The writer suggests a portable battery tester for checking the health of lithium 18650 cells, which can be removed from various devices such as cordless power tools or vapourisers.
They explain that just because the cells can be charged doesn’t mean they should be used, as they could have a low capacity or fail under heavy load.
To establish their worth, the cells need to be tested, for which the writer suggests a charger that can conduct capacity tests.
Alternatively, they highlight a DIY battery tester that uses a pair of Texas Instruments chips and an ATmega328P microcontroller to test the battery and display the results via LEDs.
This portable device can also communicate charging statistics to a computer if connected.
