Do you have to ceremonially lay them out in the sun once a day? Once a week? Once a month?
What if it’s cloudy–do enough photons get through to recharge it?
Is ambient room light enough?
I’ve never owned one before, so I need to know.
Thank you in advance, whoever.
I haven’t owned one in a while but mine never took much at all. Ambient light is plenty and you can leave them in a drawer for months and they don’t seem to suffer much. I suspect the battery alone lasts for a long time. Even when it is using solar power, the requirements are minimal.
The solar calculators I have seen do not store much power at all. If you cover the solar cell the calculator dies almost immediately.
The solar calculators I have owned did not have a battery.
I guess some probably won’t, especially the older ones. Still, the light requirements aren’t that much.
Some solar calculators have a normal alkaline battery backup, but unless your calculator is real fancy, I doubt that the battery is rechargable. Usually the calculator draws power from the battery when there isn’t enough light, but when the battery runs out, it’s dead, Jim, and you just have to replace it.
You have specifically seen a battery in a solar calculator? Do you have a make on model for it? I have seen many solar calculators both old and new none of them had batteries.
Sure. You think somebody wouldn’t invent something as obvious as that? Feel-good energy saving measures that don’t actually accomplish anything are ever-popular.
Here is one example:
Battery backup has become pretty common, even on inexpensive calculators. I had a small (about the size of a deck of cards, but only a quarter inch thick) model that I picked up at a check out counter for less than a buck. It would operate easily in the cab of my truck at night w/ only the dome light. It lasted 4 to 5 years.
I’ve got an 8yr old, very basic solar calculator in front of me right now. It runs just fine inside, under a single florescent bulb, 10 ft above me. It works well if it’s in fairly heavy shadows (ie my monitor between it and light.) It also works with a couple of sheets of paper laying on top of it. So it doesn’t take very much light at all.
It does not have a battery, but if I do put it someplace dark enough to stop it from functioning, it will hold it’s single value memory, and the value on the screen.
Wow that is really lame. I have HP scientific calculators that I replace the batteries on every 4 or five years. If they were solar I would not have to replace the batteries for decades instead of years.
I was always under the impression that they made solar calculators because a tiny solar panel was cheaper than the battery plus the cost of making it easily replaceable.
I have both, a solar calculator with no battery and plenty with. I hate the one without, you can’t use it if the room is dim and you only have a lamp on, and I do plenty of stuff like that. The ones with batteries are way better IMO.
The last solar powered calculater that I had (15+ years ago) was impossible to use in direct sunlight; it had an LCD display that was unreadable under those conditions.
In regular room light, however, it was great.
In my experience, the solar panels degrade with age. A decent-quality new calculator will run in any light bright enough to read the display, but as it gets older, you’ll need brighter and brighter light. By the time my old TI was about 10 years old, you had to point a lamp directly at it to get reliable results, and at 13 years, even that wasn’t enough, so I had to retire it.
They do seem to be making progress on memory retention, though. My current calculator will sometimes retain the screen value and memory registers after being closed in its case and in my pocket for several hours (though of course it can’t actually be used in those circumstances).
I hear that solar caculators work best under direct, intense sunlight. In fact, the more intense, the faster they caculate. Perhaps this is why accountants have their conventions in Florida, Las Vegas and on Caribbean cruises.
So I don’t need to worry about laying it out in the sun periodically? Okay, thanks, that’s what I wanted to know. 
Well, it might melt under that hot Florida sun laying on that hot sandy beach.
