Are 5V solar pannels without voltage regulator fine for the T-Beams V1.1?

1

I am planning to use unprotected Panasonic NCR18650B batteries
for my LILYGO TTGO Meshtastic T-Beams V1.1 .

Is it okay and save to charge them with a solar pannel that outputs
5V without any additional regulator electronics ?

These do not have a regulator but have a Micro USB output which is handy:

while this comes with a voltage regulator module has a mobile phone charging protocol :

As far as I understood the LILYGO TTGO Meshtastic T-Beams V1.1
do have already voltage regulator included, so using 5V Solar pannel
without extra voltage regulator should be fine, shouldn’t it ?

Thanks
Lixus

2

Not sure I have the answer to your question, but it sounds reasonable.
I installed a mini voltage display so I can monitor the voltage. Mainly watching for overvoltage above 4.2v. By all rights we should only be talking and using LiFePO4 batteries, especially if buying directly from China. We don’t need the high surge option with standard Li-ion batteries, which are less stable than LiFePO4. Aliexpress has batteries and cheap charger boards for both. Not a lot of data on this solar setup, so I went with a “matched” set with charge controller from Adafruit. I have read where people suggest a 30w minimum panel…I don’t think so. This panel is only 3w and so far so good. But I do live in Arizona, so locations could be a major factor.
In general, why not put a micro solar controller. They’re dirt cheap and offer additional protection- some with freeze and overvoltage protection and without going to a full MPPT expensive controller.
Food for thought…

Adafruit Solar Kit
Adafruit Solar Kit969Ă—722 126 KB

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Panel mounted
Panel mounted360Ă—640 54.9 KB

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3

If you charge through the board USB connector, yes it should be safe. Beware, however, that solar panels output voltage drops under high currents, so you want to make sure the panel operates at a current it can handle easily.
Myself I use TP4056 IC with an adequate current control resistor so that the voltage remains high enough all time and the efficiency is good.

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