Those high-current lithium AA and AAA cells

[Mark Hammer]

Ali Express keeps stuffing my mailbox with ads for various high-current rechargeable lithium batteries.  The idea of 6800mAH from an AAA, making an 8-pack a small powerful source of clean  power, is quite seductive.

In past (and I mean past), several of us here had recommended to people plagued by noisy supplies that a 6-pack or 8-pack of C or D cells could provide a valid alternative.  But AAAs are even more compact.  Not quite as cheap as a made-in-China (Caline, Amoon, Donner, et al) power brick, but it reduces AC outlet needs by one.

Any caveats to note?

[R.G.]

The biggest caveat is that 6.8 A-Hr in a AAA is likely to be a tad exaggerated. There is a history of ebay and aliexpress lithium batteries being over-advertised.

It is great if it's true, but verify.

A point to consider is that the electrochemical nature of lithium ion cells is a cell voltage of 3.6V nominal. Any lithium AAA would have about that voltage. Lithium-ion doesn't come in 1.5V cells. A better choice would be three 18650's (between C and D size) and a regulator of a couple of dropping diodes.

There are many newer sizes of LiIon cells, but the 18650 is a well-known standard, widely produced and economical (for Li-Ion).