Products with solar cells

james merry Christmas & happy new year

ur idea is great, it can be used for any MP3 player, first of all you have keep in mind is all components use in compact MP3 player will working only at a certain temp if excess of heat is produce it may damage ur MP3 player, as well as your solar cell (short circuit) this why people don't use solar cell for audio player,

Try this

use ur solar cell to charge portables rechargeable batteries after the battery is fully charged use it in use MP3 player u will save electricity bill

At one point (probably 30 years ago) I convinced myself that all products would eventually use less energy/power, becomre more and more efficient, and solar cells would become more and more practicable.

But technology in the past few decades has completely bucked my predictions. Our computers use so much power and do so so wastefully that fans are needed for cooling, massive heatsinks on the processors, and we still don't do anything more useful with them than we did when they sucked less electricity.

OTOH battery technology has made advances and everything has some very dense power cell in it today, that has to be plugged into a recharger that draws several watts even when no power is needed at all!

The calculator hit the sweet spot - it's rare for folks to use LCD calculators in the dark, and the power required is pretty miniscule - and little else has.

All the personal portable devices of the past few years have a considerable peak power drain (requiring some sort of battery-type device) and might not ever see much sunlight.

So my prediction for the next 20 years is to assume lots and lots of tiny little devices that all suck lots of power. And I'm sure to be proven wrong again!

Tim.

I would imagine many mp3 players could run on 1mA. ....>

Unlikely! The audio amp alone would consume many times that, even for a headphone amp.

I'm not so sure on balance this is technically "correct". My experience with recharagable batteries is that you typically get no more than a couple hundred, to perhaps a few hundred honest re-charge cycles. And even then, many re-chargeable technologies DO NOT store the same number of milliamp-hours as the typical primary alkyline cell (which means you have to charge them more often.). Also, the chargers are not 100% efficient.

Plus, you have to expend energy just building the batteries (toxic stuff), which will on some level require environmental remediation (more costs...); they also charge and re-charge with fairly low efficiency, again requiring more cycles to obtain the equivalent mAh capacities over time (averaging here). And, you still have to replace the rechargeable batteries every so often (especially if they are abused, overcharged, etc..) They are also much more expensive initially, compared to a regular battery.

So while you may save a few pennies on the electric bill each month (if that?), those savings will be completely swamped by the cost of the rechargable batteries themselves, and probably by the utility bill though I did not calculate that.

I suspect solar powered MP3 players don't exist because consumers don't want them, the technology would be too bulky and cost effective to implement, and frankly, "economics". There are much better applications for solar power, and this is where you will find the investment dollars driving solar technology development. Not in MP3 players.

If you take one watthour as the lifetime actual use consumption of a typical calculator, your solar power source costs you around FIVE HUNDRED DOLLARS PER KILOWATT HOUR.

Few other apps have individuals overjoyed at paying these utility rates.

More at

I would guess that 98% of the time your walkman or phone is stuck in your pocket - unfortunatly I don't wear clingfilm all day and so my pockets are vastly in-effeciant at letting through light ;)

It's good idea though on paper - just not very practical.

One thing that could be useful would be something that charges the battery from movement - a bit like self-winding watches. Unfortunatly machanical parts like this are prone to break down in consumer goods and are also quite bulky :(

Brendan

On the other hand, if your calculator is powered by a 3-volt CR2032 coin cell battery with a capacity of 210 mAH, and a cost of about $3, that comes to a power rate of $4762 per KWHour. I would say that solar wins over batteries in that comparison.

Robert Scott Ypsilanti, Michigan

Not all - MP3 players are getting better - at the low end, 'only' using some 10-20mA off a 1.5V battery.

Assuming 1% conversion - dim light, and solar cell inefficiency, you need a solar cell 10cm or so in diameter. However, they've also gotten smaller.

Alkaline batteries (duracell) are only 2.8Ah or so. NiMH cells with a shelf life of 12 months, and a capacity of 2Ah are readily available now.

For full irony factor, the "solar calculators" at the dollar store have a completely non-functional solar cell on them. There's a small coin cell hidden behind the black plastic panel.

Tim.

Most calculators like that use the battery as a backup when there isn't enough light around... primarily because, yes, the solar cell is dirt cheap and thus kinda poor. But completely non-functional? That seems unlikely.

I remember the brief period in the '80s where the various name brands (Sharp, Casio, TI, etc.) really did compete on having good quality solar cells, telling you how their calculators only required a single candle's worth of light, etc. I would imagine these days all the quality brands do work fine in any light that most people would be comfortable in.

Well, they must use the vulcan mind-meld to transfer power out of that piece of black plastic, 'cause there ain't no wires!

I just googled "fake solar cell" and was met with numerous pages on the subject! Must be churning them out by the bazillions :-).

I've done some contracting for several companies that made solar cells over the past few decades. Economically a vary marginal industry was my conclusion. All the black aluminum dust everywhere inside the plant may have clouded my judgement! But certainly, making fake solar cells must be more economically viable than making working ones!

Tim.

Hmm... you're right:

While at a shop in Germany for a sandwich in the late 80's I saw a tray full of solar calculators next to the cash register. About $0.40 at that time and I couldn't resist because it had the size of a credit card, it fit right into my daytimer. Guess what, it's still in there and still works after 20 years so I guess there can't be a battery in it. A small task light is all it takes to make it work. However, I never figured out why it has an on/off button.

Another site:

Yes, but the fact remains that the OVERWHEMING MAJORITY of solar panel users are paying something like $500 per kilowatt hour for the privelege.

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I always wondered why there isn't any capacity rating on plain alkaline batteries. They must be closely matched.

SioL

My guess was always that it served as "reset" -- I've seen solar calculators "lock up" with bizarre displays due to being left in, e.g., very dim light and then taken to a bright room.

This one also has a separate clear button. It must contain a nifty brown-out circuit because this one doesn't hang. It just turns off. There is a hysteresis between turn on and off light levels.