HackModford
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Solar Charger I Found
- Thread starter HackModford
- Start date
"1000mAh Li-ion battery"
That is: it's internal battery is 1/4 of the Pandora's one.
That means you will get 12.5 hours instead of 10 (probably will end up being 11.5 instead of 9.5).
So:
-provided you have 8 hours of sun to charge completely the internal battery,
-provided you actually have a place where to put the charger,
you will probably get 2 (or less) "free energy" hours of pandora use per-day.
But you could actually glue it to the Pandora so this might become a nice idea
That is: it's internal battery is 1/4 of the Pandora's one.
That means you will get 12.5 hours instead of 10 (probably will end up being 11.5 instead of 9.5).
So:
-provided you have 8 hours of sun to charge completely the internal battery,
-provided you actually have a place where to put the charger,
you will probably get 2 (or less) "free energy" hours of pandora use per-day.
But you could actually glue it to the Pandora so this might become a nice idea
benjymous
Member
HackModford said:
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craigix
Mega GP Mania
We did look in to putting a solar 'coat' on the Pandora... for about 20 minutes.
Essentially it would take about a week to get a decent charge and would thicken the unit out a lot more.
OK if you don't plan to use it much
Essentially it would take about a week to get a decent charge and would thicken the unit out a lot more.
OK if you don't plan to use it much
HackModford
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Then your best bet is too just build your own right? I'm more interested in "charging" than running of a battery...
Butterman
Gief Pandara
I've got something similar, when I take my phone on a long boat cruise or camping I charge it with something like this, used to do a mighty fine job of charging my PSP too.
benjymous
Member
It's nothing particularly specific to that device - basically solar panels are hideously inefficient - only a tiny fraction of the light energy that hits them gets turned into electricity. You could give a Pandora a good charge with the sort of large roof mountable panels that cost thousands, but any panel small enough to carry around (or just carry!) isn't going to produce enough current to charge at any sensible speed (as Craig said, a good week or so to get a decent charge)HackModford said:
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j.pickens
Member
Based upon the photos, looks to be about 8 sq. inches of solar panel.
If its a real good panel, it will get approx. 12% efficiency in clear noon sunlight.
Clear noon sunlight is approx. 100 W/sq. ft.
8 in. sq. = 8/144 = 0.06 sq. ft.
100W X 0.12 X 0.06 = 0.7 W
If you have four hours of real good sunlight, and place it in it, you'll get:
0.7W X 4 hours = 2.1 Watt hours.
For a 1100mAh battery at 5.5V, you need:
1100mAh / 5.5V = 200 watts for one hour (or equivalent) to fully charge it.
In the real world, you'd use a Li ion charger for five or six hours at 50 watts load to charge it.
If you use usb, then at the 500mA normal USB limit, it would take 2.1 hours at balls to the wall
maximum usb load to fully charge a fully discharged 1100mAh battery.
Again, in reality, it would take four or five hours to top up a 70% discharged battery with usb.
At 2.1 Watt hours in one day, you'd need 100 days to fully charge the battery in this solar charger.
The product is bullshit.
You need more solar panel area to get enough energy to charge a battery like this.
If you want to fully charge an 1100mAh battery in one average day of real good sunlight, you'd need a panel 100 times bigger.
Or, 800 square inches, roughly Seven square feet.
Something like this:
http://www.siliconsolar.com/shop/solarimag...rger-15W_D5.jpg
If its a real good panel, it will get approx. 12% efficiency in clear noon sunlight.
Clear noon sunlight is approx. 100 W/sq. ft.
8 in. sq. = 8/144 = 0.06 sq. ft.
100W X 0.12 X 0.06 = 0.7 W
If you have four hours of real good sunlight, and place it in it, you'll get:
0.7W X 4 hours = 2.1 Watt hours.
For a 1100mAh battery at 5.5V, you need:
1100mAh / 5.5V = 200 watts for one hour (or equivalent) to fully charge it.
