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TRSIX

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  1. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted

    Another update.

    I am measuring the current drawn by the batteries.

    Am I correct in assuming that the Solar Controller is dictating how much current is going into the batteries by how much below full they are?

    I am watching the current draw and on a sunny day, with no load on the batteries, the current dropped from 123mA and is now hovering around 45mA.

    (I am measuring the current by connecting the meter in the following configuration)
    Solar --- + side of meter - side of meter + side of solar controller --- battery

    Can I assume that the batteries are now full and the controller is just supplying a float charge? (as in : As the batteries fill up, they will draw less current)

    I have measured the batteries and they are all reading full.

    Just for clarification.

    Thanks
    Zach

  3. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted

    I have an update for my project.  

    I have worked out *most* of the issues but I have a question regarding current draw.

    I have a SolarTeck panel, MicroStar SunSaver 6 Solar Controller, and 4 x 12V 18ah batteries.

    I currently have 3 x 3.2v 20ma White LED's (approx 10,000 mcd) with a 220 OHM resister

    I am measuring the current thru my Ostra Digital Meter.

    I started the system up with a 500W light shining on the panel and I wanted to see the current drawn by the LED's for one complete circuit.

    It started out at 14.21mA and after about 20 minutes its now reading 14.54mA.

    My guess is that as the components warm up to working temperature, the resistances will level out and the current  will also level out.

    Does this sound correct to all of you?

    Solar Panel - > http://flic.kr/p/8KmYnv
    SunSaver 6 - > http://flic.kr/p/8KmYri
    LED Array - > http://flic.kr/p/8KmYu6
    Batteries - > http://flic.kr/p/8KmYyk
    Current Reading - > http://flic.kr/p/8Kq2Uu

  5. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted


    The battery won't fully charge at that voltage, to float charge a lead acid battery the voltage needs to be kept around 13.8V.


    I was reading the wrong information about the SunSaver 6. It has regulated voltage to the batteries:
    Regulation Voltage:
    Sealed Battery 14.1 V
    Flooded Battery 14.4 V

    I think I finally get what you are talking about.  It was hard for me to wrap my head around it before because I didn't understand fundamentally how LED's worked.

    I now understand that I must limit the current, lest a runaway situation happen where one LED heats up and starts to draw more current, which then causes it to fail, then the other LED's in the circuit fail too because of the current they take up.

    Tell me if this is correct:

    The maximum voltage the series of LED's will see is 14.1V (Under conditions where the Solar Panel is charging fully)
    Each LED uses 3.2V and ~20MA of current

    If I have 4 LED's in series, thats 12.8V at ~20MA

    If I then subtract 12.8 from 14.1, that leaves me with 1.3V left over.

    Putting that into OHM's Law Triangle I have 1.3V / 20MA = 65Ώ resistor.

    Is this correct?

  6. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted


    Odyssey make a wide range of batteries so I'm afraid that doesn't mean much.

    You are absolutely correct.  I was attempting to give a reference of size but I know that doesn't mean much when it comes to batteries.

    They are 12v 12AH Sealed Lead-Acid batteries.  I have 4 of them connected in parallel.



    The LEDs should not be connected across a constant voltage source without a current limiting resistor. The LEDs require a constant current source which can be approximated by connecting a resistor in series, Google for LED tutorial and you'll find plenty of advice on calculating the correct value.

    Yes.  I googled LED Tutorials and found many resources.  I believe what I have as a working model right now is correct... The "Sun Saver 6" solar controller has a LOAD connection which limits the voltage to 12.9 V.  Therefore there will never be more than that given to the load.


    You should connect the LEDs in banks of two or three LEDs in series, each with its own series resistor to the 12V battery.

    Right now I have 3 in series and a diode, which drops the voltage by another .6v.  That makes the voltage right now across each LED 3.95v.  This might be over driving the LED's by a bit so I will have to make sure its correct before I put them in place.

    What size are the LEDs? Are they in a standard 5mm package? If so the recommended current will probably be about 20mA.
     
    They are 5mm white LED's

    I will do more reading to determine exactly what is required to get this system to work as intended.

    Thanks for your assistance and I am sorry my answers are vague, I realize that doesn't make it easy to work with.

  8. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted

    The batteries are 12v but I'm not sure of the capacity.  They are gel-cell and are about 1/2 the size of a car battery, like the size of an Odessey battery.

    I am also not sure of the current rating of the LED's.  They appear to be just normal white LED's.  I burned one out (kind of on purpose) attempting to find out what voltage they want to run at and it appears to be 3V-4V.

    When I had 5V running thru one of them, it got hot and started to dim quickly so I guessed that was too much power.

    I am using the 12V-5V usb car adapter because I thought that would be the easiest way of getting the voltage of the batteries down to something useful.

    If the voltage of the LED's are supposed to be 3v-4v, how would I determine how many of them I would need to run in series to get the voltage down to what they require?

    I am sorry if I am asking simple questions here but I am just getting into hobby electronics.

    Thanks again for your assistance.

    Zach

  9. Solar and Batteries and LED's questions

    in Electronic Projects Design/Ideas

    Posted

    Hello, First time poster and new member to this site, please be kind and direct me to further information or correct posting locations if I am incorrect in anything I am posting here.  :) thanks for your assistance.

    Ok, Where do I start...

    I guess my project outline is I am interested in Solar power.  I recently bought a SolarTek panel.

    It's specs are:
    Model : ST-20W
    Rated Max Power (PMax) : 20Wp
    Max Power Voltage (vmp) : 17.5v
    Max Power Current (Imp) : 1.14A

    I also have some batteries:
    4 x RBC6 batteries (out of some APC UPS"s)

    I also have a SunSaver 6 (by MorningStar)

    I would outline this project as :
    Provide LED lighting to the stairs in my house (side lighting to illuminate the stair) via batteries charged by the sun.

    I have some LED's which I want to use to provide the light and a want to learn.

    I have been testing the current setup and have a "working prototype" which seems to be working but is currently only illuminating one LED and I want to have 56 (or more, to provide more light).

    I am using a 12v to 5v Car USB adapter to provide myself with 5v. ( i have placed a Diode in series with the working LED to drop the voltage )

    What would you suggest I do to make a circuit which would be capable of handling 56 LED's (3.8V each) which would be safe to run continuously.

    Please forgive my question if its very vague, I will respond to provide further information.

    Thanks for your assistance again.

    Zach

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