In my installation, the solar panel was informed directly by the sun an hour a day. In the evening, the garland was working 2 to 3 hours in a row. I changed recently tinkering a extension cable to ten meters to put the solar panel to a better location. I took the opportunity to replace the battery (a mere 800ma battery ni-mh) by a 1700mA. So, now, the lighting works all night!
Note: In the manual mode, it is advisable to change the battery every 6 months.
I certainly would buy one when I need it!