Why Apple Watch can't use solar Battery?

[Lennyvalentin]

Everybody's an expert in what cannot be done. That is why amazing things are created by such a small number of people.

Of course, none of what you just wrote is evidence it can be done. It's just empty words, whereas back in reality, we have, well, reality, to contend with.

We'd need power consumption reduction on the order of magnitudes to run a smartwatch on solar cells, especially as most of the time a wearer would be indoors under lamplight, which is literally tens, if not hundreds of thousands of times less radiant than sunlight.

Common sense tells us this is unlikely to actually ever happen, as it would require techological breakthroughs similar to those that took us from vacuum tube computers to modern day silicon semiconductors.

 

[Rok73]

It is more likely that battery technology aka the ability to save a lot more power in a small battery unit is making a huge step forward in the next couple of years.

 

[exxxviii]

Here is a very simple math way to look at this. It is not scientifically perfect, but it gives context and rough order of magnitude…

Demand: If the AW battery is 0.78 Wh, and the watch is rated for 18 hours, then the watch's average demand is about 43 mW.

Supply: If a moderate solar cell delivers about 10 watts per square foot, then that translates to 69 mW per square inch.

So, a 1 inch square solar cell could exceed the the average power demands of an AW. Couple that with a small battery to bridge the peak demands and periods without full light, and this is not a major gap to solve. They need to deal with a little miniaturization and screen design that could double as a solar cell. I think it is presumptuous to confidently state that Apple is not working on this or that the power demand is outrageous relative to the capacity of current solar technology.

 

[Bromeo]

The funny thing is the Apple Watch already has a solar panel mounted under the screen. This is possible due to how an OLED screen works. Light can pass through the gaps between the individual LED pixels, sort of like the opposite of a window screen. There is a tiny solar panel under the screen currently (no pun intended) that is used for sampling ambient light.

Apple's patent on this also includes the possibility to trickle-charge the battery. Don't know if that is the case currently with the Apple Watch.

 

[Lennyvalentin]

Here is a very simple math way to look at this. It is not scientifically perfect, but it gives context and rough order of magnitude…

This is a Glenn Beck-level take on solar cell-powered watches. 😛 None of what you write is probably wrong, per se, but it misses so much of the whole picture that in the end you're off literally by miles.

For starters, solar cell output depends greatly (ie, greatly) on the angle towards the sun. Unless you expect watch owners to stand in place with their arms stretched out from their bodies as not to cast a shadow over it and watches turned towards the sun for most daylight hours of the day, you're not going to come anywhere near your expected goal of captured energy. Most human beings would of course laugh at such a requirement as completely prepostrous, because it is.

Second, the best solar cells we have today are made from monocrystalline silicon wafers. They aren't transparent, so you'd have to confine the solar cell array to the bezel area of the watch, dramatically cutting down on potential energy captured. Bromeo above mentions the ambient light sensor above, but one has to take into account that the OLED display of the Watch has a black background (to improve black levels and thus, display contrast); this means any solar cell placed behind the screen would receive significantly less light than it would otherwise.

So if counting only best-case situation numbers, yeah, on paper this idea is feasible.

In reality; nope!

 

[firewood]

Supply: If a moderate solar cell delivers about 10 watts per square foot, then that translates to 69 mW per square inch.

... in direct sunlight. But many places are often cloudy during the day. When sunny, most people I know now avoid sun exposure of more than a few minutes a day for health reasons. Nor do they hold their wrists up, thus directed at the sky, very often, especially when outside in the sun. That's because the watch face is easier to read when not in direct sunlight. 4 strikes against.

 

[exxxviii]

In reality; nope!

You miss the point. Unless you are an Apple engineer, you do not have any knowledge of this, yet you are certain that it is outside of reality. And, you use a fringe ad hominem argument (i.e. "Glenn Bech") as an attempt to defend your opinion. Do you see the irony in "empty words?" I do not think you have provided enough fact to confidently state that it is impossible or Apple is definitely not working on it (unless Tim Cook told you that).

... in direct sunlight. But many places are often cloudy during the day. When sunny, most people I know now avoid sun exposure of more than a few minutes a day for health reasons. Nor do they hold their wrists up, thus directed at the sky, very often, especially when outside in the sun. That's because the watch face is easier to read when not in direct sunlight. 4 strikes against.

Solar cells generate energy under incandescent and fluorescent light. It is not as efficient, but they function. The point of this is that there is not a huge leap from current solar cell technology to a future when a watch could have a solar battery.

 

[Lennyvalentin]

You miss the point. Unless you are an Apple engineer, you do not have any knowledge of this, yet you are certain that it is outside of reality.

