I need to boost 4.2V (out of MPPT/ 18650 battery charge) to 5V (input for ESP8266.) To accomplish that I've bought this item, a 2.0 - 24V boost converter, which supports 2A.

But when trying to do so - though voltage is converted as needed and does not drop during boot - the MCU does not power up.

I tried to add 100 microfarad capacitor at input and output of the converter. No luck.

  1. Is there a way to "fix" this converter to power an MCU?

  2. If not, what type of converter would be suited for the job?

  • 4
    \$\begingroup\$ An ESP8266 runs off 3.3V - why do you need 5V? \$\endgroup\$ Commented Aug 7, 2020 at 20:20
  • \$\begingroup\$ I rather use microUSB port (5v regulated - for more power stability) \$\endgroup\$
    – guyd
    Commented Aug 7, 2020 at 20:38
  • \$\begingroup\$ ESP8266EX datasheet page 23 indicates maximum voltage is 3.6. It's likely that it won't boot because it's damaged from overvoltage. \$\endgroup\$
    – JYelton
    Commented Aug 7, 2020 at 21:00
  • \$\begingroup\$ @JYelton - 5v via USB \$\endgroup\$
    – guyd
    Commented Aug 7, 2020 at 21:08
  • 1
    \$\begingroup\$ some processors have trouble starting if the spply voltage is unstable or too slowly rising \$\endgroup\$ Commented Aug 8, 2020 at 7:01


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