I should try to remember, next time I'm in a camping/fishing/disposals store, to get one of these.
To go with this, which I already carry on my pack. It's a US made 1Qt bottle; pretty much right on a litre capacity.
The bottle fits into the cup, and with the handles folded away, it all fits into the bottle cover.
I carry it half filled because half a litre's a convenient amount, it's not too heavy, so it doesn't weigh me down.
I could put the cup in the freezer for a couple of hours before I went out, then pop it on the bottle to keep the "fresh from the cold tap" water even colder. That's what MacGyver would do. 
Even clear plastic bottles have their uses.
Take the top from a solar garden light, make a hole in the bottle top for the LED to fit through, and glue it on.
Put the top/light out in the sun, during the day, to charge it up.
Two thirds fill the bottle with water and screw the top/light, onto the bottle.
And you have a clear plastic bottle solar powered lamp.
I've found a similar model solar garden light to the one shown being sold for $2 in a supermarket.
Parts, if you want to make one, aren't that hard to find.
Dumb question - have you tried fresh batteries?
Well, Duh...
Unfortunately, once they've shone their last, they've shone their last.
This is a fairly typical solar light circuit board.
See the little black things on the left? Semi circular case, flat front, three little wire legs?
One, or most likely both of those has gone on the blink.
While it's not the worst job in the world to remove and replace them, the cost of the replacement parts might exceed the cost of the light, itself.
In short, solar lights are not made to be repaired.
Of course, while you're moving the board around, trying to get the solder off the parts, and the parts off the board, Murphy's law states that one or more of those wires is going to come loose, and then you have the fun of trying to work out where it came from.
Electronics is the hobby for people with Infinite patience.
Close your eyes and say, three times, "I'm a shameless consumer..." and then go and buy some new ones. 
