Notices
Results 1 to 17 of 17
Like Tree1Likes
  • 1 Post By MacGyver1968

Thread: Garden Solar Lamp Help.

  1. #1 Garden Solar Lamp Help. 
    Forum Freshman WaterWalker's Avatar
    Join Date
    Jan 2013
    Location
    KZN, South Africa
    Posts
    79
    Hi all. So, here's the deal. My parents have a few of these solar lamps, and 3 of them have stopped working. So now I want to repair the broken ones, and maybe "upgrade" the existing ones. Now, I have searched quite a few websites - Instructables, Electroniqs, Evilmadscientist to name just a few. Biggest problem is I don't have all the correct parts, only a handful of it. Here's my thoughts so far: I'm gonna replace the factory spec battery (AA 1.2V 300mAh) with a slightly different one (AAA 1.2V 700mAh). Now, some of the diagrams I've seen employ an inductor. Although that would make the circuit more efficient, I don't have any prebuilt inductors. And no way to build one to spec. Although, help with this will be appreciated. Any websites? I have a select few components, basic starter electronic enthusiast.


    "No army is stronger than an idea whose time has come." - Victor Hugo

    Dywyddyr - "You're rather good at denying reality, aren't you?"
    Plautus - "False."
    Dywyddyr - "And you've done it again. Well done. Would you like a biscuit?"
    Reply With Quote  
     

  2.  
     

  3. #2  
    Forum Professor
    Join Date
    Aug 2013
    Location
    San Diego
    Posts
    1,970
    Quote Originally Posted by WaterWalker View Post
    Hi all. So, here's the deal. My parents have a few of these solar lamps, and 3 of them have stopped working. So now I want to repair the broken ones, and maybe "upgrade" the existing ones. Now, I have searched quite a few websites - Instructables, Electroniqs, Evilmadscientist to name just a few. Biggest problem is I don't have all the correct parts, only a handful of it. Here's my thoughts so far: I'm gonna replace the factory spec battery (AA 1.2V 300mAh) with a slightly different one (AAA 1.2V 700mAh). Now, some of the diagrams I've seen employ an inductor. Although that would make the circuit more efficient, I don't have any prebuilt inductors. And no way to build one to spec. Although, help with this will be appreciated. Any websites? I have a select few components, basic starter electronic enthusiast.
    Need some more info. Is it an LED lamp? If so then that inductor is part of a boost converter to generate 3.6 volts from 1.2 volts. This will be essential to getting the circuit to work. Search for "boost converter" on the Texas Instrument website and you will see a lot of options.


    Reply With Quote  
     

  4. #3  
    Forum Freshman WaterWalker's Avatar
    Join Date
    Jan 2013
    Location
    KZN, South Africa
    Posts
    79
    Oh, my bad. Yes. It is an LED circuit. But, I just wanna make sure, I definitely need the inductor? I guess I was hoping to do without it.
    "No army is stronger than an idea whose time has come." - Victor Hugo

    Dywyddyr - "You're rather good at denying reality, aren't you?"
    Plautus - "False."
    Dywyddyr - "And you've done it again. Well done. Would you like a biscuit?"
    Reply With Quote  
     

  5. #4  
    Forum Professor
    Join Date
    Aug 2013
    Location
    San Diego
    Posts
    1,970
    Quote Originally Posted by WaterWalker View Post
    Oh, my bad. Yes. It is an LED circuit. But, I just wanna make sure, I definitely need the inductor? I guess I was hoping to do without it.
    You can't, not with only one 1.2 volt cell. (BTW you need a lot more than just an inductor for a boost converter.)
    Reply With Quote  
     

  6. #5  
    Forum Freshman WaterWalker's Avatar
    Join Date
    Jan 2013
    Location
    KZN, South Africa
    Posts
    79
    Saw that now. Just did a wiki search of the boost converter. (And basically for that reason I kinda wanna leave it out). But, I'm only just starting to learn about electronics, so forgive my ignorance. I recently built a LED circuit using 2 x 2N2222 transistors, 4 resistors, 2 micro-switches and 2 LEDs commonly connected at the negative terminals. All that was connected to a single 1.5V cell. Can't I maybe use that transistor for some low power gain?
    "No army is stronger than an idea whose time has come." - Victor Hugo

    Dywyddyr - "You're rather good at denying reality, aren't you?"
    Plautus - "False."
    Dywyddyr - "And you've done it again. Well done. Would you like a biscuit?"
    Reply With Quote  
     

