Quick update, it's been almost 90 days since I ordered these packs from Xuba. Received a note from them this week stating the cargo ship had an "accident" and will be in Mexico for repairs until sometime in March.
Bleh.
Fascinating study that isn't behind a pay wall. Thanks for sharing. Now if I could just afford (and power) a 4 kilowatt industrial laser. The benefits of laser welding outweigh the downside if done properly (in particular for high corrosion environments like high humidity coastal environments). But the key is the phrase "done properly". Judging by the quality of the one example that I have seen from Xuba, that is not likely.Yeah, I was curious about how laser welding works, and stumbled across this:
https://www.mdpi.com/2313-0105/6/3/47
Those appear to be "lap welds". I won't pretend that I have read the whole document yet, but it looks like it was just recently published.
I think the key here, since these batteries will be mounted inside a travel trailer, is keeping the cells from jiggling independently of one another. Too much of that nonsense, and either the weld or the cell terminal itself will just break loose. If they are gonna jiggle, they need to jiggle as a whole pack.
If I compress the packs slightly, and then mount them with some type of vibration absorption foam between the packs and the floor of the trailer, it should be enough.
I don't plan on any off-roading with the trailer obviously, but washboard roads are the worst and I have seen the havoc they can wreak on the inside of a travel trailer.
Fascinating study that isn't behind a pay wall. Thanks for sharing. Now if I could just afford (and power) a 4 kilowatt industrial laser. The benefits of laser welding outweigh the downside if done properly (in particular for high corrosion environments like high humidity coastal environments). But the key is the phrase "done properly". Judging by the quality of the one example that I have seen from Xuba, that is not likely.
The Long Wei supplied alligator leads are much better than most.Top balance is done on Pack 1.
Pack 1 Voltages (after 24hrs)
Thanks to LuthJ for the top balance procedure, worked flawlessly.
- 3.37
- 3.43
- 3.42
- 3.49
Just for kicks, I did a little test. I made a couple sets of my own test leads, and I did a little head-to-head with the banana plugs that came with the power supply.
I made a set of leads with rings on both ends, but I also wanted to try these 10a rated pure copper alligator clips:
View attachment 41496
So for the following test, the same cell is being charged, and same PS settings for both tests:
Factory leads (alligator clips)
View attachment 41497
Homemade leads (12AWG wire, ring connector on the PS, copper alligator clips)
View attachment 41498
It’s interesting to me that I can get pretty much full 10amps from the PS just using copper alligator clips clamped onto the battery terminals (well, in my case….bus bars). It says to me that the surface area of the attachment to the battery is not critical to getting full current.
What is it that sucks about the factory leads then? The wire? The stainless alligator clips? The connection to the PS?
I'm hoping you ordered 170AH packs?Top balance is done on Pack 2.
Pack 2 Voltages (after 24hrs)
Also completed capacity test on Pack 1, it was over 178ah (!!) when I stopped the test at 12.2v before it hit the BMS low voltage cutoff. Possible I could have pushed it to 180ah if I let it go all the way to 12v.....but I didn't really see any point in that.
- 3.34
- 3.43
- 3.38
- 3.38
176ahI'm hoping you ordered 170AH packs?
I did not, I don't have a tester that can do that unfortunately.Good stuff. Nice looking setup. Did you by chance test internal resistances out of curiousity?