I am using a 20W solar panel, maximum voltage 21V & maximum current 1.23 A. I am using LM2596 to dtep-down to 5V to charge my powerbank, hich will later power my Nodemcu (ESP8266 board.)

Issue in conditions I am getting 14V and when connecting it to LM2596 it's lowering it to 1.6V and not going up to the desired 5V.

Am I doing something wrong? Am I missing something? Any suggestions?

Note : I am using standard LM2596 potentiometer module.

  • \$\begingroup\$ what is lowering to 1.6V? then the solar cell? or the LM2596? \$\endgroup\$ Commented Jun 11, 2020 at 7:15
  • \$\begingroup\$ Are you using one of these step down that you can regulate by twisting a potentiometer? I suppose you bought one of these pcb that has an LM2596 and a potentiometer which allows to final tweak the output voltage to be even lower than 5V. Share some more info about what hardware you are using. \$\endgroup\$
    – max246
    Commented Jun 11, 2020 at 7:30
  • \$\begingroup\$ @Jasen My Solar is Giving 14Volts but, my LM2596 Standard module is giving 1.6V no matter what I do. \$\endgroup\$ Commented Jun 12, 2020 at 8:50
  • \$\begingroup\$ Please provide link to datasheets. A circuit diagram helps immensely. If there are inductors etc then please specify. \$\endgroup\$
    – Russell McMahon
    Commented Jun 14, 2020 at 12:31

1 Answer 1

  1. with no load on the output of the LM2596 module, make sure that the output voltage is 5V as you expect, if not tweak the potentiometer until it is, Always turn these things slowly, I have had multiple of these modules detonate if the wiper arm gets too close to ground (too high a voltage on the output capacitor)

  2. With a load connected, if this drops to 1.6V again, does the solar panel voltage on the input also fall? if the power bank is trying to charge at a higher current than the panel is capable of, it may pull down the output voltage,

  3. If the output is being pulled down, you may have to add some resistors to the USB data lines to tell the power bank to use a lower charge rate, not all power banks actually respect this, but it may help,


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