two 9v solar panels

Discussion in 'The Projects Forum' started by toolofdoom, Apr 21, 2012.

  1. toolofdoom

    Thread Starter New Member

    Apr 21, 2012
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    Hello everyone just got me two solar panels at 9v and .5 watt with some plugs for a few rechargables to which i can get any kind but i need some assist i find some circuits online but none are close enouph to take pieces from. What my goal is is to have these 2 panels charge my 9v battery pack this will be used to connect to a few usb ports say 3 at least and so that way i can charge a phone or something plugged into the usb female connectoins to which i also have i know these are 5v and so i bought a whole pack of many resistors with a tm317 variable resistor i think im missing a diode so that the charge doesnt reverse to the panels and something to stop from over charging though i dont know if this would happen being there also 9v panels these should be hooked in series yes?
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Before you go much farther, you should consider the end result. A typical USB device charges at 100mA or more, some devices draw as much as 1A. That's a range of 0.5W to 5W. So your solar cells will have a tough time getting ahead to give you a full charge in a reasonable time (eg. a full day of full sun). Charging a battery for later power is about 50% efficient. And then converting your battery power to 5V regulated power for USB is going to be 80-90% efficient, but only by using a rather complex circuit. The "simple" solution - a 7805 voltage regulator - is going to waste about 40% of everything coming out of your 9v battery.
    So, you CAN do what you want, but it's not going to be as simple as you might like and, IMHO, is going to be disappointing in the end. You either need more solar cell power or lower expectations.
     
  3. toolofdoom

    Thread Starter New Member

    Apr 21, 2012
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    Ya know you mis understood I was asking someone that knew something you could have summed all that up two here's how you do it but add in 2 more chips but I can tell by your response you know nothing your just here to give people ****. I don't much care for your answer either way! :eek:
     
  4. toolofdoom

    Thread Starter New Member

    Apr 21, 2012
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    Anyone else a little more optimistic and positive perhaps lol
     
  5. evilclem

    Member

    Dec 20, 2011
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    Are you asking if the 9V panels should be hooked in series? Not for a 9V battery, the panel rating is 9V and the actual voltage will be higher. You also WILL need charge regulation to avoid cooking the battery.

    You also need to learn how to take all advice given to you regardless on whether it is positive or negative. You should also add some grammar or many will simply ignore you.
     
  6. MrChips

    Moderator

    Oct 2, 2009
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    You get what you asked for. toolofdoom should be renamed manofdoom.
     
  7. toolofdoom

    Thread Starter New Member

    Apr 21, 2012
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    Foget I even came to you retards for advice alls you can do is state the obvious and poke fun at the ? Asked instead of answering with what you know oh wait you did answer with what you know... Nothing I came thinking some of you might actually be able to make a working schematic I can tell you all grab bits and pics from others work none of you know what the hell your talking about and I can't help but comment on the Manofdoom omg really dude! Really? You really enjoyed the short bus huh! I'll post MY working schematic for all of you when I'm done.
     
  8. Mark_T

    Member

    Feb 7, 2012
    47
    8
    This schmatic i must see! Weyneh was only stating some physical facts, they can't just be ignored. you can only take out less than is put in. But good luck in charging one phone slowly its greener than using mains.
     
  9. MrChips

    Moderator

    Oct 2, 2009
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    This forum manages quite well thank you without people with no manners and respect.
     
  10. toolofdoom

    Thread Starter New Member

    Apr 21, 2012
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    I will show you the working schematic no problem
    I'm still stuck on what an idiot you are chips I ask a ? You answer with an insult to my handle lol and I'm the one with no Manners or respect ok! Well then your the ridiculous delusional one with no social life and no friends, also you claim to know things about **** you know nothing about. You insult yourself!
     
  11. MrChips

    Moderator

    Oct 2, 2009
    12,449
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    Let's look at the facts.
    You post #1 looking for some help.
    An experienced member gives you sound advice in post #2.
    You respond in post #3 showing disrespect for his advice.
    Well as I said, you get what you ask for.
     
  12. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,795
    950
    You could take the advice offered, OR

    You could connect the panels in whatever way you wish, and after struggling to achieve your hoped for results, you could come back here and present your findings.

    Then we can compare and contrast the results with the pro-offered advice to see if your opinion of it was correct, or if the advice was correct.

    I personally would take any advice I was given by an expert in a field I was only passingly conversant in.
     
  13. wayneh

    Expert

    Sep 9, 2010
    12,145
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    Many solar chargers have a panel that delivers a no-load voltage about double the battery voltage. In theory that's a higher than optimal voltage, but it covers the drop across the blocking diode and allows charging in less-than-full light. I'd guess the designers studied how to get more mAh stored in a day, and this was the result.

    So put the 2 panels in series with the blocking diode. That's the minimal arrangement. Your panels may be small enough to not ruin - by overcharging - your battery pack but we can't tell from the details offered so far. To protect your battery, you'll likely need a circuit to dump excess current. I've posted solar light circuits with an example of this that would work fine.

    The best way to get USB power would be to use a DC-DC converter IC. There are tons available, and in fact a recent thread on this forum identified several along with comments from the folks that had tried them. The simple way is the 7805 voltage regulator but that will burn off a lot of waste power, and you have none to spare.

    A better overall strategy would be to use the panels in parallel to charge several AA rechargeable batteries, and a step-up circuit such as the popular minty-boost project.

    Can't wait to see your results.
     
  14. Bernard

    AAC Fanatic!

    Aug 7, 2008
    4,173
    397
    Back to square one: Measure open ckt V of each panel & short ckt current. About 75% of the OC V will be available for charging, - diode drop of 1/2 V. Next what type of 9V battery, and mAh rating? Some Ni-Cd & Ni-mh 9 v batteries are really about 7.44Vs, 6 X 1.24 cells. The more information, the better the result.
     
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