Hello everyone, hope you can help optimizing this project. I have a project that is remote and battery powered. It is powered by 12V battery, step down to 4.1V, ESP32, SIM module, RTC and various sensors. Project is remote, and I need it to send SMS with sensors readings twice a day; morning and ev…

[image] crovasco: I found this, did you have any updates over this? That's the low voltage version. But you said you're using a 12V battery. I don't think you would want to leave a buck converter running while the power is switched off to the rest of the circuit.

This got me thinking... Main problem with 3.7V battery was that it went rather soon under 3.6V and that was unstable for SIM800L. But with this solution, I could get rid of buck converter altogether. 18650 battery -> ((Is IRF9540 ok?) G -> INT/SQW of DS3231; D -> SIM800L and ESP32) Did I get that…

An 18650 fully charged will be about 4.2V. At 3.6V it would be mostly discharged. So it should be perfect for the SIM. The ESP32 board will probably have a 3.3V regulator on it, but its dropout voltage may be too high. So you may want to use a separate external 3.3V regulator with a very low dro…

[image] ShermanP: So you may want to use a separate external 3.3V regulator with a very low dropout for the ESP32 ESP32 works with 4.2V input with no problems [image] ShermanP: I assume your DS3231 module looks like this: Yes, thats the one.

I started a new thread in the General Electronics section about the mods needed to the DS3231 module. https://forum.arduino.cc/t/mods-to-ds3231-zs-042-module-for-power-control/1101164 [image] crovasco: ESP32 works with 4.2V input with no problems Yes, but will it work at 3.6V?

[image] ShermanP: I started a new thread in the General Electronics section about the mods needed to the DS3231 module. Can you give me desirable specifications of MOSFET, so I can check with local electronics equipment shop to get the right one?

What is the maximum current your circuit will be drawing?

Peak current is for SIML800L is 2A. I will try two options - one is 18650 battery, and the other is 12V battery with step down 4.1 V. I see on the other post you suggest using combination of 2 MOSFETs. Please share sprec for them too. I will post my results when I do testing with both variants.

For the 18650 supply, you just want it to be logic level and have low resistance. I use the DMP1045U. It comes in an SOT package, so you would need an adapter board to make it through-hole. But it has very low GS threshold voltage of 1V max, and on-resistance of about 40 milliohms. I don't know o…

Would you find AOSS21115C as a suitable MOSFET? [image] AOSS21115C ALPHA & OMEGA SEMICONDUCTOR - Transistor: P-MOSFET | ... ALPHA & OMEGA SEMICONDUCTOR AOSS21115C | Transistor: P-MOSFET; unipolar; 20V; 4.5A; 1.3W; SOT23 - This product is available in Transfer Multisort Elektronik. Check …

Battery optimising / Sleep / TPL5110 and ESP32

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crovasco March 13, 2023, 5:13pm 23

Can you give me desirable specifications of MOSFET, so I can check with local electronics equipment shop to get the right one?

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Battery optimising / Sleep / TPL5110 and ESP32

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