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My favorite are the ones with built-in USB-C charging - they are so handy to have around! Posting here to help more people discover them:

https://www.amazon.com/MXBatt-Rechargeable-Battery-Capacity-...

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Someone in the reviews posted test results and found they only had a 253-333mAh capacity at 1.5v (so 0.5Wh). 10440 lithium-ion cells (which closely match AAA size) have 250-350mAh at 3.7v (say, 1.295Wh).

If they actually had the 1200mAh capacity they say they'd have 1.8Wh which is much higher than a straight lithium-ion cell without the charging and voltage regulation circuitry taking up space.

I believe the review knocking the capacity, but I'll note the label says 1200mWh, not mAh.

Though even at their promised capacity, that's barely better than a normal rechargeable AAA.

I’m nervous that they’ll have poor or defective BMSes and catch fire.

Yeah, this worries me a bit! Never seen any issues, and I'm only using them in low-impact environments (keyboards + mice), and only charging while present.

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