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Awesome
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Discussion Starter · #1 ·
I know a lot of people like to standardize around, and stock up on AA and AAA batteries, but what about larger lithium cell batteries like the 18650s, 21700s, 26650s, etc? I know 18650s used to be VERY popular for things like flashlights, but in many instances I see people moving towards 21750s as you get almost double the capacity for only a bit more length and width. Several tool manufacturers are sticking them in their power tool batteries now as well.

Do any of you standardize battery powered equipment like lights, radios, tools, power banks, or anything else around any of these battery types? If so, which ones, and why? And what are your thoughts on the growing popularity of 21700s?
 

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Awesome
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Discussion Starter · #3 ·
A 21700 has about double the capacity of an 18650 though, and they're not double the price of an equivalent 18650. There may be better value there. You might just get more Ah per dollar with 21700s. If I decide to buy into 18650s or 21700s, I'd probably build everything around that type. There's not much need for AA/AAA for anything important and I think 3x AAA adapters fit 21700 devices.
 

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Awesome
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Discussion Starter · #6 ·
Well many of the newer 18650 and 21700 devices, like flashlights actually have built in chargers with overcharge protection built in. You don't even need a charger. If you have an 18650 or 21700 device that doesn't have a charger, you can use lights to do charge them and swap out. Many of these lithium powered flashlights also function as portable power banks. You can charge a cell phone off your flashlight. I'm working on some details right now for building a portable soldering iron around these batteries. A simple PWM + power MOFSET should do the trick.
 

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Awesome
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Discussion Starter · #10 ·
Yeah, the batteries need to breathe, but also, there are protection circuitry built into a lot of the devices that rely on them, that prevent them from going nuclear. That's another reason the newer lights, the ones that tend to be rechargeable also have those protections in them. And I'd imagine vapes have improved in that area as well. Considering using a vape body for my soldering iron project, I noticed some sold as "mechanical" which have no protections at all. Those would be a great concern to me.
 

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Awesome
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Discussion Starter · #13 ·
People drive all day every day and don’t get into an accident. Then one day when they are doing everything right a dipstick drops a cinder block off an overpass and kills them. Just know the consequences of when things go wrong.
And when you read that story about the overpass, do you avoid all cars afterwards?
 

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Awesome
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Discussion Starter · #15 ·
I think I'm going to start picking up some 21700 devices. I do want to build some portable power tools and 21700s would certainly yield better performance for those things. And a flashlight with a 21700, being only marginally bigger than one with an 18650, has about half the capacity making it better to be used as a power bank as well.
 
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