  7. #6  
    Forum Professor
    Join Date
    Aug 2013
    Location
    San Diego
    Posts
    1,970
    Quote Originally Posted by WaterWalker View Post
    Saw that now. Just did a wiki search of the boost converter. (And basically for that reason I kinda wanna leave it out). But, I'm only just starting to learn about electronics, so forgive my ignorance. I recently built a LED circuit using 2 x 2N2222 transistors, 4 resistors, 2 micro-switches and 2 LEDs commonly connected at the negative terminals. All that was connected to a single 1.5V cell. Can't I maybe use that transistor for some low power gain?
    You might get some output out of a red LED at those voltages (min voltage 1.8V or so) but definitely not out of a white LED of the type used in solar lights (min voltage around 3.3 volts.) There's an IC out there (the LM3909? something like that) that does a capacitive boost; this lets you run a red/orange/yellow/green LED handily at 1.5 volts but not a white or blue. If you were happy with, say, an orange LED, you could use one of those IC's (along with a few caps) to operate from a 1.2 volt battery.
    Reply With Quote  
     

  8. #7  
    Theatre Whore babe's Avatar
    Join Date
    Jun 2013
    Location
    Resident of Big Island of Hawai'i since 2003, and in Bayside, Ca. since 1981, Humboldt since 1977
    Posts
    12,440
    We have had the worse worst time with our solar lamps....but then we need to wire them to hook up to our solar house.....I think we have given up on them otherwise.....we only really want them for safety for older folk
    Reply With Quote  
     

  9. #8  
    Forum Senior
    Join Date
    Jun 2013
    Posts
    309
    A joule thief might work, though I've never built one. They are a crude boost converter, and about double the voltage (by increasing the amp draw).
    Making your own induction coil shouldn't be that hard, though. I suppose you could use a 3.5v supercap charged by the battery to boost the voltage, but I'm not sure how you would cut off the output if the voltage dropped too low.
    Reply With Quote  
     

  10. #9  
    Forum Senior
    Join Date
    Jun 2013
    Posts
    309
    *accidental duplicate deleted*
    Reply With Quote  
     

  11. #10  
    Theatre Whore babe's Avatar
    Join Date
    Jun 2013
    Location
    Resident of Big Island of Hawai'i since 2003, and in Bayside, Ca. since 1981, Humboldt since 1977
    Posts
    12,440
    Quote Originally Posted by TheUnknowable View Post
    A joule thief might work, though I've never built one. They are a crude boost converter, and about double the voltage (by increasing the amp draw).
    Making your own induction coil shouldn't be that hard, though. I suppose you could use a 3.5v supercap charged by the battery to boost the voltage, but I'm not sure how you would cut off the output if the voltage dropped too low.
    My husband is a genius in numbers and business.....we started with ZILCH....but I really rarely ask him to change a light bulb
    Reply With Quote  
     

  12. #11  
    New Member
    Join Date
    May 2014
    Location
    India
    Posts
    1
    Solar street lights and garden lights are in more demand now a days. The reason behind the use of solar led lighting is that it has many benefits such as efficiency, long life, optimum light intensity and less heat emission. Is there any one know how to select the garden solar lights among the best? There are a variety of LED lights are available in the market, I am confused which one to buy.
    Reply With Quote  
     

  13. #12  
    Forum Isotope
    Join Date
    Feb 2012
    Location
    Western US
    Posts
    2,638
    Quote Originally Posted by WaterWalker View Post
    Saw that now. Just did a wiki search of the boost converter. (And basically for that reason I kinda wanna leave it out). But, I'm only just starting to learn about electronics, so forgive my ignorance. I recently built a LED circuit using 2 x 2N2222 transistors, 4 resistors, 2 micro-switches and 2 LEDs commonly connected at the negative terminals. All that was connected to a single 1.5V cell. Can't I maybe use that transistor for some low power gain?
    It's great that you are willing to learn. I have to say, though, that you'd be far better off buying something from off the shelf, building a proven design or simply fixing the broken one. Otherwise, here is a partial list of things you need to know before you can even start a design:

    1) The voltage and current needed to light up the LED(s).
    2) The voltage and current supplied by the solar cell (you'll find that the voltage is far below what an LED needs, and below even what the battery needs).
    3) Why 2) implies the need for a voltage boosting circuit.
    4) Why 3) most commonly implies the need for an inductor (although there are capacitor-only boost circuits).
    5) Why 4) implies the need to understand how an inductor works.
    6) Why 2)-5) imply the need for transistors acting as switches.
    7) Why 6) implies the need to know how transistors work.

    And that's only a partial list!

    That's why I suggest just troubleshooting the one that's broken. Doing so will give you a good education. Here are some things to look at:

    First, test the battery. Does it hold a charge (charge it up with another, known good battery or something similar)? What is the voltage across it? The battery, by the way, is the most unreliable component in these sorts of products. First, the manufacturer typically chooses the cheapest one available. Second, the simple circuits used rarely charge the battery in a way that maximizes battery life. I went through the exercise of fixing about 20 similar lights around our home last summer; all but two of the non-working ones had dead batteries. The other two had corroded battery terminals.

    Next, measure the voltage across the terminals of the solar cell. Is it about right? Does it supply a decent amount of current when light is shining on it?

    If the solar cell and battery are fine, check the LED.

