TP4056 3.7V 4.2V Lithium Li-Ion 18650 Battery Charger Module Micro USB Adjustable Voltage Booster

Before using, before debugging, the default output is about 9V.
Input voltage 4.5-8V
Output voltage continuously adjustable 4.3-27 V
(4.3V or more, 27V or less, any voltage can be output, you can adjust the voltage counterclockwise)
Charging voltage 4.2V charging current 1A
Discharge current 2A to calculate output current
Output reference maximum current 5V 1.4A, 9V 0.8A, 12V 0.6A
Static current about 0.5 mA
No over-protection over-discharge protection (it can be said that there is a 2 V cut-off increase, but there is still 2 V without blocking the output)
Cut off 2V, depending on the situation, depending on whether to add protection board or not

For example, VIN + termination 5V solar panel BAT + terminal can do 4.2V to 3.7V 18650 battery charging + terminal can produce an adjustable voltage how much you need to set
Can be used for multimeters, modified lithium battery charging