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2009-07-27
, 13:46
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Posts: 398 |
Thanked: 301 times |
Joined on Sep 2007
@ Texas
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#2
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Well the wall wart is 5.0V. I've charged off of a USB port which is also supposed to be 5.0V.
I have a solar panel that puts out 5.0V but it does it in bursts, on for 2 seconds, off for 3 seconds and that just puts the tablet into a mode where the screen is always on and it's playing sounds for the start charge event and it ends up discharging the battery.
Frank
I have a solar panel that puts out 5.0V but it does it in bursts, on for 2 seconds, off for 3 seconds and that just puts the tablet into a mode where the screen is always on and it's playing sounds for the start charge event and it ends up discharging the battery.
Frank
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2009-07-27
, 14:05
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Posts: 1,390 |
Thanked: 642 times |
Joined on Nov 2007
@ California USA
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#3
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Originally Posted by Frank Banul
Skatebiker has the right idea, except I would use a solar panel that outputs 12 volts at full sunlight so that if it is somewhat cloudy it may still provide the 8.5 volts to the car charger. The 12 volt solar panel is very standard and used to keep a small charge on your car battery when parked for months at a time. For about $40 you can buy a 2.5 watt panel which will give you 200ma charge current.
Well the wall wart is 5.0V. I've charged off of a USB port which is also supposed to be 5.0V.
I have a solar panel that puts out 5.0V but it does it in bursts, on for 2 seconds, off for 3 seconds and that just puts the tablet into a mode where the screen is always on and it's playing sounds for the start charge event and it ends up discharging the battery.
Frank
__________________
N800 / Diablo / 16gb int / 16gb ext / Globalsat BT-359 gps ..... Dell Streak 5 - Android 2.2.2
N800 / Diablo / 16gb int / 16gb ext / Globalsat BT-359 gps ..... Dell Streak 5 - Android 2.2.2
Last edited by Den in USA; 2009-07-27 at 14:13.
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2009-07-27
, 16:00
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Posts: 542 |
Thanked: 117 times |
Joined on Sep 2008
@ 52 N, 6 E
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#4
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Originally Posted by Den in USA
No,the voltage is not dependant on cloudy or sunny sky. Mine outputs 8.5V @ full sunlight(500mA) or overcast sky (50mA).But many panels. output indeed 12 V.
Skatebiker has the right idea, except I would use a solar panel that outputs 12 volts at full sunlight so that if it is somewhat cloudy it may still provide the 8.5 volts to the car charger. The 12 volt solar panel is very standard and used to keep a small charge on your car battery when parked for months at a time. For about $40 you can buy a 2.5 watt panel which will give you 200ma charge current.
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2009-07-27
, 16:15
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Posts: 1,390 |
Thanked: 642 times |
Joined on Nov 2007
@ California USA
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#5
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Originally Posted by skatebiker
Skatebiker, sorry I got confused. Solar panels contain "cells" that are wired in series to abtain the needed voltage. That voltage changes according to the amount of sunlight. Apparently the panels today contain voltage regulators such as yours. In the old days we had to add external regulators.
No,the voltage is not dependant on cloudy or sunny sky. Mine outputs 8.5V @ full sunlight(500mA) or overcast sky (50mA).But many panels. output indeed 12 V.
__________________
N800 / Diablo / 16gb int / 16gb ext / Globalsat BT-359 gps ..... Dell Streak 5 - Android 2.2.2
N800 / Diablo / 16gb int / 16gb ext / Globalsat BT-359 gps ..... Dell Streak 5 - Android 2.2.2
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2009-07-27
, 16:45
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Posts: 1,562 |
Thanked: 349 times |
Joined on Jun 2008
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#6
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What you need is a solar charger with a "smart power controller". IE, no matter what voltage or amperage the cells are putting out, the unit always outputs the designed voltage and amperage. With the NITs, they need a steady voltage of either 12v, or 5v, and a minimum 400ma current to ensure charging. 800ma if you're doing something under load so that it doesn't start hitting the battery.
