The whole point about cheap systems is that you can buy more of them. And they do need maintenence (battery replace eventually) Think Cat's Eyes - dunno what the US calls them but they reflect car lights andf define the centre of the road and curvature. Buy enought of them you can define the entrance and the drive. Cheaper that digging concrete - (unless you have a really sharp spade **BG**)

I bought a snazzy little one that lights for 15 secs when you press it. Shaped to go round a barrel lock and illuminate the key hole. Only problem is on mine the handle is at the top and the key-hole was carved to take one of those barrels that go right through. Back to the drawing board.

FWIW NiCad and NiMH both loose charge carrying capacity as the temperature falls. As Joy found-out last winter. She is a gardener and listens to the radio as she works.