Dragon heat and Li Batteries

[Tom Hamilton]

Does anyone happen to know at what temperature Li battery thermal protection circuitry will activate and cut power?

Thanks in advance,

Tom

 

[Björn Benckert]

Does anyone happen to know at what temperature Li battery thermal protection circuitry will activate and cut power?

Thanks in advance,

Tom

It says on the back of the redvolts. As I remember it's 50 degrees. even though that feels a bit low. But we had issues with them in warm waters and dive housing. They basically shut down camera without a warning and the recording clip in camera was lost each time. Took a whlle before we figured out that we needed to make sure to cool the camera differently.

 

[Tom Hamilton]

Thanks Bjorn, that is pretty much my conclusion as well. Dragon core temps run at 65C and beyond, well north of the max temp limits of Li batts. Not an issue in free air, in an enclosed housing underwater an entirely different proposition.

 

[Alexandros Tsoupras]

Off topic. Is this charger http://idxtek.com/products/vl-4s/ compatible and will automatically stop the RED BRICKS when the are fully charged?

 

[Peter Majtan]

Off topic. Is this charger http://idxtek.com/products/vl-4s/ compatible and will automatically stop the RED BRICKS when the are fully charged?

YES and YES. Same exact model I am using...

Back on topic - I actually think this heat issue is what is causing the REDVOLTs in the SIDE HANDLE to loose their ability to hold charge over time.
My 4 REDVOLTs hold at full charge (indicated by the green light on the charger) 85% / 80% / 67% and 63% respectively (the capacity shown when inserted to RED)
Every time I take the REDVOLT out after using it - it is pretty hot. So much so that it has to be cooled down before charging is attempted...

:sifone: Peter

 

[Tom Hamilton]

According to some literature I have read, the ideal operating temperature for Li batteries is from 10 to 45C. The Dragon reports a 65C core temperature, and a 45C sensor temp when up to operating range, any battery in proximity to this kind of heat would certainly have degraded performance and possibly reduced life.

Peter, are you able to measure the temp inside the Redvolt compartment, maybe with a meat thermometer?

 

[Peter Majtan]

Have little more sophisticated gear for that in my R&D workshop.
I have sensors that can measure it and provide live telemetry during the actual use...
Will get on this when my crazy schedule frees up a bit later next week...

:sifone: Peter