we advise our customer to position it south-facing while switched off as it will need sunlight to charge however we do have batteries in our lights that help the solar panel charge when there's a dull day where your not getting sunlight
The lights will need direct daylight in order to charge. If the weather is not great that might affect the run time.
We do not have a decking light with a screw thread at the back. However, these lights can possible work:
https://www.thesolarcentre.co.uk/products/Sherpa_Solar_Step_Lights_Set_Of_4-863-56.html
You can take off the spike if you wish to.
These are a white colour.
I would not recommend installing them so that the panel is not facing up and receiving direct sunlight.
These lights can be installed with a spike.
They come with a spike so it might not be suitable for artificial grass.
The stake would be used for the grass only.
The lights come with a spike for easy installation.
These lights come with a spike.
Yes, these are on spikes, so would work, just make sure the foliage does not cover the panels.