In the real world, you'd use a Li ion charger for five or six hours at 50 watts load to charge it.
If you use usb, then at the 500mA normal USB limit, it would take 2.1 hours at balls to the wall
maximum usb load to fully charge a fully discharged 1100mAh battery.
Again, in reality, it would take four or five hours to top up a 70% discharged battery with usb.
At 2.1 Watt hours in one day, you'd need 100 days to fully charge the battery in this solar charger.
The product is bullshit.
You need more solar panel area to get enough energy to charge a battery like this.
If you want to fully charge an 1100mAh battery in one average day of real good sunlight, you'd need a panel 100 times bigger.
Or, 800 square inches, roughly Seven square feet.
Something like this:
http://www.siliconsolar.com/shop/solarimag...rger-15W_D5.jpg
benjymous
Member
Thanks - I'm far too tired to work out the maths myselfj.pickens said:
All I can say is I've never been satisfied with any solar panel I've ever bought - small ones are only any use to powering things like pocket calculators that really don't need a huge amount of power in the first place!
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Butterman
Gief Pandara
j.pickens said:If you want to fully charge an 1100mAh battery in one average day of real good sunlight, you'd need a panel 100 times bigger.
Or, 800 square inches, roughly Seven square feet.
Something like this:
http://www.siliconsolar.com/shop/solarimag...rger-15W_D5.jpg
Well, mine was about 1 sq ft when folded out, it was quite expensive too.
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christo930
Well-Known Member
HackModford said:What do you think? This would come in handy in the inevitable economic breakdown right?
Walmart sells a solar powered auto cooler that uses pretty good quality glass solar panel to turn a pretty strong fan and it's $17 and creates more power than this $50 thing. You can also pick up a trickle charger at pepboys for 69.99 that puts out about 17 watts in full sun. It's bigger but size matters. If you charge it up during the day, you can run it at night for free. Just use a cigarette lighter adapter and you can charge your pandora in a few hours. If you really look around and are willing to put some thought into it, you can find some good ideas.
Of course, if you are worried about an economic breakdown (which I am), the Pandora is going to be the least of your concerns.
Chris
j.pickens said:Based upon the photos, looks to be about 8 sq. inches of solar panel.
If its a real good panel, it will get approx. 12% efficiency in clear noon sunlight.
Clear noon sunlight is approx. 100 W/sq. ft.
8 in. sq. = 8/144 = 0.06 sq. ft.
100W X 0.12 X 0.06 = 0.7 W
If you have four hours of real good sunlight, and place it in it, you'll get:
0.7W X 4 hours = 2.1 Watt hours.
For a 1100mAh battery at 5.5V, you need:
1100mAh / 5.5V = 200 watts for one hour (or equivalent) to fully charge it.
In the real world, you'd use a Li ion charger for five or six hours at 50 watts load to charge it.
If you use usb, then at the 500mA normal USB limit, it would take 2.1 hours at balls to the wall
maximum usb load to fully charge a fully discharged 1100mAh battery.
Again, in reality, it would take four or five hours to top up a 70% discharged battery with usb.
At 2.1 Watt hours in one day, you'd need 100 days to fully charge the battery in this solar charger.
The product is bullshit.
You need more solar panel area to get enough energy to charge a battery like this.
If you want to fully charge an 1100mAh battery in one average day of real good sunlight, you'd need a panel 100 times bigger.
Or, 800 square inches, roughly Seven square feet.
Something like this:
http://www.siliconsolar.com/shop/solarimag...rger-15W_D5.jpg
Your math is faulty. You do not need 200 watts to charge a 5.5v 1100mah battery. That is 6.05 watt hours. Given the inefficiency of batteries as they get closer and closer to 100% charged, you might need 10watt hours to charge it.
Chris
Butterman said:j.pickens said:If you want to fully charge an 1100mAh battery in one average day of real good sunlight, you'd need a panel 100 times bigger.
Or, 800 square inches, roughly Seven square feet.
