home made 18650 pack problem

[liveforphysics]

I don't know, I bet the 10A quote is pretty accurate for a single tab.
The thread you linked is showing theoretical numbers, on tabs that are probably not the same size as yours. It's also calculating the maximum amps the tabs can handle, not the amps it takes to only heat and deform the plastic over time.
A simple fix for your pack would be to solder some copper strands across only the series connections. The parallel connections are not a worry, since they carry very low current.

That would be a perfect fix.

Remember, hit it with a hotter than hell powerful and tinned iron, and scratch the nickel free of it's oxide layer (which is mild) before applying the iron. You need to be fast, the whole operation only lasting a few seconds, and this way you can keep the cell cool and undamaged.

[ic3wall]

A simple fix for your pack would be to solder some copper strands across only the series connections. The parallel connections are not a worry, since they carry very low current.

That's a very good idea, I could also spot weld 2 nickel tabs on top of each other on series connections. That would probably be less efficient than copper, but still it would help..

[ElectroSurf3r]

Oh and for the duct tape, you don't really need to break it down to individual cells. I think if you could break it down into your parallel strings of 6 cells, and just get under the 2 sides of the positive tab with duct tape, that should create enough space to eliminate most of the risk. Not to mention it will protect the groups of 6 from each other.

[pwbset]

On the 18650 batteries the only thing positive is the small disc on top. If you were to remove even a little of the shrink wrap around the positive disc that's all the battery ground.

This used to happen to me all the time when I worked with used konions. Even the tiniest little rip or defect in the green covering and ZAP! As others mentioned just adding a little duct tape or whatever before you tab weld can save headaches later.

How are those cells by the way? I just got an e-newsletter from Milwaukee this morning touting their M18 FUEL tools and Redlithium batteries. I used to use the 26650 emolis in the old V28s and they were pretty decent for ebike use.

[ic3wall]

On the 18650 batteries the only thing positive is the small disc on top. If you were to remove even a little of the shrink wrap around the positive disc that's all the battery ground.

This used to happen to me all the time when I worked with used konions. Even the tiniest little rip or defect in the green covering and ZAP! As others mentioned just adding a little duct tape or whatever before you tab weld can save headaches later.

How are those cells by the way? I just got an e-newsletter from Milwaukee this morning touting their M18 FUEL tools and Redlithium batteries. I used to use the 26650 emolis in the old V28s and they were pretty decent for ebike use.

they are pretty good, 1.3Ah, max discharge rate is 15C

only bad thing is that they charge at 0.5C...

[FastDemise]

So roughly a 2 hour charge time is bad? I got a bulk charger is only able to charge at .25C

Not sure I saw it but do you have any numbers on what your peak/average current draw is on your bike?

[ic3wall]

I don't have any numbers yet because I didn't have the chance to do any long rides... I finished my setup in early January and it's winter here. Now, I'm limiting current to 20A since Justin (ebike) told me that my motor (9C) would probably overheat over 1000W.