Once the lights are fully charged they will run off that power and just recharge each day, depending on the weather and time of year depends on how long it will take for them to gain a full charge. You can leave the lights off for 3 days to ensure the build up base charge.
The operating time cannot be changed on the Bristols.
A full charge in the darkest part of winter is likely to take 3-5days. The light will charge just not be on for up to 10hrs unless fully charged
The spikes are plastic so will not rot.
Yes, you could extend yourself but it would void the warranty. The longer the wire from the panel to light/battery the more resistance and lower charge making it to the battery, but if the panel is in a far better location then this will outweigh the resistance.
60mm
IP44
Currently, we don't off extension cables for the Bristol lights. The cable is 1.2m away from the first light.
Diameter: 61mm