Solar panel power regulator

Discussion in 'General Electronics Chat' started by tigerfish0102, Oct 17, 2009.

  1. tigerfish0102

    Thread Starter New Member

    Oct 17, 2009
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    Hi Guys,
    I would design a power regulator to my solar panel. Can you me guys. What will be my first step?
     
  2. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    What are the requirements?
    Input voltage?
    Output voltage?
    Currents?

    Greetings,
    Bertus
     
  3. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    If you already have a panel, list short circuit current & open circuit voltage, then decide what battery system you wish to charge.
     
  4. tigerfish0102

    Thread Starter New Member

    Oct 17, 2009
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    Hi Bertus, i have 2 solar panel, i'am planning it to give power to refrigerator which is 10cu.ft. I will use the power regulator to charge the battery and then convert the battery power to AC to power up my refrigerator. My solar panel output voltage is 12V and output current 5amp. Do you think it is possible to do this?
     
  5. tigerfish0102

    Thread Starter New Member

    Oct 17, 2009
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    Please advice what battery system is better to use with this project. The SC current is 5amps and OC voltage is 12V. I have already the panel from a junk shop, i test it and its ok. I test it by brought it to sunligt and meassure the output and it the same with the nameplate. Do you think this is enough to confirm that the panel is good or not?
     
  6. bertus

    Administrator

    Apr 5, 2008
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  7. Thav

    Member

    Oct 13, 2009
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    That link doesn't much look like a regulator. It's a somewhat complicated circuit to try to understand from the schematic and text, but I don't see an inductor anywhere so I think it's just connecting nodes through FETs or doing some linear regulation. Of course I don't have a better link to share yet.

    I think the best course of action is a switching converter. The more you spend on the converter (which I don't think will be too much for a ~50W converter) the less energy you waste which means the money you spent on the panels can actually go further in reducing your energy bill. The real trick to solar converters is that you will likely want a controller capable of maximum power point tracking (you'll see this referred to as MPPT). Basically this means you can't draw 5A at 12V. You will only see 12V on the panel when the current is zero. Likewise you will only draw 5A when the output voltage is at zero. If I were to guess off hand, you'll probably be able to draw maximum power at 10V and 4A. For your controller to extract the most power possible from the panel, it needs to figure out where that maximum power point is, which changes with sunlight on the panel, age of the panel and other factors.
    Here is some reading on that phenomenon.
    http://en.wikipedia.org/wiki/Photoelectric_cell#Equivalent_circuit_of_a_solar_cell
    http://en.wikipedia.org/wiki/Maximum_power_point_tracking

    Here's a good looking reference design from ON Semi. It's roughly in your voltage range (if you connect your panels in series), but at maybe half your rated current.
    http://www.onsemi.com/pub_link/Collateral/DN06054.PDF
     
  8. MikeML

    AAC Fanatic!

    Oct 2, 2009
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    I have never seen a refrigerator that runs on 60W; more like 500W to 1000W is typical. Even my Peltier wine cooler takes more than 60W.
     
  9. BMorse

    Senior Member

    Sep 26, 2009
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    First off the panels would have to put out 13.8 to 14.5 volts to charge a 12 volt SLA (Sealed Lead Acid) battery. Normally for solar and wind generators, the output of the panels will be drawn down to the battery voltage anyways. And solar charge controllers are not efficient in the way they divert the power, usually when the batteries are fully charged, the charge controller will just short out the panel leads which usually wastes energy and heats up the transistors in the controller.

    What you need to power your fridge is a lot more than what your panels can put out,
    You can not drain your batteries down to less than 11 volts, or sulfation (lead sulfate builds up on the cells and shorts them out.) will occur and they wont hold as much of a charge, and eventually, wont even charge.

    Just as an example : If you have a PC that consumes 35 to 91 watts, and a TFT screen that consumes 27 watts, you will need a 1560Wh (130Ah) battery and a 260 watt solar panel just to run the PC for 23 Hours..... that's if you get at least 10 hours a day of sunlight.

    See the charge controller I made for my Wind Generator that also works for solar and hydro >>> http://www.morse-code.com/id184.htm

    My .02
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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  11. tigerfish0102

    Thread Starter New Member

    Oct 17, 2009
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    thanks guys..i will just use it for the street light..
     
  12. tigerfish0102

    Thread Starter New Member

    Oct 17, 2009
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    Hi bertus,
    I have only 5% knowledge regarding the electronic circuit. I'am electrician by profession in the vessel. I want to study the electronic circuit. I want to save the videos on the semiconductor and others the concern regarding the electronics in the allaboutcircuits.com. I have only limited access of internet co'z right now i'am onboard a vessel in singapore. I would like to save it so that even though i have no internet i can lissen to the videos as often as i could so that i could learn little by little. I hope you can help me.
    thanks,
    Vic








     
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