Post #953046

2026-03-26 17:37 UTC

Anyone use rechargeable 9V batteries before? Any success stories? Bewares? So many no-name brands. So many made-up specs. How’s one to choose? Kinda like the idea of the ones with the included USB-C. Probably eats into room for battery (and capacity) but at least don’t need some one-off charger.

Replies (4)

@howtophil@oldbytes.space 2026-03-26 17:57

@colinstu I had the rechargeable AAs that had the USB port (like a lot of 9v ones do) and that burned out the power going to my USB hub in my laptop...

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@Cal@kind.social 2026-03-26 18:01

@colinstu 9V batteries have such a low capacity that a bit of circuitry inside probably doesn't make a huge amount of difference? Also you can get AA/AAA/9V combined chargers, that's what I use when my smoke alarm batteries need changing

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@LeoBurr@tiggi.es 2026-03-26 23:14

@colinstu I’ve had luck with Maha Energy PowerEx 9Vs.

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@snowfox@tech.lgbt 2026-03-27 15:24

@colinstu Haven't used them, but the NiMH ones are often 7x1.2 V, whereas I assume the ones with a USB port use LiPo and possibly a boost converter. (Not sure if there are LiPo ones that work on a standard NiMH charger.) It also wouldn't surprise me if the space used by the USB port/charge circuitry was less than the space wasted by/between alkaline/NiMH cell packaging. What's the use case? I haven't looked into them because the things we have that take 9V (multimeter, smoke alarm) benefit enough from low self-discharge of alkalines that rechargeables don't seem worth it.

Open ##1295237