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Popular Sci-Fi author and creator of the Earthfleet Series.
www.realmsofimagination.net
Popular Sci-Fi author and creator of the Earthfleet Series.
www.realmsofimagination.net
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2009-07-27
, 17:01
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Posts: 45 |
Thanked: 17 times |
Joined on Nov 2008
@ Montreal, Canada
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#7
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Anyone playing with non-standard charging should read this:
http://sw.nokia.com/id/3378ff2b-4016...on_v1_2_en.pdf
Anyways, the standard charger does not give 5V, it's more like 8V or so, less under load. Voltage should never exceed 9.3V according to that spec, in the N800, you'll risk tripping the built-in zener diode and then blowing the 2A fuse. I guess if a solar panel can't supply more than 500mA, it should be safe, just make sure there isn't a capacitor in line that could supply a short-duration high-current spike.
If the input voltage is around 5V, the N800 will see it as a "special" charger and never actually fully charge the battery. AFAIK, LiPol batteries are not very efficient to charge the last 20%, so it's better to just keep it at that level unless you have plenty cheap power available (that is, a wall charger), and can afford to turn most of it into heat.
http://sw.nokia.com/id/3378ff2b-4016...on_v1_2_en.pdf
Anyways, the standard charger does not give 5V, it's more like 8V or so, less under load. Voltage should never exceed 9.3V according to that spec, in the N800, you'll risk tripping the built-in zener diode and then blowing the 2A fuse. I guess if a solar panel can't supply more than 500mA, it should be safe, just make sure there isn't a capacitor in line that could supply a short-duration high-current spike.
If the input voltage is around 5V, the N800 will see it as a "special" charger and never actually fully charge the battery. AFAIK, LiPol batteries are not very efficient to charge the last 20%, so it's better to just keep it at that level unless you have plenty cheap power available (that is, a wall charger), and can afford to turn most of it into heat.
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2009-07-27
, 17:33
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Posts: 398 |
Thanked: 301 times |
Joined on Sep 2007
@ Texas
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#8
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Well that explains a lot to me. I'm kind of annoyed that the wall charger is marked as 5V though since that is clearly not the case. But to their credit, the pdf is awesome, I wish other manufacturers provided this type of information.
Frank
Frank
Originally Posted by jthiemann
If the input voltage is around 5V, the N800 will see it as a "special" charger and never actually fully charge the battery. AFAIK, LiPol batteries are not very efficient to charge the last 20%, so it's better to just keep it at that level unless you have plenty cheap power available (that is, a wall charger), and can afford to turn most of it into heat.
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2009-07-27
, 17:36
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Posts: 542 |
Thanked: 117 times |
Joined on Sep 2008
@ 52 N, 6 E
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#9
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Originally Posted by Den in USA
Each crystalline silicon cell is 0.45 V but the voltage does NOT change much dependant on sunlight. See the diagrams here:
Skatebiker, sorry I got confused. Solar panels contain "cells" that are wired in series to abtain the needed voltage. That voltage changes according to the amount of sunlight. Apparently the panels today contain voltage regulators such as yours. In the old days we had to add external regulators.
http://en.wikipedia.org/wiki/Solar_c...ircuit_current
which confirm my measurements. Measuring the voltage of my small panel (loaded) it measures 8.4 V in full sunlight and 8.1 V in overcast sky. It contains of 18 cells in series which makes 18*0.45 = 8.1 V.
Here a picture of the panel :
BTW, DealExtreme sells 6 V 200mA (maybe 5.4 V as they have 12 cells according to the image)
http://www.dealextreme.com/details.dx/sku.18168
for only $17 which can be switches parallel and be used as a USB or Nokia charger.
Last edited by skatebiker; 2009-07-27 at 17:38.
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2009-07-27
, 18:11
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Posts: 900 |
Thanked: 273 times |
Joined on Aug 2008
@ Fresno CA USA
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#10
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I've a wall wart for the nokia battery. The label says Output DC 4.2V 350mA. I get a full charge with it.
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George Fragos
Internet Coach & Writer
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N810 -- 5.2010.33-1
George Fragos
Internet Coach & Writer
Maemo Mapper HowTo
Personal Blog -- 3 Joe's Blog
N810 -- 5.2010.33-1
Using a 8.3 volts solar panel connected via a car charger does charge.
Using the same panel without car charger (i.e. the 8.3 volts directly to the N810) displays 'Not charging', which I think 8.3 volts is too high.
But when I put a single diode in series (0.7V volrage drop) does charge the N810 (and my 5800 XM phone).
Measuring the charge currents was in all cases 200-230 mA (battery was nearly full, all but one blocks in the battery icon was filled).
Does someone have experiences with charging voltages / alternative charge sources?