I saw this cart last week at Roaring River Golf Course, just west of Belmopan:

http://www.flickr.com/photos/tranquilo/5312648043/

Paul, the owner, said they work great, but of course have a backup battery for cloudy days. I was curious if anyone has done this on Ambergris...?

Almost like magic. Everyone wants one.Was he sure that the cell made enough power to move more than a few minutes a day? My friends cart didn't and the cell is fragile. That is why these are not the only kind of cart in existence.
If this one is a practical self powered car it is going to win many awards and make someone rich.Special motor? New cell tech?Regenerative braking?

Sorry to be flip. You have a cool idea if it could be made to work.
The numbers tell all:
A cell used in this application is often the right physical size for 100 watts.That would make maybe 350 watt hours a day. A partially charged cart can be recharged with maybe 2500 watt hrs.
-The cart won't be able to drive around town with only the cell.
The amount of power the cell might make in a day would cost about US$0.15 cents. if you bought it from BEL.
Other numbers are also plausible but the relationships btween the numbers are the same.
The folks in my solar powered community on CC would all be driving them or just charging their carts from their home solar if it made enough juice.Instead they charge in town.
These cart tops have real benefits. Having 12 more minutes of creeping power at the end of some days can save you from a tow job.
Anything that keeps the cart battery slightly higher extends the batteries service life.

Dane,
Exactly how fragile are the tops?
Would a small coconut destroy it? Or a few almonds/seagrapes/belikin bottles etc.?
Would the top be a supplement source of power for, say, like a daily commute?
I would still have to use the charger in the night to get to work in the morning even if it sat in the sun all day?

Ditto!

There were a few on the island but their problem was that they took too long to fully charge the batteries. Here is an old thread on the subject: http://ambergriscaye.com/forum/ubbthreads.php/topics/290662/Solar_Golf_Carts.html I would be the first to buy when they are usable!

The cells vary in strength.A heavy one will withstand seagrapes but not cocos. If a guy leans in to speak to you with his hand on the top it will finally crack. This cuts the output but may not destroy the cell.The cell takes more than one day to charge a battery but can add enough in a day to be perceptible.
You can't park in the sun as often as you would like in a real life commute
You still need to charge every day.
New owners think they are getting more power than the same owner a year later as the wow effect is buried in too many tow jobs.

Me and Jan are probably the only guys here that could lean on a cart top. Sounds like it would take forever to pay for the thing savings wise, assuming it remains intact.
Sounds like an add-on for a rich tree hugger?
I will walk--need the exercise anyways.

Stumble?

Sometimes--lotta watering holes betwixt work and home.