I think the 6v battery is dead, 6v made by Eagle Picher, Carefree. The
voltage measure 0.5. Do these rechargeable batteries get this low under
ordinary circumstances?
Really deep discharge, it's possible. I believe these are NiCad?
Try charging under bright sunlight for a day. Read the battery
voltage while it's charging, and see if it goes up. If not, there may
be a loose wire or bad connection somewhere. That seems to be a
problem with these outdoor lights.
You could always just try a new battery and see if it works.
Remember to recycle the battery when you buy a new one. If you buy
where you bought the lamp, Brinkmann guarantees they'll take it back
for recycling.
Good luck
Chris