It's outside of reality, because it is. You can't rely on solar power to run your watch because of all the reasons I and others have already stated - more than once now, and especially not with a small battery to "bridge" as you suggest, because if you're not IN direct sunlight just for a couple hours, your watch would run out of power. You'd need a battery capable of a full day of runtime (or as Apple defines a full day, 18 hours 😛) for when it's dismal and rainy, or you live above the arctic circle in wintertime, or sit on a long-leg airplane trip, or, or, or, or...

And, you use a fringe ad hominem argument (i.e. "Glenn Bech") as an attempt to defend your opinion.

Invoking Glenn Beck was fully valid in this situation (and not actually an ad hominem; you may want to look up the expression in a dictionary) as you only mentioned best case scenario numbers and then fudged together the claim that your idea was completely feasible.

I do not think you have provided enough fact to confidently state that it is impossible or Apple is definitely not working on it (unless Tim Cook told you that).

Are you capable of logical deduction, man? I and others just gave you a bunch of reasons why solar powered watches don't work. Also, you don't see very many solar powered "smart" gadgets on the market, do you? Draw your own conclusions from that, if you are able.

Solar cells generate energy under incandescent and fluorescent light.

True, but as they aren't perpetual motion devices that create energy out of nothing, they will only convert a fraction of the light that actually hit them. A 20W CFL bulb may have a useful output of 2W actual light energy, the rest is waste heat. So 2W, AT THE BULB. (Note that the Watch draws about 2.5W peak charging from its wireless charger.) Now add inverse square law on top of that. Then add factors such as angle to light source (again), amount of light lost in reflections, solar cell efficiency (bad) and so on, and we're likely down to nanowatts. You can barely run a single LED on that kind of power. So you can forget getting anything approaching useful power output under indoor lighting conditions, unless all you're interested in running is a pocket calculator.

The point of this is that there is not a huge leap from current solar cell technology to a future when a watch could have a solar battery.

No, the real point is that you're wrong, unable to listen to reason and instead engaging in wild speculation and wishful thinking for god knows what reason.

Could Apple be working on a solar cell powered watch? Yeah, of course they could, they could be working on a time machine built out of a DeLorean too, but they'd never get anywhere with such a product because it's not a feasible or practical idea - for reasons already stated, which you have been unable to counter except by plugging your fingers in your ears.

 

[exxxviii]

It's outside of reality, because it is. You can't rely on solar power to run your watch because of all the reasons I and others have already stated - more than once now, and especially not with a small battery to "bridge" as you suggest, because if you're not IN direct sunlight just for a couple hours, your watch would run out of power. You'd need a battery capable of a full day of runtime (or as Apple defines a full day, 18 hours 😛) for when it's dismal and rainy, or you live above the arctic circle in wintertime, or sit on a long-leg airplane trip, or, or, or, or...


Invoking Glenn Beck was fully valid in this situation (and not actually an ad hominem; you may want to look up the expression in a dictionary) as you only mentioned best case scenario numbers and then fudged together the claim that your idea was completely feasible.


Are you capable of logical deduction, man? I and others just gave you a bunch of reasons why solar powered watches don't work. Also, you don't see very many solar powered "smart" gadgets on the market, do you? Draw your own conclusions from that, if you are able.


True, but as they aren't perpetual motion devices that create energy out of nothing, they will only convert a fraction of the light that actually hit them. A 20W CFL bulb may have a useful output of 2W actual light energy, the rest is waste heat. So 2W, AT THE BULB. (Note that the Watch draws about 2.5W peak charging from its wireless charger.) Now add inverse square law on top of that. Then add factors such as angle to light source (again), amount of light lost in reflections, solar cell efficiency (bad) and so on, and we're likely down to nanowatts. You can barely run a single LED on that kind of power. So you can forget getting anything approaching useful power output under indoor lighting conditions, unless all you're interested in running is a pocket calculator.


No, the real point is that you're wrong, unable to listen to reason and instead engaging in wild speculation and wishful thinking for god knows what reason.

Could Apple be working on a solar cell powered watch? Yeah, of course they could, they could be working on a time machine built out of a DeLorean too, but they'd never get anywhere with such a product because it's not a feasible or practical idea - for reasons already stated, which you have been unable to counter except by plugging your fingers in your ears.

I am not familiar with Glenn Beck, so it appeared to be an intended insult. I Googled "Glenn Beck Argument," and nothing jumped out at me to explain how that would apply as a counter to my illustration. You could have provided a similar mathematically-based counter-argument, and we could have debated the assumptions and factors, but you chose not to. Again, lots of data that argues that this would be difficult, especially for a lay person. I do not argue that with anyone. However, to extrapolate this to argue that Apple is not working on this or that it it is impossible is probably a reach. They have a patent (that you discarded as irrelevant) in this area. It seems they have invested some R&D and legal expense already.

