Externally power Thingy:91 without battery

RE: Externally power Thingy:91 without battery

Roshan Nepal — Mon, 09 Dec 2024 14:39:32 GMT

Hi,

Thank you for your help. Yes, it worked! It seems my DC source had some issues. I used a different DC source, and it worked perfectly—both with the JST connector and by connecting the pins to P3.

RE: Externally power Thingy:91 without battery

Achim Kraus — Mon, 09 Dec 2024 14:17:15 GMT

Any update? Does it work now?

RE: Externally power Thingy:91 without battery

Achim Kraus — Thu, 05 Dec 2024 08:25:44 GMT

Before causing damage, let me clarify:

The original 3pin plug uses red for VBAT, yellow for TEMP, and black for GND.

Just the 3pin plugs I bought use other colors. So you need to check your 3 pin plugs not to cause damage.

RE: Externally power Thingy:91 without battery

Achim Kraus — Wed, 04 Dec 2024 16:39:55 GMT

[quote userid="137442" url="~/f/nordic-q-a/116873/externally-power-thingy-91-without-battery/513493"]you kept the temp sensor (black wire) floating, right? [/quote]

Yes, in that test.

If I use a larger 2 pin battery, I connect that with 10k resistor to ground in order to be able to charge it.

RE: Externally power Thingy:91 without battery

Roshan Nepal — Wed, 04 Dec 2024 16:37:58 GMT

Thanks. It might be the case that my JST connector is broken, since I cut it off from the battery. I have ordered a couple of them and will do a test with the new one tomorrow. Just to make sure I understand your setup correctly, you kept the temp sensor (black wire) floating, right?

RE: Externally power Thingy:91 without battery

Achim Kraus — Wed, 04 Dec 2024 15:26:54 GMT

"works on my machine".

The 3pin 1mm JST has different colors compared to the battery.

red is VBAT+ (PPK II VOUT)

yellow is GND (PPK II GND)

black is temp. sensor.

The picture unfortunately doesn't show, that I removed a jumper, which connects the resistor as temp sensor, so that's wire is left open.

RE: Externally power Thingy:91 without battery

Achim Kraus — Wed, 04 Dec 2024 13:56:43 GMT

AFAIK, that's a charging protection including the temp. sensor.

I will (re-)check that with one of my Thingies in the evening.

RE: Externally power Thingy:91 without battery

Roshan Nepal — Wed, 04 Dec 2024 13:51:31 GMT

Yes, I was referring to the temperature sensor. I powered the Thingy:91 using a DC power supply set to 3.7V with a current limit of 1A. The the device never drew more than 30 mA of current.

I noticed that the battery it came with has a small PCB attached. Do you know the purpose of this PCB? I even attempted to connect the two terminals of the PCB directly to the DC power source instead of the battery, but it still didn’t work. However, when I reconnected the original battery, the device suddenly worked again.

RE: Externally power Thingy:91 without battery

Achim Kraus — Wed, 04 Dec 2024 06:39:40 GMT

The JST connector has GND, temp sensor, VAT.

What is the "signal part"? The temp sensor? I use a 10k resistor to GND. AFAIK, that's only required, if the battery is replaced by an other battery.

> I tried leaving it unconnected, and while the Thingy:91 powered up, it didn’t seem to search for an LTE signal or attempt to send one.

Interesting. Maybe I find some time to retest it, but in my memory, it's not required to connect the temp. sensor.

From other tickets (and my experience), if LTE doesn't work, your power supply is too weak. How much current will that deliver? Go for at least 500mA.

RE: Externally power Thingy:91 without battery

Roshan Nepal — Wed, 04 Dec 2024 02:31:13 GMT

Hi Achim,

Thank you for the suggestion! Could you please clarify how the signal port of the JST connector should be handled? Should it be left floating? I tried leaving it unconnected, and while the Thingy:91 powered up, it didn’t seem to search for an LTE signal or attempt to send one.

RE: Externally power Thingy:91 without battery

Roshan Nepal — Wed, 04 Dec 2024 02:26:05 GMT

Hi,

Following the suggestion, I disconnected the battery from the board (connected via a JST 3-pin wire) and supplied a 3.7V DC source through the P3 port. While monitoring the current consumed by the board, I noticed fluctuations between 5 mA and 30 mA. However, I expected the board to use higher current, with noticeable spikes if it were functioning as intended.

I’m using this module to log temperature readings to Microsoft Azure Cloud, but the board remained unresponsive, cycling through this 5 mA to 30 mA range without taking any action.

Thinking the board might require a 3-terminal input (similar to the JST 3-pin battery connection), I removed the small PCB attached to the battery (I’m unclear on the purpose of this PCB—please see the attached photo for reference). I then directly connected the two battery terminals to the DC source, but the issue persisted, and it just used an almost constant current of around 20 mA.

Interestingly, when I reconnected the battery, the module resumed its normal operation, successfully logging temperature readings to the cloud.

This behavior is puzzling, as I’m unsure if I made an error in the connection process or if there’s a different approach I should try. Could you clarify why the P3 port did not function as expected, why connecting the DC source to the battery port didn’t work, and whether there's a specific way to connect the DC source to ensure proper operation?

Looking forward to your insights.

Thanks,

Roshan

RE: Externally power Thingy:91 without battery

Achim Kraus — Mon, 02 Dec 2024 19:54:43 GMT

In my experience, the easiest way is to use a JST 1mm 3pin wire. You will find them in several web-shops.

RE: Externally power Thingy:91 without battery

Bendik Heiskel — Mon, 02 Dec 2024 15:12:03 GMT

Hi,

There's no direct way of disconnecting the battery without removing it. There are solder bridges that can be cut to disconnect the nRF9160 and the nRF52840 from the outputs of the onboard PMIC, but these are indented for measuring the current draw of the two devices independent of the rest of the circuit.

There is 3 voltage rails on the Thingy:91:

VSYS: which powers the nRF9160, it's the VSYS output of the ADP5360 PMIC, which is tied to the battery voltage.
3.3V which powers the RF frontend, LEDs, buzzer and color sensor.
1.8V which powers the nRF52840, accelerometers and the pressure/humidity/temperature/gas sensor.

All of these must be supplied for the thingy to function properly. My recommendation for powering the Thingy:91 externally is to remove the battery, as use P3 to supply the input of the PMIC with 3.7V, and let the it regulate the 1.8V and 3.3V lines.

If you want to have a closer look at the schematic you can find the full design files for the Thingy:91 here:

https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/dev-kits/thingy91/hardware-files/thingy91---hardware-files-1_6_0.zip

Best regards,

Bendik