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Is it possible to use a garden light solar panel to power a wireless keyboard, without any use of batteries? Answered

I'm thinking of making an instructable on this. I know the voltage will be sufficient, but I don't know what current is given by the solar cells.


Josehf Murchison

7 years ago

Yes you should be able to power it if you get enough voltage and current.
For low voltage connect multiple cells in series.
For low current connect multiple cells parallel.
See my one watt solar array instructable.

333.bmp12 volt.jpgNone

9 years ago

If you know the voltage for your cells, you should also have the current(either measured, or from the spec sheet.)

To figure out if solar is acceptable for your keyboard... slap fresh batteries in it.
Use the keyboard till it starts giving you "low battery" symptoms.
Figure out how many mAh at what voltage got used.
Are your solar cells up to that task?

If no : FAIL

If Yes : Procede

At a minimum, you'll want a capacitor of proper capacity to "smooth out" the variable solar power. If you push all the way to Supercaps, you might actually get a few min of lights-out typing done. But at that level, they're almost batteries in their own right.

To give you an impression of how difficult this will be with solar cells smaller than your keyboard.... My wireless keyboard burns through a set of 5 AA batteries in 2 days of LIGHT use. Almost 1500mAh at 5volt(6 volt high, 5 volt cutoff) That's a MASSIVE solar cell, compared to my 108key keyboard size.
If your keyboard is lighter on power than mine, it MAY be a retrofitted USB keyboard. The keyboard circuit itself will probably run on 100mA, 5 volt. The wireless radio is another matter. If your willing to hack, or very very lucky, it may be under 500mA total, in which case, a cheap solar-usb charger SHOULD get the job done(google search says th3re's one for sale priced $17)


10 years ago

You do mean no non-rechargeable batteries because if you use power directly from the panels it can only be used in the direct sunlight.


Answer 10 years ago

The goal was to go battery free, of any type. If I put 2 cells in series, they put out about 2.6V under my desklight. But apparently that's not all that's needed :( Isn't there a way to juice these things up?


10 years ago

I'd advise you use solar to recharge the board, like Re. Low voltage / fluctuations are going to do funny things and frustrate you (you'll end up keeping a torch handy...)



10 years ago

I doubt if this would work. It takes almost all day of god sun to put enough charge to run some leds for a few hours. You might be able to charge it all day then use if for a few hours at night. But like jj37 said it needs bright sunlight to get much out of it.