This is the scooter I’m working on. It came with a 44V 1.7A charger.
It has a 1/2 amp trickle that I never used, and in hindsight, I should have.
Nice, the scooter looks like it’s built well. What’s the motor rated at?
350 watts at 36V
Oh whoops, you already told me that, sorry.
You can color me impressed! Nice work and nice score on the batteries! Love this forum. Thank you for sharing and taking pictures. I enjoyed reading this so far.
Hey, thanks for the kind words. I really like the friendly nature of the forum and how people share knowledge.
Today I soldered on for three more hours and got the pack almost finished. I just need to hook up the packs in series.
Here are some more pics of the three remaining packs:
I ran out of spacers so I printed out some more in red for Christmas. 
Cells came from Tesla? Maybe they are the 3600 Panasonic cells that were bought up….
Haha these were shipped to the club three years ago, so probably not. 
However, we will be getting about 2000-3000 A123 cells that another department is trying to get rid of. They have been torture tested in conditions similar to that of the moon. (vacuum, extreme heat and cold) and that’s why they are getting rid of them.
how much internal resistance and capacity do they have left?
The A123 cells? Not sure, we haven’t tested them yet. But the people who conducted the experiment said that they performed better after being tortured, but I guess they aren’t taking any chances.
I thought those were the cells you were using in the soldering pics above.
Performing better is very surprising though, one thing i have wondered about Model S cells is longevity, how much range would i have left (if i could afford one) after 15 years of use and maybe 100,000-200,000 miles on them
Oh the Tesla cells (most likely Panasonic 2900mAh) have just over 2,000mAh in them, which isn’t too impressive unfortunately. But it’s just one sample that I have tested, so I’m not sure how the rest will perform. I will perform a discharge cycle with a 300W electronic load in the club once the pack is finished and will report back.
For your intended application they should still have double or more the energy storage vs the original lead acid battery
Hopefully that is indeed the case. The SLA had absolutely no life it; it has ridiculous amounts of internal resistance even after he attempted recovery. I might just finish up the pack tonight after I get some dinner.
I’ve been contacted about the safety of soldiering to the bottom of the cells directly and whether it is a good idea to post photos of it. As expected, I am not saying that what I do is without any risk. It’s a risk that I’m willing to take because its overall outcome is positive to me as well as being a valuable learning experience.
That being said, my apologies for not clarifying the soldering process. It only takes 2-3 seconds to put a solder blob on the bottom of the cell as opposed to 1-2 for the top. It takes another 2-3 to attach a pre-tinned wire and in the end, the cell’s bottom is only 40C and the top is 30C right after I finish. The electrolyte in the cell will be hotter than 40C, and the performance will be degraded, but not by a measurable amount, and not enough to compromise the safety of the cells in my opinion.
If you’re daring enough to do this to your cells, no one is stopping you. However, as texaspyro has said, spot welding is a much better idea. 
Sorry for not getting around to finishing the work tonight, I’ll finish it up by tomorrow!
i hate lead acid, its deep cycle ability is abysmal, its service life is short, its energy density is low and its of course very toxic if not recycled properly
OK Bort, tell us how you really feel! 
I tend to agree. IMO it remains popular for one reason, INITIAL COST. Based on reviews on Amazon of SLA devices though that are not mains hooked up full time, such as backup power sources, makers of equipment using SLA batteries are not making customer friends. Such devices are not idiot proof and too many customers do not properly maintain them then are PO’d when the battery fails.
Yeah but pound for pound, dirt cheap compared to Li Ion or other high energy density options
Hence why they are still around, i would prefer a NiMH option, it would have more energy, last many more cycles and would cost less since it would still be going when your first lead acid dies and your buying another one
Perhaps its more accurate to say its cheapest upfront, not cheapest in the long term.
Try telling RC enthusiasts you cannot solder directly to your NiMh cells