LillyGo T-Beam V1.1 ESP32 board recharge 18650

Ok - have about 5 LillyGo T-Beam V1.1 ESP32 boards now all running V2.0. I can’t find a “direct” answer now, but as I recall, these boards can all recharge the 18650 battery on them. Specs from LillyGo SEEM to indicate that it can charge at 500ma.

So I’d like to find a solar panel with USB output to connect to the board that will keep the board up, AND recharge the 18650. I started messing with this stuff over a year ago, so I’m just wondering about this aspect of these boards.

Also - any suggestions about solar panel output, etc to use for this purpose?

i took just some solar module with up to 18V 500mA output and connected via voltage regulation:
Lm2596s dc-dc 24v/12v to 5v 5a step down power supply buck converter adjustable usb step-down charging module Sale -
works nice …

I’m curious why you did that - instead of just getting a solar panel for USB that output 5V, maybe 1A or 500ma? Seems much easier than getting a buck converter to take the 18V down to 5V, etc. Something like this:

Supposedly 3A (somehow I doubt it’ll output 3A, but whatever)

Main reason: i could just take the solar panels i had from other projects…
some 18V 500mA and one 18V 200mA.
using the converter i can just attach anything i want to power the t-beam, from 5V to 30V :slight_smile:

further more, i expect (and until now it is as expected) the 10W Module to deliver sufficent power (5V 150+mA) for the t-beam also in low light, like wintertime… … a true 5V 500mA Module would only provide this Energy in perfect summer- sunshine…probably not be enough in winter.
In winter time i would expect a 10W module to provide only ! 1-2Wh per day ! on some very weak days…

the module you listed above also is a 18V Module , just with an USB-Voltage-converter built on to it, so nothing else than the device i am using :slight_smile:

i would suggest on of these modules, combined with voltage converter…(put the converter in the housing next to t-beam)

Ok - thought that might be the reason (already had most of the parts) - but wanted to be sure there wasn’t a snake in the grass I didn’t see. Yes, I’ve thought about the lower ambient light situation too. We’re now having 21F mornings around here, so winter is definitely on it’s way.


my setup (above) did not work in winter weather.
I had to change the solar setup.
with 1-2h full sunshine it kept the Battery at 80-100%
but the low light performance of 20W 18V module was not sufficient.
in low light it delivered not enough mA, regardless of the higher voltage…
so did not charge the connected battery.
Now i will change it to an exotic 6V 5A Module , that should deliver the required mA for charging…
i measured energy hunger of the t-beam…
Energy saving on, GPS-Sleep , fixed position
without messages going through the channel: average of 6mA ( 3 hours)
with 1 Message every 60 seconds (rangetest) average of 25mA (3 hours)
but when the router is placed with big antenna in position on rooftop up o a hill, i expect it to be routing many more messages from other channels on same modem settings…
so i expect 25-50 mA Energy consumption…

Good to know. I got a solar panel. SUPPOSED to output up to 5-6W (I seriously question that - but hopefully 3-4 will work at 5-6V.