I can't find any button top's in higher amperages at this time. I've got a bunch of Molicel 25am 18650's that are flat tops. I purchased some 8mm x 2mm magnets as spacers and so far no issues.
I feel like if solutions like this aren't widely used there's probably a good reason.
What are your thoughts?
They aren’t widely used because they aren’t safe. Magnets can slide in or out into the cell, causing short circuits.
I prefer using these adapters instead.
4x18650(fits the BLF Q8 series of lights)/3x21700:
https://www.aliexpress.com/item/1005003993682557.html
1x18650:
https://www.aliexpress.com/item/1005003318392595.html
1x 21700:
https://www.aliexpress.com/item/1005003318519001.html
1x 26650:
https://www.aliexpress.com/item/1005003031942340.html
They’re best used/reserved for cells in series and that also have dual springs (rather than a spring and a solid contact post like is popular lately on drivers), where they can serve as a button between the cells but the batteries aren’t rattling around. If used on the positive end where it contacts the driver, the risk of it slipping and causing a direct short on the cell is not insignificant. The adapters that BlueSwordM linked to are a better idea and almost all lights will accept them, spacewise. Simon hasn’t had them available that long but they were a great idea. Best to just hunt down the cells you need, imho. Liion Wholesale will add buttons to cells for a small fee if you contact them. Digikey may also but they might only do nickel tabs, and their selection of lithium is pretty poor anyway.
If you can solder than adding a solder blob is quick and effective.
In applications where it’s highly unlikely you’ll be dropping your flashlight, the small magnet can work. Especially if there’s sufficient pressure against it. With the switch off, firmly rap the side of the flashlight a few times, unscrew the body gently and check the magnet position. I’m using one in my RRT-01 for a flat top 18350 cell and despite some really firm side raps, the magnet showed to stay in place.
I really like the idea of those full diameter contact pcb’s, though. $3 for a set of 4 seems very reasonable.
A long time back I’d gotten a nice delrin spacer with brass center that came with a flashlight, as the maker was aware that some flat top cells might fall short. I couldn’t remember where I’d gotten it. A guy over on CPF was selling an equivalent, though a bit pricey.
Those contact PCB’s above are priced much better.