I'm wondering how practical it would be to drill and tap terminals to add posts to batteries like this: https://batteryhookup.com/products/2x-sunwoda-lf314-314ah-lfp-prismatic-cells-grade-a-qualified-rohs-certified-ultra-long-life-10-000-cycles
The description says that you can only drill 5mm at most. Anybody do something like this before? I do have a shitty Harbor Freight drill press and couple hand tap wrenches.
6 Comments
Onomatopoeia@lemmy.cafe · 7 pts · 95d
5mm is tiny
I'd sooner invest in the spot welding tools.
cmnybo@discuss.tchncs.de · 6 pts · 95d
It can be done, but I would suggest doing it outside to be safe. Set the depth stop on your drill press so you can't go too deep.
You will need a normal tap to get started and a bottoming tap to finish threading the hole all the way to the bottom. 5mm is not a lot of thread to work with in soft aluminum. Those terminals are intended to have bus bars laser welded to them.
NaibofTabr@infosec.pub · 5 pts · 95d
You can get handheld spot welders intended specifically for battery terminals for US$30-50. Spot welding is a lot less likely to damage the cell or risk puncturing it. Here's an example:
https://ebay.us/m/adsJwa
sobchak@programming.dev · 3 pts · 95d
I don't think those would work for these large batteries. I have one that I use for small cells though (i.e. 18650/21700).
NaibofTabr@infosec.pub · 1 pts · 95d
OK, I'm no expert but it says this at the end of that product listing:
Are you saying they need a heavier gauge bus bar for the current, something too thick for a small spot welder? Would you MIG/TIG weld a battery contact?
sobchak@programming.dev · 4 pts · 95d
Yeah, these are 0.5C cells, meaning they can safely discharge 157A (I would be using them for offgrid solar), so those little nickle strips would melt. I think TiG welding these would be extremely dangerous and produce too much heat (and I've never TiG welded before; just badly MiG welded a couple times). By "welding" in the description they mean commercial laser welders.