Charging AA Li-ion batteries

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Charging/discharging lithium batteries is dangerous, possibly causing fire or explosion if not done properly, so is best done using a dedicated commercial charger.
Have you read this article?

 

Lithium Ion batteries are not 1.5V, and, as far as I know do not come in AA size.Most likely you are talking about NiMH batteries.

Bob

 

Your statement doesn't make sense. Firstly, as @BobK pointed out, lithium ion cells are NOT 1.5 V. You may be thinking of alkaline cells, which DO have a typical open-circuit terminal voltage of 1.5 V. Unfortunately, alkaline cells are NOT rechargeable.

Secondly, you may be thinking that you have nickel metal hydride or NiMH cells, which have a typical open-circuit terminal voltage of 1.2 V. These are rechargeable, and in AA size can have energy ratings up to about 2000 mAh.

Thirdly, battery charge capacity is typically measured in ampere-hours (Ah) or milli-ampere-hours (mAh) NOT in milli-watt-hours (mWh).

Fourthly, lithium ion cells come in two varieties: primary and secondary. Primary cells are NOT rechargeable and are by far the most common variety, typically used for things like volatile memory backup power during a mains power outage or long-term storage without power. Secondary lithium-ion cells require special charging and discharging techniques, lest they overheat and explode. It is best to purchase a commercial battery charger, specifically rated to charge your particular lithium ion cell, rather than trying to "roll your own," given the obviously little experience you have.

If you want to continue this discussion and conversation, please upload a picture of the lithium-ion cell you want to recharge, along with the manufacturer's name, model number, and possibly a datasheet. Someone here might then be able to lead you toward a good solution if one exists.

 

Amazon sells Chinese AA size Li-Ion 1.5V battery cells that even have a 5V USB charging jack!

 

I think these contain regular 3.7 V Li-ion cells and a buck-converter to reduce the voltage to 1.5 V. Charging from a 5 V USB port would still require some sort of charge-regulating hardware and/or software. And they are a little pricey compared to 1.2 V NiMH cells, but they surely look to be convenient.

 

Oops! It appears both ratings, mWh and mAh, are used to specify battery capacity. My bad. However, the two measurements DO NOT measure the same thing, so you cannot directly compare a mWh rating with a mAh rating. Google "mWh vs mAh" for more information.