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12V DC to 12V AC

  1. May 10, 2017 #1
    Hey all,

    A 'rank' newbie here, so please bear with me. ;-)

    I have a 'solar charged' 12V battery (with charger) for an electric fence charger. I'd like to use this solar charger and battery to power a 12V AC (I think) low voltage landscape bug zapper. It 'must' be 12V AC, I think?

    Is there a fairly easy/cheap way to do this, or am I having pipe dreams?

    Thanks!!!

    Phil
     
  2. jcsd
  3. May 10, 2017 #2
    It might be very simple, but you need to know more about each of the components.

    How many amp-hours is the battery?

    What is the actual power requirement for the bug zapper? Saying "12V AC (I think)", isn't going to get you there. How much voltage, how much current? AC or DC? Maybe a model number of the device if you can't determine this info.
     
  4. May 11, 2017 #3
    The Battery is 14 AH. The Zapper is Malibu Landscape Lighting Model 8401-4501-01. It says LED 12V, 1.3W.

    Thanks!
     
  5. May 11, 2017 #4
    When I looked up that model number, it does not include a power supply, it says to use with a low voltage landscape system. It wasn't 100% clear to me if all those systems are AC or DC, or what the voltage tolerance is. What were you using to power the bug Zapper? What are the specs or readings on it (do you have a meter?)?

    Assuming it is DC (likely), you can probably connect it directly to the battery. I say probably, because a battery while charging might go up to ~ 13.8 V, so the question is if the Bug Zapper can accept that slightly higher voltage ( probably).

    If it can be connected directly, a fully charged 14 AH battery , the zapper draws about .11A, so about 127 hours of operation - looks good.
     
  6. May 11, 2017 #5
    The Zapper is new, and has never had power (of any sort) to it. Do you mean resistance in ohms? I just tried, and get no measurement at all... like an open. Tried pushing the selector button (light vs UV light) and still nothing. I also looked up a Malibu 300W Power Pack and see this -
    • 300 Watt Outdoor Power Pack Transformer
    • Converts 120 Volt household electricity to a safe 12 volts(AC)
    Any way to convert the DC (from battery) to AC?

    Thanks!

    Phil
     
  7. May 11, 2017 #6
    It's not surprising you get no R readings, the unit probably is not resistive.

    I also see 12 V DC landscape power supplies for sale. I'd give 99:1 odds your bug zapper works on AC or DC, they probably put a full wave rectifier in the front end to accommodate this (and also guarantee you would get high R with an ohm-meter). You could write the manufacturer and ask if AC or DC is OK.

    Maybe someone more familiar with these landscape systems can comment. Or maybe current limit the supply and just try it? a 10 Ohm R in series with the battery would drop about 1.1 V @ the 0.11 A draw, and provide some protection.
     
  8. May 11, 2017 #7

    jim hardy

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    It's a fairly safe bet the bug zapper rectifies 12Vac into 12-15 volts DC and steps that up to the hundreds of volts necessary to "zap" bugs.
    But i'd give odds of five to one rather than NTL's 99 to one.

    So it's only a fairly safe bet.

    What is the cost of that Zapper ? If it's only a few bucks that you're willing to lose,,,
    Connect it to 12 volt battery through a large 12 volt lamp like a car headlight bulb.
    If the lamp lights brightly you shouldn't try to run it on DC.
    If the lamp glows very dim or not at all, then you can try it on DC BUT with knowledge you still might wreck it.

    So it comes down to whether you're willing to risk the cost of that Zapper for a chance at convenient DC power.
    Myself i'd risk five bucks but not twenty-five.

    If it's easy to open, post a picture of its innards.

    old jim
     
  9. May 11, 2017 #8
    $14, so it won't change my lifestyle if I make some internal components into external components. ;-)

    Here are 2 pics - couldn't get the board any further out with all the wires connected.

    Thanks!

    Phil Back_Of_Board (Medium).JPG Most_Components (Medium).JPG
     
  10. May 11, 2017 #9
    OK, I'm assuming the two thicker black wires on the lower left of pic #1 are the input power connections?

    Those are connected to a 4-lead device, so that is most likely the full-wave (bridge) rectifier I mentioned earlier. That should make it universal for AC/DC ( but there can be exceptions, since the peak of a rectified AC signal will be 1.4x the peak of a DC, and/or, they could still be looking for a 60 or 120 hertz signal for other purposes). But I really, really doubt those exceptions apply.

    Are the markings on that part a (+) and a (-) and a (~)? That's how they usually mark packaged bridge rectifiers. I think you are good to go - Jim Hardy's idea of connecting through a 12 V auto bulb is a good one in any case, just to see if there are any load issues.
     
