Following a recent purchase of a $1 solar panel from eBay, I decided to try powering a graphing calculator with it. The 80x55 mm panel supposedly provides 1 watt at 6 volts. Here's the setup:
And here is the result:
I did use a partially broken TI-81 in case anything went wrong. Under direct sunlight, I was able to use the calculator with contrast setting of 2. The screen shut off as soon as I entered the shade, and the screen froze on whatever was last displayed when going back in the sun. Next to a 60 watt bulb, the display was on but extremely faint, and the calc did not power on under a 200 lumen LED.
Perhaps a TI-80 or a 3.3v calculator with a larger panel would fare better indoors, but I don't have any to test yet. I suppose that this would be more useful, though still unwieldy, if I can get it to run indoors.
And here is the result:
I did use a partially broken TI-81 in case anything went wrong. Under direct sunlight, I was able to use the calculator with contrast setting of 2. The screen shut off as soon as I entered the shade, and the screen froze on whatever was last displayed when going back in the sun. Next to a 60 watt bulb, the display was on but extremely faint, and the calc did not power on under a 200 lumen LED.
Perhaps a TI-80 or a 3.3v calculator with a larger panel would fare better indoors, but I don't have any to test yet. I suppose that this would be more useful, though still unwieldy, if I can get it to run indoors.