Something like this:
http://www.siliconsolar.com/shop/solarimag...rger-15W_D5.jpg
Well, mine was about 1 sq ft when folded out, it was quite expensive too.
a 7 square ft solar panel should have NO PROBLEM charging a pandora battery. I've seen 50 watt solar panels about that size. Photovoltaics is not terribly efficient, but it's not that bad. Small solar panels ON MARS are creating 700+ watts in a fairly short Martial sol, receiving 1/2 the sunlight.
Chris
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Forget about solar. Use those kinetic mechanisms that are in watches. I would guess that if you put enough of those, you might have enough energy for minimal things.
I no, I no, too heavy too expensive, and probably not gonna work. But a man can dream can't he?
I no, I no, too heavy too expensive, and probably not gonna work. But a man can dream can't he?
j.pickens
Member
Oops, the mA to A conversion screwed me up.christo930 said:
But even so, my Wh calculation was correct.
So, instead of 100 days to charge it up, it would be more like 5 days, using your 10 Wh value.
Still, a steaming pile of false hope in that solar battery "charger".
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psychodegu
Still Fresh
- Joined
- Sep 23, 2008
- Messages
- 41
5 days huh, seems craig's estimation that it would take a week to power the sucker, was pretty spot on. Which is like 1.5 hours of use each day on average.
riosingh
Member
what you need is.
one of these
http://www.maplin.co.uk/module.aspx?moduleno=223250
and a car battery.
and a psp car charger.
Job done
one of these
http://www.maplin.co.uk/module.aspx?moduleno=223250
and a car battery.
and a psp car charger.
Job done
Polossatik
I reject your reality and substitute my own
I also looked into this a time ago in this thread.
Might have some usefull info.
Once my bank balance is back to normal (damn holliday's ) i'll order some panels ...
Might have some usefull info.
Once my bank balance is back to normal (damn holliday's
) i'll order some panels ...
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I've been using the Solio: http://www.solio.com/charger/
It takes about 2 days of decent sun to charge. Once charged, it can charge up my iPod almost 2 full charges. So for the iPod, it's not bad at all.
I'm not getting any unrealistic expectations about it charging the pandora. I'll just have to wait until it arrives before I can experiment.
It takes about 2 days of decent sun to charge. Once charged, it can charge up my iPod almost 2 full charges. So for the iPod, it's not bad at all.
I'm not getting any unrealistic expectations about it charging the pandora. I'll just have to wait until it arrives before I can experiment.
Monk
Caveman Ninja
I have something like this:
http://www.maplin.co.uk/Module.aspx?ModuleNo=99760
Though mine is supposedly a 28W not 13W one from eBay (so probably only REALLY 3 Amp - I've never gone to the effort of trying to measure how well it does. I'm in the UK - we don't know what The Sun is anyway unless it's a tabloid newspaper).
but surely, this is a homebrew kinda community... shouldn't we be looking at something like:
http://www.shinyshiny.tv/2007/09/make_your_own_s.html
?
http://www.maplin.co.uk/Module.aspx?ModuleNo=99760
Though mine is supposedly a 28W not 13W one from eBay (so probably only REALLY 3 Amp - I've never gone to the effort of trying to measure how well it does. I'm in the UK - we don't know what The Sun is anyway unless it's a tabloid newspaper).
but surely, this is a homebrew kinda community... shouldn't we be looking at something like:
http://www.shinyshiny.tv/2007/09/make_your_own_s.html
?
If you were to being living somewhere hot and could make do with one of these, I wouldn't want my pandora sat in roasting hot weather in direct sunlight.
Unless i was on a small boat, I can't imagine there is many people that can't get to a wall socket or USB port every couple of days. And given that we've got the best part of 10 hours (maybe more) battery life, i don't think it's a viable options.
Unless i was on a small boat, I can't imagine there is many people that can't get to a wall socket or USB port every couple of days. And given that we've got the best part of 10 hours (maybe more) battery life, i don't think it's a viable options.
