Unexpected observation

Options
D_A_N
D_A_N Registered Users Posts: 8 ✭
in Solar Beginners Corner #1
I have some very inexpensive solar landscape lights. The solar cell is about 2x2 inches, they have one LED and 3 AA NiCad batteries. They charge when they can and when it's dark they stay lit until dawn or the charge runs out. They are low enough efficiency that on many overcast days they don't charge enough for the lights to even come on.

A few days ago a storm came through and coated everything with ice and then snow. The days since have been very clear all day long.

Last night and again tonight the lights are all lit up. Yesterday they came on about 5 and were still bright at Midnight when I went to asleep, that's 7 hours.

The lights have between 1/4 to 1/2 inch of ice and 2 inches of snow covering the solar cells. I realize some light will penetrate 2 inches of snow and even the ice, but I figured with the short winter days, the low efficiency and the cells covered that they wouldn't work.

Has anyone had any experience like this?
· Share on Twitter

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Options
    Re: Unexpected observation

    your guess is as good as mine for all kinds of weird things happen with these cheap things. i just took mine out due to the batteries being discharged too far so i charged them on my aa charger. the charger indicated they weren't any good anymore so i threw a slightly higher rated nicd in its place and it failed to do anything at all. the original nicds were 350ma and i place one in there to see if it acted any better. the led started blinking on/off at 2 sec intervals. i then hit the front of it with my flashlight beam and it started working properly thereafter.
    a guess may be the ice/snow acted as a lens and concentrated the solar at some point and solar cells will deliver a bit more power when cold too.
    · Share on Twitter
  • Shadowcatcher
    Shadowcatcher Solar Expert Posts: 228 ✭✭✭
    #3
    Options
    Re: Unexpected observation

    I replaced the Ni-cad's with Ni-mh batteries (do not form a memory as do Ni-cad's). I have a Maha charger that seems to be one of the best and will cycle Nicads and slow charge each cell independently.
    Since deep cycle batteries benefit from cold in charging...?
    · Share on Twitter
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
    Options
    Re: Unexpected observation

    if memory serves nimh do not function very well in the cold compared to nicd. it is cheaper to actually buy another whole solar light than to put a nimh in it. if you were in my area i'd give you a nicd, but even with the cost of gas the way it is it would only be worthwhile to pick it up if you were within a few miles of me.:roll:
    · Share on Twitter

Categories