Where no cabling is possible such as camp sites and rural areas then the use of solar lights is a must and are also a great use of light if you're on a budget and just want a simple solution to illuminate pathways, plantation areas and outside your home.  They act as a dusk to dawn light and some have Passive Infrared detection (PIR's) which activate when you are in proximity of them. Some also have an on off switch and remote-control functions too.  They are supplied with rechargeable batteries with the fittings and these should last approximately 2 - 3 years. Some of the Solar fairy lights are supplied with a portable USB device which means you can power the batteries from your computer or USB connection when the sun is very limited especially in winter. So provided they are installed preferably in a South Facing location and the panel gets lots of exposure to the sun they should work fine.