# NiMH Battery chargers

**URL:** <https://boards.straightdope.com/t/nimh-battery-chargers/854717>\
**Category:** In My Humble Opinion\
**Created:** [May 30, 2020, 4:48am UTC](https://boards.straightdope.com/t/nimh-battery-chargers/854717 "2020-05-30T04:48:10Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Do\_Not\_Taunt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/do_not_taunt/32/2968_2.png) [@Do\_Not\_Taunt](https://boards.straightdope.com/u/Do_Not_Taunt)\
**Post date:** [May 30, 2020, 4:48am UTC](https://boards.straightdope.com/t/nimh-battery-chargers/854717/1 "2020-05-30T04:48:10Z")

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I’m thinking about upgrading my home battery charger. Curious what recommendations folks might have. I’d like a relatively fast charger - I have a recollection of using one that would charge AAA’s in about 20-30 minutes, but now most of what I’m seeing for the fast chargers is more in the ballpark of 1.5-2 hours for a 1000 mAh AAA. Is my recollection wrong? Is the 1.5-2 hours about the best I can do?

Also, I’m seeing a bunch that have a button to switch to a discharge mode. [This one](https://www.amazon.com/dp/B075MBQMFJ), for example. Are there any chargers that auto-discharge and then switch to charging once it has the batteries empty? Or is that always going to a manual switch/button?

In terms of general specs, I basically need to charge AA and AAA’s, though it’d be nice to be able to charge other battery sizes too. Maybe I’ll buy some someday. And I definitely need to charge batteries independently. None of this pairs stuff.

Anything else I should keep in mind?

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**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\
**Post date:** [May 30, 2020, 5:04am UTC](https://boards.straightdope.com/t/nimh-battery-chargers/854717/2 "2020-05-30T05:04:12Z")

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Fast charging (step-differential charging) for NiMH batteries seems to be an initial blast at 1C, then letting the battery cool down for a few minutes, then continuing at a lower current, and so on. So 1.5-2 hours seems about right, unless it’s a special battery designed for ultra-fast charging.

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**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\
**Post date:** [May 30, 2020, 1:20pm UTC](https://boards.straightdope.com/t/nimh-battery-chargers/854717/3 "2020-05-30T13:20:46Z")

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All my current chargers, other than ones dedicated to specific camera batteries, are [Nitecore](https://www.nitecorestore.com/NITECORE-Chargers-s/1869.htm) units.

Some charge 4 cells at once, and one can do eight at a time. All my flashlight cells are 18650 Li-Ion, but I also charge some NiMh AA and AAA cells as well.