Powering an ESP32 via Vin pin

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ray_leiter
 
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Powering an ESP32 via Vin pin

Post by ray_leiter »

Until recently, I never needed to power my ESP32s anyway other than USB.
I recently verified I can power my ESP32 via a 9volt battery connected to Vin.
What about using 2 3.7volt batteries in series connected to Vin?
Is this possible or too troublesome?
Ray

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adafruit_support_bill
 
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Re: Powering an ESP32 via Vin pin

Post by adafruit_support_bill »

Which ESP32 board are you referring to? There are quite a few, and their power requirements vary.
https://www.adafruit.com/search?q=esp32

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ray_leiter
 
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Re: Powering an ESP32 via Vin pin

Post by ray_leiter »

The board I've been using has "ESP-WROOM-32" etched on the chip.
It has "ESP32 DEVKIT V1" on the silkscreen on the bottom of the board.

I'm looking to make it work with Lithium Ion or Lithium Poly batteries and then procure some new boards with on board battery management hardware.
Ray

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adafruit_support_bill
 
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Re: Powering an ESP32 via Vin pin

Post by adafruit_support_bill »

Sounds like one of the development boards from Esspressif. Can you post a photo of the actual board? Or better yet the Adafruit product ID.

Looking at the dev boards from Espressif, I don't see any with a VIN pin.

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ray_leiter
 
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Re: Powering an ESP32 via Vin pin

Post by ray_leiter »

I'm including 2 photos, TOP view & BOTTOM view.
I'm not sure where I got the board, I've had it for some time now and I used it to take tutorials from Random Nerd Tutorials (RNT.com).
I'm looking to upgrade to a "S3" board and the one I'm looking at is "Product ID: 5399".
I'm not ready to discard the ESP32-WROOM-32 board yet. I have a project in mind for it that requires me to power it via battery.
Meanwhile I can explore the use of a more recent design like the "5399".
Ray
Attachments
TOP2.jpg
TOP2.jpg (951.19 KiB) Viewed 107 times
BOTTOM1.jpg
BOTTOM1.jpg (276.96 KiB) Viewed 107 times

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adafruit_support_bill
 
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Re: Powering an ESP32 via Vin pin

Post by adafruit_support_bill »

That does not look like any of the ESP32 Devkit boards that we carry. I would expect that if 9v to the VIN pin works, 2x 3.7v should work also. But I'd expect that just 3.7v should be sufficient. There must be a voltage regulator on the board since the ESP32 module itself runs at 3.3v. The manufacturer of the board should be able to provide more specifics.

The #5399 FeatherS3 - ESP32-S3 Development Board by Unexpected Maker follows our Feather standard. You can power any Feather with 5v via the USB jack, and/or 3.7v via the JST battery connector.

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sj_remington
 
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Re: Powering an ESP32 via Vin pin

Post by sj_remington »

The photo shows an AMS1117 voltage regulator, which has a typical dropout voltage of 1.1V (max 1.3V) and is presumably connected to Vin.

If so, a 3.7V lithium battery will not work well or at all, and voltage on Vin must be above about 4.5V.

Keep in mind that the regulator must dissipate excess input voltage as heat, and if it overheats, it will shut down. A 9V battery is not a good choice for several reasons, but a 5V phone charger would be fine.

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ray_leiter
 
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Re: Powering an ESP32 via Vin pin

Post by ray_leiter »

Bill,
Thanks for your help. I think the #5399 is just what I need. A single 3.7v battery on Vin won't be very reliable (even if it did work.)

sj_remington,
Thanks for the info. I didn't check to see if things were heating up when I used the 9v battery. I only used it for about 3-5 minutes at a time. I'll abandon the idea of the 9v battery.
I think you are correct about a single 3.7v battery not working. Your remark about the use of the 5v phone charger takes me away from the portability that a battery offers, so it won't work either, even though it will actually work!
I notice you didn't comment on the idea of 2 3.7v batteries in series -- do you think it also presents problems?
Perhaps because the batteries are not likely to be the same voltage?

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adafruit_support_bill
 
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Re: Powering an ESP32 via Vin pin

Post by adafruit_support_bill »

2x3.7v (7.4v) should work. But as sj_remington says, anything above the 4.5v needs to be dissipated as heat. Ideally, you want a voltage source just slightly above 3.3v + regulator's dropout voltage. Rechargeable options include:
* a 3.7v LiPo with a boost converter: https://www.adafruit.com/search?q=powerboost
* A 4S NiMH pack (4.8V)

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millercommamatt
 
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Re: Powering an ESP32 via Vin pin

Post by millercommamatt »

A 5V phone charger won't be portable, but those phone charging power bricks that are near ubiquitous are very portable.

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ray_leiter
 
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Re: Powering an ESP32 via Vin pin

Post by ray_leiter »

Bill,
Thanks again for the suggestion of the 4.8v battery pack.
So far, it looks like the best approach.

millercommamatt,
Thanks for the suggestion, I totally forgot about those power bricks.

Ray

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