Recent content by cellmate

That's exactly what I've been trying to avoid with both the X and U patterns. I've been experimenting with my spot welder on some dead cells, and I've found that nickel-on-nickel welds are very weak. The same settings that can form a strong weld for nickel-on-cell creates very weak welds that...

I 3D printed a top and bottom plate for the whole battery. This is my first time 3D printing and I wanted to leave enough "meat" there for the 3D printer to be able to print it properly. Maybe I'll try it again with narrower spacing. I went with rectangular (vs staggered) layout to favor a...

All that being said, based on feedback in a different thread, I am considering a U shape now also. As previously stated, my main reason for the X was to avoid trying to weld the parallel connections over top of the series connections, since there isn't enough room on the positive terminal for...

dont know why you write .07% which is a tiny amount. doing the x on the rectangularly arranged cells would be 30% more strip needed and 30% more resistance. Yes, it is 30% more nickel and 30% more resistance. My calculations showed a 39% increase in losses (1.28 Watt vs 0.92 Watt). The 0.07%...

Thanks guys! Looks like I'll be going this way! I also discussed this in another thread where someone had somewhat related question, and there I calculated the additional loss from the longer runs of copper. Unless I screwed up the math, it was negligible: 0.07% less efficient for the whole...

Thanks serious_sam! I think I'm okay for quantity of nickel. I'm using 8mm x 0.2mm pure nickel, and the battery will drive an TSDZ2 which can only sustain 16-20 A continuously, so 8-10 A per strip. If I did the math right, it looks like the additional losses from the extra distance are pretty...

Here's a revised version with the polarities marked (for the "top" end of the cell that you can see in the diagram): For the bottom right group, I've shown the parallel path in blue, and the series path in magenta.

Thanks. Yes it is a slightly longer run. I'm going with fairly thick 0.2mm pure nickel, and expect the sustained load to be <= 10A per strip (20A for the battery), usually way under. I don't expect losses/heating in the nickel to be an issue. I'm more concerned about if there is any...

Hi all, I was wondering if there's any reason I should not weld a 2P battery pack in an "X" configuration, to avoid layering nickel strips and to reduce the amount of welds. I made a separate post here about it with more detail, but it has only gotten one response so I hoped I might get a bit...

I'm doing a 14s2p in a 7x4 configuration. My plan (and would love feedback here) is do this: Green are strips on top, red are strips on bottom, black dots are weld points. You can see at the split/fold (top of the picture), I intend to weld the inner two cells with a strip, and the outer...

Hi there, I'm building a 14s2p battery. I was wondering if there's any reason I couldn't weld the nickel strips in an X pattern, like shown in blue, rather than a typical rectangle as shown in green? The reason is, it would reduce the number of strips I need to weld (2 strips per quad, rather...

I just measured the wires: 1.8mm diameter, so about 13awg. Mine also jump around on each weld, and the tip gets uncomfortably hot after a few welds. I suppose I could look at upgrading this, but it's a bit annoying, as I specifically bought this unit since it was a well-liked ready-to-go unit...

Two pure copper wires, insulated with shrink wrap, rounded and sanded a bit to work well at a 45 degree angle. Here's a video of someone else using the welder from the other thread; I use it pretty much like he is doing. https://www.youtube.com/watch?v=voWpcxBbxoA Yeah, they're dead 0v cells...

Sorry, beyond the suggestion to clean and scuff the nickel, I didn't understand the reset of your suggestion. The welder is linked at the top of my original post.

Hi all, I have this spot welder: https://endless-sphere.com/forums/viewtopic.php?f=14&t=89076 I'm powering it with a 5000mah 50C sustained 100C burst 3S LiPo, welding 0.2mm pure nickel strips onto 18650s. According to the official documentation and what I've read in forums about this welder...