Hello SparkFun support team,
We have been testing the SparkFun GNSS Flex pHAT kit (mosaic-X5 & IM19 IMU - GPS-29889) and are concerned about the mosaic-X5’s temperature, even though the hardware manual specifies an operating temperature range of -40°C to +85°C.
Tests conducted at an ambient temperature below 25°C with the kit on a workbench (no case):
Firmware version 4.15.0
Scenario 1 (Base mode, only COM1 active):
Over a one-hour period, the temperature rose from 40°C to 63°C.
Scenario 2 (Rover mode, with 4 IP streams, web interface, and disk logging active):
The temperature easily reaches 75°C.
Another mosaic-X5 unit for comparison:
Housed in an aluminum case—where the mosaic-X5 itself does not touch the case directly, but its PCB makes direct contact (via mounting slots)—we observe an average temperature of around 50°C (Base mode, with only COM1 and COM2 active).
Firmware version 4.14.4
Could the small dimensions (44.0 mm x 34.0 mm) of the mosaic-X5 and IM19 GNSS Flex Module be insufficient for heat dissipation?
The GPS-29889 kit will eventually be placed in a sealed enclosure, which could lead to even higher temperatures.
Could the firmware version be a factor, or is the IM19 transferring some of its heat to the mosaic-X5?
Could the IM19’s accuracy and stability be affected by this high temperature?
What are your recommendations, as well as those from Septentrio?
Thank you.
Hi @marcos_aurelio ,
The IM19 draws around 100mA, and so contributes approximately 0.3W. Could that be causing a temperature increase? It certainly seems possible.
For your application, I would suggest trying the IMU-less version of the module and / or installing a heatsink and small fan on the X5 itself.
Thank you,
Paul
Hi Paul, how are you?
I emailed support@sparkfun.com, and they asked me to get in touch via this forum; since it’s my first time doing this, I found that a bit unusual!
I bought this module because I need both components, and I assumed that if it’s being sold on the SparkFun website, it must have already passed certification and quality control.
If the IM19 is contributing to the mosaic-x5’s temperature rise, don’t you think the hardware development team should have anticipated the proper integration between them? Or could I have a defective component?
I haven’t reached the IM19 configuration stage yet; is there a command to disable it? I think that might help us better identify the source of the temperature increase.
What should I do now? Do I need to contact the IM19 manufacturer and Septentrio?
How can I ask the SparkFun engineering team to simulate this in their lab to verify the safe operating temperature for SKU: GPS-29889 while maintaining proper performance for both the mosaic-x5 and the IM19?
In my setup, the SKU: GPS-29889 is positioned away from the Linux Single Board Computer (SBC), so the SBC is definitely not contributing to the temperature rise.
Sorry for all the questions and for the English (I’m using a translator), but I’d really like to get this module working properly.
Thanks.
Marcos Aurelio
Hi Marcos (@marcos_aurelio ),
We are using the exact same mosaic-X5 with IM19 Flex module in the SparkPNT Facet FPM-T. It works well. No Facet FPM-T users have raised concerns about the X5 temperature.
When I have time, I will test the with-IMU and without-IMU Flex modules, side by side, so I can measure any extra temperature rise caused by the IM19.
We have no control over the way you choose to mount the Pi HAT and Flex module within your equipment. If the ambient temperature inside your equipment takes the X5 beyond its operating limit then, I’m sorry, but that is on you. You will need to take steps or precautions to reduce the X5’s temperature, just as you would with the processor on your single board computer. Installing a heatsink and fan would be a sensible way forward.
If you think that is unreasonable, then perhaps you could consider a different design based on the SparkFun Triband GNSS RTK Breakout - mosaic-X5 plus the SparkFun 9DoF IMU Breakout - IM19?
Best wishes,
Paul