Is it necessary in sub-zero temps to unplug my Pro 4 cameras to avoid battery damage in charging ?

[MTMtns]

I have read a number of posts here regarding cold temperatures.   I apologize if you feel these questions have been answered.

I have a new Arlo system.  I have several outdoor cameras Pro 4 XL .  I have them in horse/burro stalls.   We have power there, so the cameras are left plugged in (e.g. not used wirelessly).

We regularly have -4 to -20 temperatures, and I realize this is far below the stated operating range.  But my cameras actually worked pretty well in those temps, with only occasionally getting the camera-too-cold warning.  

Questions:

1) I leave my cameras plugged in.  Is it guaranteed that I am damaging my battery when continuously charging in sub-zero temperatures, whether or not I get the camera-not-working error message?  Does the % at capacity matter, e.g. my batteries are always showing 100% when always plugged in.  

2)  What are the model numbers of the 'old', pre-Pro, wired,  etc, Arlo cameras that various posters have mentioned <will> operate in lower sub-zero temps?   Is the point that these older cameras are not able to be wireless, thus there is no battery to damage while charging, or is there some other difference in the old camera and newer ones that allows performance in cold temps?   I can still return my system and get an older one if available...

Thanks for any help.

[StephenB]

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@MTMtns wrote:

1) I leave my cameras plugged in.  Is it guaranteed that I am damaging my battery when continuously charging in sub-zero temperatures, whether or not I get the camera-not-working error message?  

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The camera won't charge the battery when the temperature is below 0C/32F  So no damage due to charging when sub-zero.  Also, the camera will be running on the AC power, so the battery won't discharge.

Arlo also says the cameras have over-charge protection, so leaving them on the charger all the time should be fine.