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NodeMCU Solar powered

PostPosted: Fri Dec 09, 2016 4:19 pm
by MG89
Hello everybody, im trying to setup a weather station with a Nodemcu board and a solar power bank but it seems not quite effective, I'd like to attach a solar panel and a Lipo battery on it, so if someone could help me with it, I'll be grateful (e.g. stuff to buy or tutorial to follow) thanks :D

edit. I've found this schematic, i think i could use it for my nodemcu (lolin) which it has Vin 5V

Re: NodeMCU Solar powered

PostPosted: Tue Dec 13, 2016 7:07 pm
by Matthewk
This sounds like a cool project, and it looks like you have a good handle on it. I would perhaps go with another module, such as an 01 or 07. A module without the on board 3.3V regulator. I would look on ebay for a switching 3.3V regulator and use that. The more typical regulators on the boards are pass element regulators that dissipate the voltage difference as heat. A switching regulator is much more efficient. The steady state dissipation of that regulator will be many times the power consumption of the 8266 when it is deep sleeping. The other thing I would so is nix all of the LED's on the boards. Again, the LED's are just wasted power.

I would start with a bench power supply and a few ohms in series with the V+. Hook your scope up across that resistor and get a picture of the current consumption. My guess is you are going to see a lot of little spikes, which is why just using a DVM would not be a good idea. Once you have an idea of how much power you are going to be consuming, you can start to figure out what you need for solar cells and batteries.

Don't forget that we are going into winter. That brings up some issues for solar. One is that the days get a lot shorter so you want to make sure you can top them off on the worst of days. Next, if you are in a cold climate, you may get snow or frost build up on the solar panels (assuming that this will be outside and unattended..) Clever mounting of the solar cells can help with snow. Keep them as near vertical as possible. Next, most batteries don't work at peak efficiency when they get very cold. Don't forget that a battery is an electrochemical reaction and most chemical reactions are retarded by cold. Packing the battery pack in some foam or other insulating material may help there. And last, if this will be outside and unattended, it is going to get hot and cold so there will be both expansion and contraction issues as well as dew issues. Putting everything but the sensor in a very tight fitting enclosure may help there, as well as adding a bag of silica gel.

I have not pondered running an 8266 on solar, but I have often times pondered making a solar powered wifi repeater to get a decent signal in my woods, and they seem to share a lot of issues.

Your sounds like a cool project. Please follow up here if you move on it!

Re: NodeMCU Solar powered

PostPosted: Wed Dec 14, 2016 3:42 am
by MG89
thx for the answer, I'm using nodemcu because I had it laying around home, if you have a better choice to suggest, be my guest :D keep in mind I'm going to use a DHT22 and BMP180 sensor right, and in the future I'd like to add an anemometer and a rain sensor , 2) I live in Italy so it's pretty sunny even in winter ;)

Re: NodeMCU Solar powered

PostPosted: Mon Dec 19, 2016 8:17 am
by Sille
Hey guys

nice project by the way I also try to get my ESP working with solar power but I have a basic question which could maybe interesting (maybe not). Anyway, I saw the feather-module from adafruit and there is a lipo charger already implemented which is very nice if u want to use batteries because it switches automatically between the supplies if the module is plugged to an usb aditionally.

My question is: Is it possible to plug a nodemcu devkit (version 2) to usb port for debugging or coding purposes during it´s powered from a lipo?