Not nessesary, in fact, don’t do this. If the cells arrive at different voltages you should be concerned. They be should be within 0.001v. This makes it less safe to build as any short will now be stronger.
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Use this. Make sure there are no sharp corners and that anything remotely sharp has fishpaper under it (whether it’s an insulator ring or just a piece of fishpaper.)
I don’t have anything that tests cells that low, my nitecore d4 showed all cells going in at within 0.01v of eachother. Once I solder together the p-groups I can discharge each group to an appropriate level.
I charged them all to 4.2 as that’s what my bay charger automatically stops at and I wanted a way to make sure they were all as even as possible.
There is quite literally a battery builders thread for this type of post mate…
Zero reason you should ever need to do this. And if anything this is a bad idea because you’ve now raised the potential for hazard when handling the pack. Touching the ends of a fully charged 12S pack will be noticeable. If you haven’t finished the build, or were to ship this pack you now need discharge back down to storage.
Generally scissors work, but you’ll wreck the scissors over time so don’t use your moms favorite or anything. An upgrade would be non serrated shears.
If the cells were purchased new from a reputable dealer, then that’s not a concern. They’re shipped at storage voltage and in most cases, should be built into a pack in the same state.
Oh well, I’ll just have to discharge them and lose half a cycle. Any reccomendations on discharging back to storage voltage? I’ve read about using a light bulb.
In the future I plan to acquire an oscilloscope, an variable load and a CC/CV power supply, but currently I’m just trying to gather and master my necessities for assembling packs.
Better tools will come as I gain experience.
I understand that pre-charging the cells makes this more dangerous to work with, but if I’m worried about that then the pack isn’t safe enough. Nothing should short or spark if this is assembled well.
Anyway, after a dozen posts about that, back to useful content.
Anyone have suggestions on what shape I should cut my nickel? I’ll be doing wiring on top as I have the enclosure space to do so.