Calculator Solar Cell

They are very low grade polycrystalline cells whose terminal efficiency is probably not much more than two percent long term.

A typical cell outputs 0.6 volts open circuit. Current depends on the incident light. As is the maximum power point.

In tracking bright sunlight, the incident power is 1000 watts per square meter or 100 milliwatts per square centimeter.

So two milliwatts in bright sunight, much less inside. Owing to tracking, intensity, and spectra. Minus the protective diode drop.

Ten stacks of ten cells might work.

A few larger and higher quality cells would probably be more effective.

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Many thanks,

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"James" schrieb im Newsbeitrag news: snipped-for-privacy@v45g2000cwv.googlegroups.com... | Hi All, | Thanks for the good responses to my previous post. | | I have a project that I am looking at that requires 1ma at 3V. I want | to see if I can use a calculator solar cell for charging the circuits | battery. I can not find any good information on calculator solar cells | on the web. It seems like they should be in volume production and not | to expensive. Anyone know what voltage the solar calculators run on? | Anyone know where to find information or data-sheets on calculator | solar cells?

Forget the calculator cells! If you have a lot of them on the desk it, works otherwise it is general an inefficient solution. Panasonic made them but stopped production, so you must buy in China today.

Use two or three ordinary solar cells made of cristalline silicone (the blue ones) in series and a switched-mode boost converter, e.g. one of the circuits to power LEDs. Google will help.

- Henry

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I am looking at the same sort of solutio path for a battery operate people sensor using a wirless outbound link for energy savings. The battery is critical as it enable installation of the sensor pod o the ceiling where the 'view" is better, alas not much line power there.

In the past we struggled to keep the 2-3 years on four aa alklines. Tis time we want to etxned the life >4 years.

The new cpus all like to work at 3.3 ot 2.6 volts so we use two cells. interacing with 3 volt logic to real world analog presents its own problems. Some technology is not there yet, relays etc.

Then we worked real hard to chop 10 ^13 eelctrons from each and every signasl path. then the next generation op amps 1-2 uA instead of

10u30uA. Then the snesor element itself consumed the most curent so it was trimmmed so that the sensor and the amplifier(s), and signal processor had eqaul currents. Then we have parts of the circuit tri-stated at time redcuing power dynamically, and finally once detetion takes place and is valid we latch a flip flop and turn the analog off.

The net is that we copnsume 60uW now down from 15 mW. Your calulator uses somthing like 10-50uA and that s what enables the solar power (tiny per cm^2) to be able to power a handhedl calculator.

I have a solar panel that stores inot a super cap, and I ahve it trickling power now. I plan to use Pulsed power techniguees to store and chrage..for a time.. and then dump inot a proper energy sore and re-chargin well. I can collect 200uA in diffuse room light. and can charge up in 142 seconds and this would run the unit (with a 1 volt depletion) for over 18 minutes. while useful you can only count on 6-8 hours of diffuse light. therfore I need to capture moe than i need to use in hours and trcikle it in over 16 hours, or tke the sow dissapation in the primary cell.

James, if you would like to keep the onversation going write direct to snipped-for-privacy@att.net Marc popek