Using LiSoCl2 primary cell with WisBlock

Hi everyone, I wonder if anyone has already used primary cells with some kind of WisBlock module.
We would require them for low power long term application in harsh environments.
Apart from the danger of charging it when 5V is connected, I think this should work, since LiSoCl2 cell voltage stays over 3.3V when moderately discharged. But I know that some designs use supercaps to buffer the higher currents, e.g. when transmitting LoRa messages.
Any experience around?

Welcome to RAK forum @dansi ,

Lithium Thionyl battery should work fine with WisBlock. A fully charge one can be a bit higher than 3.6V though. Having an LDO might be good idea but I see designs where it is directly connected to modules.

Regarding the supercaps, it really depends on the specs of the battery. Some LiSoCl2 only have peak current written on specs not more than 50mA which might be low. Specially during active state of the node since it is not only the LoRa Module that will be active but also the sensor and other external peripherals of the circuit. You must have an idea what peak current to expect so that you can add the supercap if really needed. If not needed, you can save cost.

I haven’t played around with LiSoCl2 so much so I can share only limited info.

I just did a quick test with two LiSoCl2 from different manufactures. One(Fanso brand) drops to 3.6V from 3.7v while the other one(Xeno brand) drops from 3.7v to 3.1v. I am not sure though if there is something wrong the second battery. Current drawn from WisBlock setup (running RUI3 OTAA example) is not that much.

Hello @dansi

For the use of non-rechargeable batteries, I would propose our new WisBlock Base Boards with Power modules.
You could use any of the RAK19009/RAK19010/RAK19011 Base Board

And as Power Module use the RAK19015 for non-rechargeable batteries:
This has no USB connector, but we are planning to release the same version with USB soon.
In the meantime, you could use the RAK19012 Power module during development

And just switch to the RAK19015 when deploying the device.

Store links:
Base Boards and Power Modules

Documentation links:
Base Boards and Power Modules

Thank you for your answers! I’ll try first connecting to the battery port of my 5005 base. Of course without charging. And then see how the battery behaves. Directly connecting seems too dangerous for me, since I don’t know much about the internal voltages required by the core and the modules.
Later I might use the new base/modules, when they become available in CH.

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