with barley paper (fish paper) stickers to prevent nickel shorting
spot welded with 4 stripes of nickel
6 welds per point of contact (i.e. 12 per cell)
stuck into two layers heat shrink with thick polypropylene strips on the sides to exclude the possibility of nickel rubbing through the insulation and shorting
neoprene strips as padding
with 10 AWG wires on each side
welded by a professional welding service
Measured by how much use li-ion batteries usually go through, I’d say these are almost new. I’ve charged the entire pack of 12s4p maybe 10 times in total, always with a BMS, so always balanced.
Price (USD): EUR 25 each (or what you offer, if it agrees with my not very high expectations)
Im going to go out on a limb here and say these aren’t welded by a professional spot welding company as the top layer of nickel is missing a corner from a weld blow-out and whats remaining of the corner is incredibly sharp and positioned off-center from the positive battery tab…
It is not missingw a corner there - it only looks like it on the picture. I had the same doubt brought up in the previous thread but checked and it’l wasn’t the case. The packs were made by a professional.
I would agree, the individual may have been “professional” but they aren’t really up to our standards. Our professionals here round their nickel corners and you’d see a bit higher build quality overall
Also 25r cells are kinda old now, only good for weak chinese escs with low amp draw imo
I agree with most of the stuff said above.
Judging them as DIY packs, other than a couple cut corners (such as the corners not being cut ) they are at least “okay”. Nothing spectacular, but not an immediate fire hazard.
I would be a little wary of trying to pull a lot of current from them, because the main high-current connection is on one side rather than in the middle, which would mean asymmetrical current and heating in the nickel.
The fact that they used very narrow nickel and then tried to compensate by doubling up also makes me a little wary.
These would probably be fine in a scooter or light ebike, but not in an esk8 IMO.
It was 3 or 4y ago, I haven’t got the email exchange with the company and don’t remember the name, but they were building battery packs for electrical bikes.
) they are at least “okay”. Nothing spectacular, but not an immediate fire hazard.