Fast battery drain on one RuuviTag

[Chris81]

Hello,

i bought 4x RuuviTags approx. 1,5 years ago and one of the RuuviTags drain a battery in ~115days, the other three run still on their first battery.
I measured the average current draw from the battery at 3.0V and a good one has ~35µA and the faulty one has ~250µA.
Other than the high current draw everything works fine, measurements of all sensors are working and the PCB looks good to me.

Has anyone had a similar RuuviTag with high battery drain?

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Full disclosure:

I used the ‘fault / high battery drain’ RuuviTag in the beginning to flash a different firmware (i compiled the original RuuviTag Firmware myself and tried to change the settings to make it send less often).

After discovering the ‘longlife/longmem’ firmware i flashed it and used it until now. As the first battery went out i inserted a new one and it took ~115days for the battery to reach 2.0V.

I do not know if the high current was there when i bought it or if something was changed by the firmware or flashing the RuuviTag. Maybe there are fuses in the nRF chip?

Yesterday i used the nRF Connect Software to erase the whole chip, programm v3.32.0-RC3_full and then use the RuuviTag App to update OTA to v3.31.0. The current draw before and after flashing was the same so i do not think the firmware flashed to the RuuviTag is at fault here.

I measured the I²C pull-ups (they are both 1k as in the schematic) and looked at the PCB under a microscope and did not see anything suspicious.

Any suggestions on where to look or what to check next?

[otso]

Hello,

Sometimes RuuviTags outdoors get condensation and that produces contaminants that cause leakage current, 35 uA sounds about right and 250 uA is absolutely too much.

It is also possible that there is a problem with one of the components or solder joints that causes leakage current, e.g. a tin whisker has grown across some pads.

Please contact sales@ruuvi.com, link t his post and we’ll figure out the next steps.

[Chris81]

Thank you for the reply, i sent a mail as suggested

[Chris81]

Hi,

did you receive my mail or maybe it did get lost?

In the meantime i made some pictures of the PCB:
(Please ignore the red + black markings on the botom and the ‘flares’ around the battery connector, that is just a scanner error on highly reflective items)

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Maybe the high current is because of a sensor not going into standby?

What would happen if i desolder one sensor after another, would this bring the the firmware to a halt or would it continue to read the available sensors?

[Marko]

Hi @Chris81 please write to us again if for some reason we didn’t reply from sales@ruuvi.com , very sorry if you didn’t get a reply.