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I think I've only seen two kinds of devices where an integrated solar panel actually made sense: calculators as their power draw is so low the one I bought almo

I think I've only seen two kinds of devices where an integrated solar panel actually made sense: calculators as their power draw is so low the one I bought almost 20 years ago for school still works with the original (non-rechargeable) battery. And more recently a GPS sports watch which can extend the battery life with solar for hours, or days when GPS isn't used. Other than that I agree, if you compare the power output to roof-mounted ones it seems quite pointless. Even relatively large, unwieldy USB charging panels you need to unfold can't hold up considering their area.

ajb 4y ago
Looks quite handy on a USB power bank: https://www.revk.uk/2022/09/battery-pack.html?m=1 https://www.revk.uk/2022/09/battery-pack.html?m=1 "Obviously these various battery packs were now all flat. One of the reasons for a battery back is for when you suddenly find you need portable power for something like this. All flat, except one! I can only assume it was getting enough light from my office lights, even in a clear plastic box, to actually stay charged." That is, not to charge the power bank (which would take ages) but to keep it charged during storage.
- yurishimo 4y ago
  I have one of these. It looks nearly identical but mine is green. I went motocamping for 3 weeks with somewhat limited access to electricity at times. I think my longest stretch was 3 days of camping with no access to plug in and recharge the pack. I was charging my iPhone 11, AirPods, and an Apple Watch. My phone was plugged into my motorcycle to charge/maintain while riding. The battery was positioned in a tank bag exposed to the sun for 8+ hours of riding per day. When I eventually used the battery's full capacity, any charge from the sun was basically useless until I was able to plug into line power again. I think after nearly a full day of riding after waking up to an empty battery, I might have gotten 3% on my phone when I stopped for the evening. When I returned home from the trip, I experimented with recharging the battery out on my apartment's veranda on the top floor with lots of sunlight all day. It took 3 or 4 days for the battery indicator light to move up 1 segment. Too long to be useful in any meaningful way. My point in all of this, is that these cheap "solar charging" battery banks are worthless unless you can live with waiting 2+ weeks to maybe charge your device. The panels are likely larger versions of the stuff used on calculators and should not be relied on. It's a marketing gimmick.
gruturo 4y ago
You reminded me of something I was considering years ago: screens have incredible resolution (DPI) now, and still growing. Some technologies are based on a backlight and a mask which blocks it in the right spots to form the picture (LCD, LED Backlight) while others actively emit the right colors at every location (OLED, MicroLED). At some point it would be pointless to keep increasing DPI due to being higher than any healthy person can resolve at a typical distance - but what if we do keep shrinking the emitting elements but arrange them more sparsely (same amount of pixels, but each one is super tiny) - and use the rest of the space for what is effectively a solar panel? Completely stupid, or did I think of something reasonable? I could see this as a benefit especially on phones, tablets and watches (maybe glasses, absorbing invisible frequencies). My usual beer clause applies: If anyone builds it successfully and makes millions with it, and this post ends up the earliest mention of the idea, you owe me a beer.

ajb 4y ago

Looks quite handy on a USB power bank: https://www.revk.uk/2022/09/battery-pack.html?m=1 https://www.revk.uk/2022/09/battery-pack.html?m=1 "Obviously these various battery packs were now all flat. One of the reasons for a battery back is for when you suddenly find you need portable power for something like this. All flat, except one! I can only assume it was getting enough light from my office lights, even in a clear plastic box, to actually stay charged." That is, not to charge the power bank (which would take ages) but to keep it charged during storage.

yurishimo 4y ago
I have one of these. It looks nearly identical but mine is green. I went motocamping for 3 weeks with somewhat limited access to electricity at times. I think my longest stretch was 3 days of camping with no access to plug in and recharge the pack. I was charging my iPhone 11, AirPods, and an Apple Watch. My phone was plugged into my motorcycle to charge/maintain while riding. The battery was positioned in a tank bag exposed to the sun for 8+ hours of riding per day. When I eventually used the battery's full capacity, any charge from the sun was basically useless until I was able to plug into line power again. I think after nearly a full day of riding after waking up to an empty battery, I might have gotten 3% on my phone when I stopped for the evening. When I returned home from the trip, I experimented with recharging the battery out on my apartment's veranda on the top floor with lots of sunlight all day. It took 3 or 4 days for the battery indicator light to move up 1 segment. Too long to be useful in any meaningful way. My point in all of this, is that these cheap "solar charging" battery banks are worthless unless you can live with waiting 2+ weeks to maybe charge your device. The panels are likely larger versions of the stuff used on calculators and should not be relied on. It's a marketing gimmick.

gruturo 4y ago

You reminded me of something I was considering years ago: screens have incredible resolution (DPI) now, and still growing. Some technologies are based on a backlight and a mask which blocks it in the right spots to form the picture (LCD, LED Backlight) while others actively emit the right colors at every location (OLED, MicroLED). At some point it would be pointless to keep increasing DPI due to being higher than any healthy person can resolve at a typical distance - but what if we do keep shrinking the emitting elements but arrange them more sparsely (same amount of pixels, but each one is super tiny) - and use the rest of the space for what is effectively a solar panel? Completely stupid, or did I think of something reasonable? I could see this as a benefit especially on phones, tablets and watches (maybe glasses, absorbing invisible frequencies). My usual beer clause applies: If anyone builds it successfully and makes millions with it, and this post ends up the earliest mention of the idea, you owe me a beer.