LoPy 4 - Current consumption and Deep Sleep

[jmarcelino]

@cduplouy
I tried your code and you setup and even with an UART adapter connected I get 50 μA when the board enters machine.deepsleep()

Can you give some more details please , how are you measuring the current consumption? Are you powering through the Vin pin (top right)?

[cduplouy]

Well ...
I got a second LoPy 4 to run the exact same tests and codes ... And it worked ! With a consumption of 25uA in Deepsleep.
I was indeed powering the LoPy through the Vin Pin with a pico ammeter in serial between the power supply and Vin Pin.

It seems there are different batches of LoPy 4... And one of them includes non working devices with Deepsleep. I noticed a slight difference on the label. I can post pictures of the two devices tomorrow.
But we should definitely notice pycom about that.

Anyway, thank you all for helping me :) !

[livius]

@cduplouy

yes, show pictures - i am also interested it there is some difference between devices

[cduplouy]

@livius

Here's a picture of the two different devices

[jmarcelino]

Hi @cduplouy

Can you post photos of the back of the device please. Since it may have serial numbers please email it to me at jmarcelino@pycom.io

Also please let me know where you purchased them.

Thank you.

[jmarcelino]

Just an update, we do have both devices internally (I'm still checking why there are two stickers). We've tested and both should give good deepsleep results.

Can you confirm you are doing exactly the same deepsleep test on both devices? If so it's possible there is some physical problem with the higher current one.

However the problem is not related to which sticker your device has.

[Gomez]

Hi,
same for me with FiPy and expansion board. Tested with a battery pack made of 2 x 18650, during deepsleep power consumption is around 18-30 ma. Also tried to remove the RTS,CTS and LED jumper as suggested in other post ( RTS e CTS to avoid the TTL to USB converter maybe stay in high power "consumption mode" ) ans 180 ma during main.py processing and Sigfox transmission.
Regards, Andrea

[jmarcelino]

Hi @gomez,

The FiPy issue is completely unrelated, that's due to in some cases the LTE modem not being properly put into deepsleep (airplane mode). We're working on it. Please see this post: https://forum.pycom.io/post/15268

[cduplouy]

@jmarcelino
Thanks for the update.

I confirm I use the same files to make my tests.

I got 3 other LoPy 4. I'm going to run some tests on them as well and I'll keep you updated.

[cduplouy]

@jmarcelino

Seems like I was really unlucky ...
There's only one LoPy 4 that doesn't work in Deep Sleep mode !

I am around 40 to 50 uA with all of the other LoPy 4.
Do you know if that is the lowest we can get ?

[jmarcelino]

@cduplouy
That's expected, are you using machine.pin_deepsleep_wakeup()? I found that increases consumption a bit more compared to timer deepsleep.

There's also around 16 μA loss due to going through the voltage regulator. For even lower power consumption we recommend the OEM module which can be powered directly at 3.3V. (don't power the LoPy4 without going through the regulator on Vin, unless you physically remove it)

If you get our OEM reference board and the OEM module you can also remove a resistor to disconnect the voltage regulator.

[cduplouy]

@jmarcelino

I tried with my power supply through the Vin Pin at 3.7V. I get 40 to 50 uA in Deepsleep
Then I tried with my power suply at 3.3V and indeed i had like 24 uA !

Thank you again for your help

[chippy mathew]

@cduplouy I am also getting around 15mA during deepsleep. I tried with 3.3v and 3.7v using resistor but then it is not sufficient power for the pycom to run.