Absences electronic interventions in nature

Found some very nice garden lamps at a local store. They're pretty cheap (2.50 CAD each), they're small but they look robust. I opened them. The circuit looks very simple, I actually still don't understand how the LED is switched on during the night and off during daylight.

Here are the specs that I measured for the solar panel (under a 100 Watt lightbulb): max. 2.96V @ 2.92mA. So the amperage is very low but the voltage is actually not bad. The resulting price per Watt is very high, close to 280 CAD, where the lowest I can get is around 5 CAD/Watt (!) So, yeah, it's pretty bad, but you get more than just the solar panel, you get the small circuit, the battery (1.2V/350mA NiCd) and the waterproof enclosure.

I bought ten of those. If we put them 3 by 3 ie. groups of three in series we get a max output voltage of 9V. We can then put 3 groups of 3 in parallel for a (very low) output current of 9mA.