wall. It gets abused and shaken around. I would want the most solid connection possible with nothing under it but battery.
2 Likes
I literally made dozens of packs for the boosted mod with these cells, the packs that are attached to the middle of a super flexy board and are bent several degrees. Hundreds of miles on them without any issues. Do the batteries that you had issues with because of the leftover nickel tabs were bendy and flexible? I donât think the packs that are made with these cells are usually bent at all, so the connection has absolutely no reason to be stressed by movement or friction, itâs purely for energy transfer. Which it does just fine with leftover tabs.
These guys. If youâre familiar with boosted, the middle is super bendy, probably the bendiest of them all. And you attach these packs right in the bendiest part - the middle.
So I made dozens of these for mods, and for my own boards. Hundreds of miles, not a single connectivity issue. All with leftover nickel.
I mean itâs only logical, the previous weld was strong enough, it shouldnât magically cause problems with connectivity just because it doesnât look clean.
1 Like
Iâm gonna do a side by side test with clean cells and with leftover nickel cells. Will spotweld and solder two clean ones and two with leftovers then will attach weights until it snaps and compare the results.
The prediction is that the cells with leftover nickel will fail faster under the weights? Thatâs how youâd test the theory that leftovers should be removed for a better joint, right?
1 Like
Not choosing a side here, some of the methods employed for battery packs here are over the top, some are very useful. ALl that aside, I would be very interested.
My application for these cells would be ebike so Im not as worried about vibrations and such
1 Like
If the left over nickel is nickel coated steel, and I would bet money it is, spot welding on top should work very well.
Cleaning up cells is a huge labor though, and also load testing would be prudent, and would take weeks.
Love these prices. @dog how low could prices be, and at what quantity?
1 Like
Iâm very flexible, depends on quantity. Give me a number and Iâll tell you
2 Likes
Mooches review for those interested
@Dog can you tell us if the BMS on the ebike was limiting to under 10A per cell?
3 Likes
Can you pull a few tabs nickel tabs to see how clean it is? Coated steel leaves lots of scraps on the cells.
BTW @dog I still havenât had the time to find out the shipping.
1 Like
So the packs come from a e-bike that has 300w motor AND itâs pedal assist, meaning it basically never had a surge in apm use since itâs a low drain application. I canât tell if bms regulated it or not, but just judging from the setup itself I can assume that the cells never had the opportunity to be drained at 10a
300W/30v = 10A (when drained or close to)
Seems to me like thereâs a decent chance they were overloaded. If they came of. A fleet of public Access bikes , we know they were abused. Not trying to dagger your sale thread buuut :
Used cells that even new are liable to damage. Nopitynope
1 Like
Yeah, me too. The welds are a PAIN to take off, so if my targeted and concentrated effort canât break the weld with ease, what makes the vibrations on a pretty much solid block of cells so effective at magically disrupting the connections?
Anyone have any links to support those claims by the way? Any comparison tests, blogs, articles, anything? I tried to look, all I could find is brief mentions by amateur DIY battery pack builders.
As soon as there is a solid source for those claims I will change my mind, so far itâs just anecdotal evidence and elitist opinions.
Donât mean to sound abrasive, I am a man of science and donât want to waste time on sugarcoated pleasantries. I am very much looking forward to change my mind if facts are presented.
1 Like
300w on a pedal assist bike, meaning itâs never at itâs peak power since it doesnât have a throttle.
Besides, I purchase the newer ones so the chances they were abused are low.
What is this math by the way? How did you came up with it?
300W/30v = 10A (when drained or close to)
Maybe not, but you sure started asking a lot and assuming even more after I declined your offer to trade for cells I wasnât interested in trading 
I can actually provide peer reviewed papers for this. Cycle stresses are way worse than single impact forces . Iâve got 3 hours of e/m lecture to procrastinate through so you know itâs coming now haha.
Fair point. I wasnât to worried about the reds being used. But since youâre only trading blues I wanted to do research and see if the blues would work. I do love the red blue dicotomy
100% mutual. Glad we wonât piss each other off. Just trying to determine if these cells are good. Donât get me wrong at $1 a cell Iâm really only doing it because I need to know of theyâll work for my application