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Old April 12th 04, 08:11 AM
Roy Lewallen
 
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You've asked for a module that puts out 6-9 volts @ 100 mA. A more
accurate description of a solar panel would be that it puts out 100 mA
at 6-9 volts. Solar cells act a lot more like a current source than a
voltage source. So a panel that's rated at 100 mA at 12 volts will also
put out about 100 mA at 6 or 9 volts. (It'll be a bit more than 100 mA,
but not a whole lot more.) The open circuit voltage of a "12 volt" solar
panel (one intended to deliver current to a 12-14 volt load) will be
somewhere around 18 or 20 volts, and one specifically designed to work
at 6 volts will be about half that, 9 or 10 volts. So if you have a 6 -
9 volt device that you want to power with solar cells, you'll have to
float the panel across a battery, or use a voltage regulator to limit
the voltage. (A properly sized zener diode would be adequate for the
power level you're dealing with.) A 12 volt panel will be physically
larger than you need, but it might be easier to find and less expensive.

If you're looking for a module that includes a built in voltage
regulator to limit the voltage to 6 - 9 volts, you need to make it
clear. Most of the responses seem to be referring to 12 volt panels,
which will be fine if you limit the voltage, but won't be suitable if
you need voltage regulation to be included in the external module.

Roy Lewallen, W7EL

Bill Bowden wrote:

maxfoo wrote in message . ..

Anyone know of any solar cell vendors that sell
solar cell modules that put out 6-9volt @ 100mA?


TIA,



Lots of solar panels for sale on ebay. Here's a 12 volt 200mA
unit for 11 dollars.

Http://cgi.ebay.com/ws/eBayISAPI.dll...7173 830&rd=1


-Bill

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Old April 12th 04, 04:34 PM
 
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Hi;
I must say that this last responce was well writen and informitive, it
was a pleasure to read.

Thank you Mr. Lewallen


On Mon, 12 Apr 2004 00:11:36 -0700, Roy Lewallen
wrote:

You've asked for a module that puts out 6-9 volts @ 100 mA. A more
accurate description of a solar panel would be that it puts out 100 mA
at 6-9 volts. Solar cells act a lot more like a current source than a
voltage source. So a panel that's rated at 100 mA at 12 volts will also
put out about 100 mA at 6 or 9 volts. (It'll be a bit more than 100 mA,
but not a whole lot more.) The open circuit voltage of a "12 volt" solar
panel (one intended to deliver current to a 12-14 volt load) will be
somewhere around 18 or 20 volts, and one specifically designed to work
at 6 volts will be about half that, 9 or 10 volts. So if you have a 6 -
9 volt device that you want to power with solar cells, you'll have to
float the panel across a battery, or use a voltage regulator to limit
the voltage. (A properly sized zener diode would be adequate for the
power level you're dealing with.) A 12 volt panel will be physically
larger than you need, but it might be easier to find and less expensive.

If you're looking for a module that includes a built in voltage
regulator to limit the voltage to 6 - 9 volts, you need to make it
clear. Most of the responses seem to be referring to 12 volt panels,
which will be fine if you limit the voltage, but won't be suitable if
you need voltage regulation to be included in the external module.

Roy Lewallen, W7EL

Bill Bowden wrote:

maxfoo wrote in message . ..

Anyone know of any solar cell vendors that sell
solar cell modules that put out 6-9volt @ 100mA?


TIA,



Lots of solar panels for sale on ebay. Here's a 12 volt 200mA
unit for 11 dollars.

Http://cgi.ebay.com/ws/eBayISAPI.dll...7173 830&rd=1


-Bill


  #13   Report Post  
Old April 12th 04, 04:34 PM
 
Posts: n/a
Default

Hi;
I must say that this last responce was well writen and informitive, it
was a pleasure to read.

Thank you Mr. Lewallen


On Mon, 12 Apr 2004 00:11:36 -0700, Roy Lewallen
wrote:

You've asked for a module that puts out 6-9 volts @ 100 mA. A more
accurate description of a solar panel would be that it puts out 100 mA
at 6-9 volts. Solar cells act a lot more like a current source than a
voltage source. So a panel that's rated at 100 mA at 12 volts will also
put out about 100 mA at 6 or 9 volts. (It'll be a bit more than 100 mA,
but not a whole lot more.) The open circuit voltage of a "12 volt" solar
panel (one intended to deliver current to a 12-14 volt load) will be
somewhere around 18 or 20 volts, and one specifically designed to work
at 6 volts will be about half that, 9 or 10 volts. So if you have a 6 -
9 volt device that you want to power with solar cells, you'll have to
float the panel across a battery, or use a voltage regulator to limit
the voltage. (A properly sized zener diode would be adequate for the
power level you're dealing with.) A 12 volt panel will be physically
larger than you need, but it might be easier to find and less expensive.

