I need to power a NodeMCU (as far as I know it can work with 3v3 but I use some I2C modules that need 5V so let's power everything with 5V.)

  • I have a Li-ion battery (3.7V.)
  • I have a TP5046 based module (here) to manage the loading / discharging of the battery

This will lead to a rechargeable 3.7V power supply.

Then I have a one of those cheap power boosters from China (here) that brings the voltage up to 5V.

I'm a hobbyist electronic and I like to think about my modules as Lego pieces that I plug here and there. Any recomendations on how to piece the things together?

This is my proposal:

enter image description here

  • \$\begingroup\$ Do you have the schematics for the "TP5046" module? \$\endgroup\$ – Ale..chenski Oct 5 '18 at 17:11
  • \$\begingroup\$ nup, sorry, bouth it from the link stated in the question.. that's all I did :) \$\endgroup\$ – javirs Oct 8 '18 at 6:24

The nodeMCU can be powered by the TP5046 module by connecting it to the '5v' and GND pins.

You don't mention which i2c module needs 5v but most of them can actually be supplied a range of voltages. They often have an onboard voltage regulator which drops the '5v' input to 3.3v.

You probably don't need the boost converter and you should first try it without. It will be more efficient this way.

  • \$\begingroup\$ Do you mean the board has a +5 output port? I think I get 3.7V. Up to 4.2 if the battery is fully charged what can be too much for the nodeMCU when powered straight from the 3v3 pin.. Isn't it ?? \$\endgroup\$ – javirs Apr 17 '18 at 14:51
  • \$\begingroup\$ and down to 2.1 when near to discharge, which is to low if connected to the 5V port in the nodeMCU... \$\endgroup\$ – javirs Apr 17 '18 at 14:52
  • 1
    \$\begingroup\$ No. The board doesn't have a 5v output. I also didn't say to hook up the battery to the 3.3v port... \$\endgroup\$ – Martin Klingensmith Apr 18 '18 at 13:28
  • \$\begingroup\$ So.. if I get you right. I should connect the output of the TP5064 to the 5v input on the nodeMCU. But.. the battery can go as low as 2.1V will this be good enough to power the 5v rail in the nodeMCU (and therefore the internal voltage regulator to 3v3) ?? \$\endgroup\$ – javirs Apr 19 '18 at 6:24
  • \$\begingroup\$ A boost converter can provide a clean 5V despite the range of input from ~2.7V (0% battery) to 4.2V (100% battery) which itself might not work on some boards which are designed for 5V. However, yes, test it out first at all applicable voltages (2.7 to 4.2 should suffice in my opinion) and if it works, then you can leave out the boost circuit. If it doesn't work at lower voltages then you need to use a boost IC, just to guarantee the NodeMCU works all the time despite the battery's voltage. \$\endgroup\$ – QuickishFM Aug 14 '20 at 11:25

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