NodeMCU power supply

Hi

I have NodeMCU, I wanted to know what is the maximum input voltage and amp can NodeMCU support.

Can I plug it with 3.7v (4800ma) x 3 batteries? Total voltage = 11.1volts.
Please let me know if it will not burn nodemcu with that much voltage and amps.

Thanks

What type of batteries ? the voltage makes me suspect that you intent LiPos which actually can be as high as 4.2v, that changes the equation.
Also a nodeMCU runs on 3.3v, so providing it's internal regulator with much more than 3.3v + voltage drop, is going to generate a lot of heat.

Why such high voltage? Is the NodeMCU running at 3.3 volts? Such microcontrollers usually have LDO stabilizers and it may turn out that even just 1 of these batteries is enough to work. I guess the batteries are rechargeable and if they are balanced you can connect them in parallel for much longer operation.

Devices can never have a maximum applied amperage, because it is the device not the source that dictates the current flow. They only have a nominal supply current, then the power supply maximum supply current has to meet or exceed that value.

You can run your NodeMCU on a 1,000,000 amp power supply if you like. But it has to have the right voltage.

Also battery AH is not the same thing as amperage, it's amperes times hours. The maximum output current of a battery, is a different specification.

Five volts. (OK, 5.3 V, see #7)

The CH340 USB interface in the NodeMCU is powered by the 5 V connection, either by the USB connector or pin 1 of the header.


More than 6 V 6.5 V and it fries.

The NodeMCU does not "support" any Amps. Pins can source about 10 mA.

But runs internally on 3.3volt (the V3 pin).
Don't know how much overhead it needs to maintain a stable 3.3volt on the V3 pin.
The same goes for the 3.3volt regulator for the ESP8266.

But OP should indeed use a 5volt buck converter to power the NodeMCU.
Leo..

Datasheet says 4.5 to 5.3 V, and absolute maximum 6.5 V.

It will alternatively operate on 3.3 V to the V3 pin.

I put it on a test of around 10V on VIN pin and it is running non stop without any heat.
I also, added a load of around 5 volts.

What does that mean? There's no such thing as a 'load' of a certain voltage.

Nice to hear your NodeMCU hasn't fried yet. Any particular reason for running it way beyond its maximum limits?

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I am pretty sure the regulator can take up to 12v, and provide current up to 600mA (maybe 800mA) depending on the heatsink. Of course the peak current that is required for a nodeMCU is in the order of 300mA (during WiFi connect), but it draws only about 100mA most the time (still a lot compared to an AVR)

Yeah that is nice, but it's early days still. Not sure the regulator has an overheating protection.
I usually power my ESPs with a 7805 TO-220 package, down to 5v, which doesn't require any extra heatsink, and then regulate down to 3.3v from there. Simple, cheap, compact and reliable.

No doubt it can. But powering the CH340 with massive over-voltage may be a bad idea.

That said, the NodeMCU is very badly documented - I can't say how this version is wired, only that the schematic I cited says the CH340 is powered directly from Vin.

Which, if the schematic is correct, is a completely inexplicable design choice. With an ESP uC the obvious choice is to run the CH340 at 3.3V along with the uC, which is perfectly fine since the 340's USB data pins are still 5V safe in this configuration.

That is one way of putting it.

Well, not really. :face_with_raised_eyebrow:

This is a digital logic system. Digital logic operates at 5 V - or at 3.3 V. No digital logic systems operate at higher voltages, so a 5 V supply is what anyone expects to use for a digital logic system. (I am here being a trifle provocative, but essentially this is the simple fact.)

The problem of providing the standard 5 V supply if you are going to use a digital logic system is an entirely separate matter to be addressed, but expecting what is obviously designed as a digital logic system, to operate on some higher voltage is simply specious.

Oh yes. If you have a board that runs 3.3V logic exclusively and you already have a linear regulator on there, then it doesn't make sense to power one chip from an external 5V (which you never know what the user is going to connect to...) while you could perfectly easily run it from the 3.3V the regulator provides anyway. It doesn't make sense whichever way you try to reason around it. And frankly I doubt the schematic is reliable in this respect. If it were, OP's board would have died long ago; at least its USB-Serial functionality would have. CH340's can't handle any abuse at all.

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