[TangoLimaSierra]

Did they not have batteries? I wouldn't expect security cameras to be inoperative when they're needed most - at night!

Of course they have batteries.

[Cletus.D.Yokel]

:: Of course they have batteries. ::

Because that is what “solar” power is used for...maintaining a charge in batteries so the item can be used at night.
Or, on cloudy days.
Nothing runs directly from “solar power” since every passing cloud would cause it to shut down.