Adding battery power to ESP32 project

Lightium said:

How do you expect to get 5 volts from 18650 batteries?

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rjenkinsgb said:

It appears the overall unit can take something like 2A or possibly more at 5V (see here) - the specs say supplies 2A and 1A:

ESP32 Development Board - WT32-SC01 with 3.5in 320x480 Multi-Touch capactive Screen, support Bluetooth & WiFi

WT32-SC01 is a development board with a visual touch screen. The board is equipped with self-developed GUI platform firmware and supports graphical drag-and-drop programming.

www.elecrow.com

As a pure guess, I'd estimate 300 - 600mA with the display on but low brightness and CPU mostly idle. That's 1.5 - 3W range.

Assuming you are using a good, efficient, switch mode regulator module, three 18650 cells (2.5AH each) would have a total capacity of roughly around 27WH. Call it 25WH to allow for 10% regulator losses.

Something like 8 - 16 hours probable operating time; but without knowing the exact operating currents, that could be off either way.


The cells could be in series or in parallel, depending if you use a boost regulator or buck regulator.

If you intend to charge them in the device rather than separately, go with parallel - it avoids the need for cell balancing and the whole thing charges as one large cell on a single cell charger.

Either way, you must have battery suitable battery protection board, connected between the cells and load.

For series cells that must also include a cell balance facility in the same board, unless you are using holders and taking the cells out to charge in a dedicated charger.

Note that the battery protection module (and balance section) is not a charge regulator, it is just to ensure the cells operate within a range where they are not likely to fail or explode.

ps. Any 18650 cells claimed to be 3.5 - 5AH (5000mAH) or more are 99% guaranteed to be fakes, much lower capacity and quite likely no more than around 2AH.

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