Also, to say a couple times that I am wrong for saying it is possible that Apple is working on this is a tough defense, unless you have proprietary information from Apple.

 

[firewood]

Solar cells generate energy under incandescent and fluorescent light.

But not even close to enough (20 to 40 mW) to power a smartwatch in typical indoor lighting. If you can't even power the watch, the battery will run down, not get charged back up.

 

[JayLenochiniMac]

Extreme answers like "They're definitely not working on it and it'll never happen" and "They're most certainly working on it and it'll replace the battery as we know it" are almost always wrong. The Watch already has a power reserve mode, but it's not inconceivable that they're most likely working on an iPhone prototype with the solar panels built into the screen that could operate in a power reserve mode. Better to have a crippled iPhone than a completely dead one.

 

[Lennyvalentin]

I am not familiar with Glenn Beck

He is a man full of hot air and simpleton explanations to complex issues. Seemed perfectly analoguous to this situation.

I Googled "Glenn Beck Argument," and nothing jumped out at me to explain how that would apply as a counter to my illustration.

You've been told why your idea is unworkable. Repeatedly. People standing in the sun for hours to charge their watches, what planet are you from? *boggle*

You could have provided a similar mathematically-based counter-argument, and we could have debated the assumptions and factors, but you chose not to.

Your maths is entirely bogus. It relies on best-case numbers and from that you draw an absolutist conclusion that your idea is entirely within the realms of possibility.

However, to extrapolate this to argue that Apple is not working on this or that it it is impossible is probably a reach. They have a patent (that you discarded as irrelevant) in this area. It seems they have invested some R&D and legal expense already.

Companies file these types of patents as a matter of course, because if they don't then someone else will. It's no particular financial burden to them, comparatively speaking, so why wouldn't they. Companies like apple file (and receive!) patents that are obvious, or even completely impractical, by and large as defense against patent lawsuits. It is no clear indicator of future products, as many of these patents never end up in anything, like I said previously. The many drawbacks of putting solar cells in a wearable like a watch (or a phone for that matter) is enough to any person of sound judgment to conclude it would be pointless making it into a tangible product, because you would never be able to get enough power out of a solar cell on a watch or a phone to make it worth your expenses and the price increase for consumers.

Not without breakthrough innovations on the scale of orders of magnitude, which is currently beyond current human capability. I've been through this many times before. Your numbers rely on perfect conditions; full sunlight, right angles to the sun and so on and on. Who holds their watch like that? Nobody. Just because you can do a set of back-of-an-envelope calculations doesn't mean you suddenly cracked solar charging. If it was that easy we would have had it already!

Many great ideas look awesome on paper and not so well in reality. Like the comic sans font, for instance. 😉

 

[exxxviii]

Your maths is entirely bogus. It relies on best-case numbers and from that you draw an absolutist conclusion that your idea is entirely within the realms of possibility.

You are clearly very passionate about your opinion that a solar assisted battery in a watch is entirely impossible and Apple is definitely not working on it. That's OK.

 

[jasie02]

You need to wear one of this.

Or wear one of this if you are really proud of yourself.

Or drive one of this, to generate power anywhere close to what is needed to power AW.

 

[Night Spring]

You are clearly very passionate about your opinion that a solar assisted battery in a watch is entirely impossible and Apple is definitely not working on it. That's OK.

I think Apple is likely doing research on all sorts of battery technology, including the possibility of solar charging. But I also think we are years away, if ever, from being able to power mobile devices with solar power, and there is a possibility it can never be done. On the one hand, we are doing things today that many years ago people thought would never be done. But on the other hand, there are many things people thought would be solved by now that has yet to be figured out. So to say never is foolish, but solar powered mobile computing does seem to be impossible with current technology. It would require several fundamental breakthroughs to get there.

 

[Michael CM1]

Everybody's an expert in what cannot be done. That is why amazing things are created by such a small number of people.

I get what you're saying and applaud it. But I'm talking about what physically cannot be done with the technology we have now. It's not even close. It would be much smarter to develop huge solar farms with more efficient panels over time and then develop ways to retain more power in a watch battery and maybe charge wirelessly.

I think some research is being done into literal wireless charging, the type where your battery would absorb electrons from another source without these same electrons getting absorbed by you. It's not too far off from our wireless communications now except for you're talking electricity instead of microwaves.