If you're looking for a module that includes a built in voltage
regulator to limit the voltage to 6 - 9 volts, you need to make it
clear. Most of the responses seem to be referring to 12 volt panels,
which will be fine if you limit the voltage, but won't be suitable if
you need voltage regulation to be included in the external module.

Roy Lewallen, W7EL

Bill Bowden wrote:

maxfoo wrote in message . ..

Anyone know of any solar cell vendors that sell
solar cell modules that put out 6-9volt @ 100mA?


TIA,



Lots of solar panels for sale on ebay. Here's a 12 volt 200mA
unit for 11 dollars.

Http://cgi.ebay.com/ws/eBayISAPI.dll...7173 830&rd=1


-Bill


  #14   Report Post  
Old April 12th 04, 08:29 PM
maxfoo
 
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On Mon, 12 Apr 2004 00:11:36 -0700, Roy Lewallen wrote:

If you're looking for a module that includes a built in voltage
regulator to limit the voltage to 6 - 9 volts, you need to make it
clear. Most of the responses seem to be referring to 12 volt panels,
which will be fine if you limit the voltage, but won't be suitable if
you need voltage regulation to be included in the external module.


my pcb has a Linear Tech LT1117-5 LDO regulator on board, regulates 5volts with
a min input Voltage of 6 volts, so I'm currently using 4 AA batteries in a
battery pack with a 9v type clip. Wanted to be able to charge the batteries with
solar cells basically.

But after searching the web a bit it seems cheapest to buy individual cells
then tie them in series...No?

thanks,







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  #15   Report Post  
Old April 12th 04, 08:29 PM
maxfoo
 
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On Mon, 12 Apr 2004 00:11:36 -0700, Roy Lewallen wrote:

If you're looking for a module that includes a built in voltage
regulator to limit the voltage to 6 - 9 volts, you need to make it
clear. Most of the responses seem to be referring to 12 volt panels,
which will be fine if you limit the voltage, but won't be suitable if
you need voltage regulation to be included in the external module.


my pcb has a Linear Tech LT1117-5 LDO regulator on board, regulates 5volts with
a min input Voltage of 6 volts, so I'm currently using 4 AA batteries in a
battery pack with a 9v type clip. Wanted to be able to charge the batteries with
solar cells basically.

But after searching the web a bit it seems cheapest to buy individual cells
then tie them in series...No?

thanks,







Remove "HeadFromButt", before replying by email.


  #16   Report Post  
Old April 12th 04, 09:00 PM
Watson A.Name \Watt Sun - the Dark Remover\
 
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maxfoo wrote:

Anyone know of any solar cell vendors that sell
solar cell modules that put out 6-9volt @ 100mA?


Try All ELectronics. www.allcorp.com.

TIA,
Remove "HeadFromButt", before replying by email.

  #17   Report Post  
Old April 12th 04, 09:00 PM
Watson A.Name \Watt Sun - the Dark Remover\
 
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maxfoo wrote:

Anyone know of any solar cell vendors that sell
solar cell modules that put out 6-9volt @ 100mA?


Try All ELectronics. www.allcorp.com.

TIA,
Remove "HeadFromButt", before replying by email.

  #18   Report Post  
Old April 12th 04, 09:02 PM
Watson A.Name \Watt Sun - the Dark Remover\
 
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Joerg wrote:

Another option might be to use a different voltage panel,
whatever has a good price, and then use a small switcher to run
the cells at their optimum load.


Regards, Joerg.


Seems foolhardy to me, to use a boost circuit, and waste a lot of power.
Just put more PV cells in series to increase the voltage.

  #19   Report Post  
Old April 12th 04, 09:02 PM
Watson A.Name \Watt Sun - the Dark Remover\
 
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Joerg wrote:

Another option might be to use a different voltage panel,
whatever has a good price, and then use a small switcher to run
the cells at their optimum load.


Regards, Joerg.


Seems foolhardy to me, to use a boost circuit, and waste a lot of power.
Just put more PV cells in series to increase the voltage.

  #20   Report Post  
Old April 12th 04, 09:19 PM
Watson A.Name \Watt Sun - the Dark Remover\
 
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Roy Lewallen wrote:

You've asked for a module that puts out 6-9 volts @ 100 mA. A more
accurate description of a solar panel would be that it puts out 100 mA
at 6-9 volts.


Also the currewnt outputdepends somewhat on the latitude you're at. You
won't get all that current at the arctic circle.
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