    Inspect all connections for signs of corrosion, dodgy solder joints, broken wires, etc.

    There's very little in these things, so fixing them is straightforward. And the education you pick up during troubleshooting will put you in good stead when you decide to take the plunge and design your own someday.

    Good luck!
    Reply With Quote  
     

  14. #13  
    Theatre Whore babe's Avatar
    Join Date
    Jun 2013
    Location
    Resident of Big Island of Hawai'i since 2003, and in Bayside, Ca. since 1981, Humboldt since 1977
    Posts
    12,440
    Quote Originally Posted by tk421 View Post
    Quote Originally Posted by WaterWalker View Post
    Saw that now. Just did a wiki search of the boost converter. (And basically for that reason I kinda wanna leave it out). But, I'm only just starting to learn about electronics, so forgive my ignorance. I recently built a LED circuit using 2 x 2N2222 transistors, 4 resistors, 2 micro-switches and 2 LEDs commonly connected at the negative terminals. All that was connected to a single 1.5V cell. Can't I maybe use that transistor for some low power gain?
    It's great that you are willing to learn. I have to say, though, that you'd be far better off buying something from off the shelf, building a proven design or simply fixing the broken one. Otherwise, here is a partial list of things you need to know before you can even start a design:

    1) The voltage and current needed to light up the LED(s).
    2) The voltage and current supplied by the solar cell (you'll find that the voltage is far below what an LED needs, and below even what the battery needs).
    3) Why 2) implies the need for a voltage boosting circuit.
    4) Why 3) most commonly implies the need for an inductor (although there are capacitor-only boost circuits).
    5) Why 4) implies the need to understand how an inductor works.
    6) Why 2)-5) imply the need for transistors acting as switches.
    7) Why 6) implies the need to know how transistors work.

    And that's only a partial list!

    That's why I suggest just troubleshooting the one that's broken. Doing so will give you a good education. Here are some things to look at:

    First, test the battery. Does it hold a charge (charge it up with another, known good battery or something similar)? What is the voltage across it? The battery, by the way, is the most unreliable component in these sorts of products. First, the manufacturer typically chooses the cheapest one available. Second, the simple circuits used rarely charge the battery in a way that maximizes battery life. I went through the exercise of fixing about 20 similar lights around our home last summer; all but two of the non-working ones had dead batteries. The other two had corroded battery terminals.

    Next, measure the voltage across the terminals of the solar cell. Is it about right? Does it supply a decent amount of current when light is shining on it?

    If the solar cell and battery are fine, check the LED.

    Inspect all connections for signs of corrosion, dodgy solder joints, broken wires, etc.

    There's very little in these things, so fixing them is straightforward. And the education you pick up during troubleshooting will put you in good stead when you decide to take the plunge and design your own someday.

    Good luck!
    *laughing*

    Ya wanna come and do some solar lights? *L*
    Reply With Quote  
     

  15. #14  
    Forum Isotope
    Join Date
    Feb 2012
    Location
    Western US
    Posts
    2,638
    Quote Originally Posted by babe View Post
    *laughing*

    Ya wanna come and do some solar lights? *L*
    I'll be over this weekend, toolbox in hand.
    Reply With Quote  
     

  16. #15  
    Theatre Whore babe's Avatar
    Join Date
    Jun 2013
    Location
    Resident of Big Island of Hawai'i since 2003, and in Bayside, Ca. since 1981, Humboldt since 1977
    Posts
    12,440
    Quote Originally Posted by tk421 View Post
    Quote Originally Posted by babe View Post
    *laughing*

    Ya wanna come and do some solar lights? *L*
    I'll be over this weekend, toolbox in hand.

    ahahhahahah wait a month! *L*.....
    Reply With Quote  
     

  17. #16  
    Theatre Whore babe's Avatar
    Join Date
    Jun 2013
    Location
    Resident of Big Island of Hawai'i since 2003, and in Bayside, Ca. since 1981, Humboldt since 1977
    Posts
    12,440
    Kidding aside....we are thinking of doing that for safety reasons.......it gets dark in places with no street lamps!!
    Reply With Quote  
     

  18. #17  
    Cooking Something Good MacGyver1968's Avatar
    Join Date
    Aug 2006
    Location
    Dallas, Texas
    Posts
    2,051
    Hey, fly me to Hawaii and I'll fix anything you want!
    babe likes this.
    Fixin' shit that ain't broke.
    Reply With Quote  
     

Similar Threads

  1. Come and see my Garden. I have bees and flowers.
    By westwind in forum Art and Culture
    Replies: 0
    Last Post: April 11th, 2012, 12:31 AM
  2. 'solar' lamp
    By bobby2009 in forum Earth Sciences
    Replies: 6
    Last Post: March 25th, 2010, 12:21 AM
  3. dynamo lamp
    By scientist91 in forum Physics
    Replies: 6
    Last Post: August 15th, 2008, 07:54 PM
Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •