Solar garden light designs, two problems

[al55]

Hi Guys,

I have a bit of a problem.

I have tried recreating these solar garden light designs:

http://talkingelectronics.com/projects/SolarLight/SolarLight.html circuit 1

http://www.members.shaw.ca/novotill/SolarGardenLight/index.htm circuit 1

using exactly the components they specify, a 1.2volt ni-cd battery and this solar panel:

http://www.futurlec.com/Solar_Cell.shtml sixth one (2v @ 45mA)

Unfortunately I have two problems:

1) I can’t get the circuit to switch off the LED as it always remains on. Which is because the solar panel does not produce enough voltage at low light levels to switch the first stage transistor on, turning the whole circuit off.

2) Also the battery does not charge! I leave the circuit in direct sunlight for 30min and then in a dark area and it lasts for less than a second. But when I attached a 4.5v panel the circuit works well.

I understand it’s the solar panel which is causing the troubles, but it is a 2v panel and that’s what the specs use. I have tried using IN5817 diodes with low Vf for better charging but still doesn’t work.

Is there anything that can be done with keeping the exact same solar panel??

Thanks.