Weekly reminder that li ion batteries has to be respected

[breakingsymmetry71]

@jon_slider

imo the cause is use of Turbo causing excess heat in the battery, and damaging it over time…

If that true I would be concerned a lot on how it is easy to degrade cells to a state when they are unsafe.

User reported the battery in question is - Samsung INR21700-50S
I found there link to its datasheet on convoy site - here

Per Samsung pdf provide I see it rated 25A for continuous discharge (and it expected that cell wont be heating to above 80℃ per its own internal resistance) and it can handle 45A if you ensure to do cut off when it reach 80℃.

For operational temperature it rated from 0 to 80℃.

@jon_slider

“newer Loneoceans driver lights can reach that kind of surface temperature [80C] from a couple turbo activations. His custom Anduril build has a feature that ignores thermal management under 71°C in turbo.”

Thank you for flagging it out. I remember it was discussed in Artemis thread:

@Bob_McBob

The current Anduril build included with newer Lume drivers has a feature that disables thermal regulation below 71°C in turbo, which makes it very easy to reach burning hot surface temperatures. This is a KR1K after two turbo runs. It took 15 minutes to get back down to the 45°C set point.

@ToyKeeper

But in loneoceans’ fork, it specifically disables that when running at the turbo level. It looks ahead, sees that it’s about to slam into a wall, and explicitly does nothing. It detects an overheat condition and ignores it instead of sending a warning to the UI code. So it slams into the wall. But it doesn’t stop at the wall… it breaks through and continues to do nothing for a while. It doesn’t allow any “steering” to happen until after it has already gone quite a bit past the wall, and is significantly hotter than the user’s configured temperature limit.

… and THEN it tries to begin steering. After it’s already way too hot.

Hence why it got up to 78 C on the outside of the light when configured for 50 C. (or in F, it got up to 173 F when configured to stop at 122 F)

78C on outside can easily mean it 90C on inside which is outside of battery SAFE range.

@jon_slider

because I dont think the cause was the driver..

But if above hypothesis is true then it is a driver issue to me where driver design make it probable to degrade battery to a state when it can explode. Lume x1 driver only consumes up to 10A which is nothing for this battery but heat from leds/driver could be the cause. Otherwise product page should warn that only li ion batteries with operation range up to 100C should be used. But from quick search there no mainstream 21700 that can handle up to 100C. Molicel P60B states 90C as temp cut off but even it recommends up to 60C as normal operational condition.