  11. May 11, 2017 #10
    Yes, incoming up through the stake. The only 4 leads I see are the blue, yellow, red, and white? They go Up into the zapper body in pic #2, and since this a "dual function" unit, I don't think it's a rectifier? Don't see any markings as you suggest. The 2 "modes" are "LED only", and "zapper mode with UV light", so just 2 separate circuits? The extra red wire is going in and out of the push button to toggle between modes. It's in that 'block with the silver screw' at the bottom of pic #1.

    How to connect thru the bulb? In series?

    Thanks!

    Phil

    PS - The black and yellow 'box' in pic #2 has 5 places it's connected to the board. "19301" is on the side of it. Also, the large Orange part has 'CBB81' and '2000V223J' printed on it. Not sure if this info helps?
     
    Last edited: May 11, 2017
  12. May 11, 2017 #11
    I see 2 black wires in the lower left of pic #1, and again on left of #2. Those look like the 12 V input to me - is the picture making this look different than real life? What do those wires go to? I assume some sort of 12 V connector (or just bare wires)?

    The 19301 label is the transformer/inductor probably to step up the voltage for the bug zapper, the orange part is probably a 2000 Volt rated capacitor, also for the bug zap circuit, but those markings aren't always standardized.

    Yes, just put the auto bulb in series from the battery to the input of the bug zapper. Get it all closed up carefully, you only want bugs to get zapped!
     
  13. May 11, 2017 #12
    The 2 black wires are soldered to the board - the 2 brownish looking solders on the lower left corner of the board in pic #1. They show again in pic 2 on the left side corner of the board - what I did was just turn my wrist from palm up in pic 1 - to palm down in pic 2 to show the underside of the board.

    I'll try the bulb and see what happens. Bet it might not be as bad as touching that 12k volt electric fence though? :-D

    Thanks!

    Phil
     
  14. May 11, 2017 #13

    jim hardy

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    I agree with NTL it looks like power comes straight into abridge rectifier.

    BugZapper1.jpg
    That thing should be impervious to polarity.

    Unless it uses 60 hz for some internal timing or charge pump it will work on DC.

    If i had one i'd try it .


    Sort through the trays of old AC adapters in thrift shops. You'll run across one sooner or later that makes 12 VAC. Old video games used them.

    Good Luck !

    old jim
     
  15. May 11, 2017 #14
    OK, Guys That's an Aha! moment for sure. ;-)

    Tomorrow I'll hook 'er up and see what gives. Had no idea that that D4? where the cables come in, was a rectifier on the board. Yikes... time for a self inflicted Dope Slap. ;-)

    I can probably wire a house with 110/220 AC and also run straight DC around a boat or vehicle, but when we get to all these ohms/resistors/AC/DC, etc. I'm a baby!

    Will post back when tested. Fingers crossed, but based on you guys' knowledge, I'm Hopeful! Then again, $14 for the zapper won't be a drastic loss. I'm also a tiny bit like Myth Busters, and kind'a like to watch things explode. ;-) Hoping it all works for this though! :-D

    I expect that it will, and Thanks!!!

    Phil
     
  16. May 11, 2017 #15

    jim hardy

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    I can fix a tube radio. Ever feel like a dinosaur veterinarian pining for Jurassic Park ?

    What we do here is share what we know, and learn from everyone who shares.. It's good for one's humility.

    old jim
     
  17. May 12, 2017 #16

    OCR

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    I think you actually do have an open, the bug provides the "switch" that closes the circuit... and pays for it dearly.
    An electrical discharge insect control system...

    Lol... ...
    Besides touching one... I've also heard of another act that should be avoided on an electric fence... lmao-gif.gif
    Leaky spark plug wires can cause unhappiness, too... lol
     
  18. May 12, 2017 #17
    This AM I put the zapper all back together and touched the 2 leads to the 12 V battery wires. No smoke, flames, or loud noises... and the light even came on! :-)

    Just ordered an 12v photo cell dusk-to-dawn switch ($3.79), so I should be in business shortly.

    Thank you for your time and patience!!!

    Phil
     
  19. May 12, 2017 #18

    jim hardy

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    Great News , Thanks !

    Let us know that it still "zaps" ?

    old jim
     
  20. May 12, 2017 #19
    Yes! This experiment is not complete until some mosquitoes are harmed! :smile:
     
  21. May 12, 2017 #20
    Will do guys!

    I do believe that I've encountered another challenge though. The zapper has a push button "toggle" switch to change between "LED light only" and "zapper with UV light". It apparently defaults to "light only" when first powered on, and then the switch has to be pushed to change it over to zapper mode. I'll bet that a quick solder of a jumper wire somewhere might be a cure? I don't care about having the "LED light only" mode at all, just having the zapper come on.

    Thanks!

    Phil
     
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