ESP32-POE (ISO) LiPo Battery Charger Control

[GunnarE]

Hi Everybody,

Is there a way to control (turn on, turn off) the lipo battery charger
on the ESP32-POE and ESP32-POE-ISO boards ?

I have looked through source code and googled, without any luck.

Thanks,

Gunnar

[LubOlimex]

No there is no software control or enable for this. If you don't need the battery charger at all and you need it removed, maybe unsolder and remove one of the components before it. For example, FET2.

But why would you want to do that? The only reason I can think of, is if you wish to use non-rechargeable battery instead of a Li-Po one.

[GunnarE]

Hi Lub,
Thank you for your reply.

The reason to disable it is this: I intend to use the battery to power a motorized water ball valve. and let the ESP32 keep the battery charged.
The esp32 is powered over its POE.

So my idea is to turn off charging while the valve operates.
I control the valve with a relay, and i guess i can put another relay on the battery charger line.
(as you might be able to tell, i am no pro on this (actually, its only my second project)
My thinking is; When the motor is powered by the battery, i probably would want the battery disconnected from the charger circuit to not damage it.

I am open to any and all suggestions and alternatives.

Kind regards,
Gunnar

[LubOlimex]

You don't need to it. The battery and the charging circuit can handle it.

[oguzhan306]

Hi LubOlimex,

I have a similar question, but my use case is slightly different.

I'm using an ESP32-POE-ISO Rev. M in a device that will operate in cold environments, potentially below 0°C.

The device is normally powered via PoE, and I want to use a Li-ion battery strictly as a backup power source in case PoE fails.

I do not want the battery to be charged by the board under any circumstances, particularly because charging Li-ion batteries at sub-zero temperatures can be unsafe.

My requirements are:

When PoE is available, the device should operate from PoE.

When PoE is lost, the battery should automatically take over.

When PoE returns, the device should switch back to PoE.

The battery must never be charged by the board.

A brief power interruption or ESP32 reset during switching is acceptable.

In your earlier reply, you mentioned removing FET2 to disable the charging circuit.

Would removing FET2 on the ESP32-POE-ISO Rev. M completely disable battery charging while preserving the automatic battery backup functionality?

If not, is there another component that could be removed or a simple hardware modification you would recommend?

Thank you for your help!

[LubOlimex]

Removing FET2 won't work in your case. You need to carefully unsolder and remove U3 TP4054 (the battery charger IC). Refer to the schematic. It is SOT23-5 package, chip with 5 pins.