I fixed my solar garden light by draining the water, cleaning and drying the pcb, replacing the rusted away on-off switch with a jumper wire and replacing a shorted diode. The others I have glow for about 2 hours each night now in Autumn after charging all day (about 6 hours) in the sun.
But the one I fixed has a fully-charged 600mah Ni-Cad cell and it glowed all night and is still stong this morning when I shade it.
Therefore the solar panel has a very weak current now a days.