ESP battery draining quickly via transistor?

ESPHome
1

Hi all!

I have a battery powered device (Christmas decoration) which is difficult to turn on by hand, hanging quite high.

This sounded like a good use case for automation using ESPHome!
I’ve 2xAA batteries to power the ESP chip and the decoration is using 3xAA batteries.
To safe battery life, I implemented deep sleep to check every 5 minutes a helper in home assistant to determine if the decoration should turn on, otherwise sleep again.
The ESP controls a transistor that turns on the decoration.

After 2 days (decoration turned on for about 12 hours), the device turned offline and I had to replace the batteries (2xAA) that are powering the ESP. After replacing the batteries, it works again. While the decoration is turned on, the ESP is not in sleep mode.

What am I doing wrong here? Is there maybe something wrong with the wiring? Is the decoration consuming the power of the ESP batteries? Is 12 hours the possible maximum if the ESP is running for such an amount of time on these batteries?

Probably a rookie mistake but hard for me to debug, help would be appreciated!

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Edit: Deep-sleep is working, I have the wiring in place but it is not drawn above. I checked the logs and verified that it goes to sleep and wakes up fine.

2

This:

The ESP draws about 150 to 250mA when on. Assuming your alkaline AA batteries have a capacity of 2200mAh that’s only 8 to 15 hours of operation.

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3

I should have looked up the numbers and do the calculation. I was fully convinced it had to do with the wiring…

Is it possible to have the GPIO pin high while the device is asleep? I would like to have the decoration turned on, but I cannot think of a way of powering that transistor while being asleep.

4

I think that a pulse relay is your answer: you wake up esp, toggle relay and go back to sleep. Additional benefit is that you don’t waste energy for energized relay.

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5

I had to seach for it but I’ve found a latching relay on 3v. Works like a charm. Thanks for providing this solution :+1:

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