Review on MT3608 Boost Converter - Micro USB DC 2V-24V to 5V-28V 2A, Voltage Regulator, Power Supply Step Up Module 3.3V 5V 6V 9V 12V to 5V 6V 9V 12V 24V (Pack of 4) by Matthew Thorndike

Also known as buck converter, adjustable output voltage. up to 15V direct voltage. I used it to see if I could boost it enough to charge a 12vdc power bank. For example, use it to boost the voltage of a solar panel with an output voltage of only 5VDC, boost a 2A power supply to 12VDC, detect and start charging, and also feel very cold. Plugged it into 12V DC car LEDs, saw them draw about 3 amps and it heated up quickly. Connected to a 25 watt grow LED strip, it didn't get hot, but it didn't emit light at full brightness either. All of these tests were tested with a 5000mAh AC adapter for about 10 minutes.