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12v DC to 24v DC — Parallax Forums

12v DC to 24v DC

PLJackPLJack Posts: 398
edited 2005-03-08 15:59 in General Discussion
Is there a way to convert 12vDC (car battery) voltage to 24vDC voltage.

Thanks
Jack

Comments

  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-07 18:04
    Sure.
    There are lots of DC-DC converters on the market. Try a Google search. How many amps of 24 volts do you need?
    Maybe we can help you narrow something down.

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    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • steve_bsteve_b Posts: 1,563
    edited 2005-03-07 18:05
    Maxim sells an IC that will do that.· Limited amount of current though!

    The chip is the MAXIM ICL7662

    I've included the datasheet!


    ****· Oops, my mistake...this will only convert up to 20V....but look on the 6th page....the doubler circuit!

    Vout = 2Vin - 2Vdiode

    So, you could put in 12Volts but you would lose across the two diodes (2Vdiode).· Use germanium diodes maybe and you'd lessen the loss to 0.3V each!· Circuit might oscillate at the top of it's range!

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    ·

    Steve
    http://ca.geocities.com/steve.brady@rogers.com/index.html
    "Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

    Post Edited (steve_b) : 3/7/2005 6:10:49 PM GMT
    pdf
    pdf
    ICL7662-Si7661.pdf
    330K
  • paysonbadboypaysonbadboy Posts: 81
    edited 2005-03-08 05:05
    Sounds like a "charge-pump" IC Steve smile.gif

    Yeah, it would only supply enough power to use for logic IC's requiring low amounts of current.


    I have only had experience with one of those charge pumps and that was in a home made smart card reader/writer. i of course was GIVEN the schematic at the time and has been a while since I messed with any of that.


    Anything more maybe a simple switch mode through a hand wound toroid transformer. 24Volts would be easy.

    And if it didn't need any critical Pulse Width modulation you could simply use a 555 and one mosfet then regulate it somehow.

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    http://www.paysonarizona.net/
  • PLJackPLJack Posts: 398
    edited 2005-03-08 15:32
    I read the specs last night.

    I need 24v DC at just under 3 amps from a 12 car battery..
    I was hoping to make a power supply for it but I just might have to buy
    a a complete power supply for it.

    What do you think.?

    Jack

    UPDATE:
    So I looked around at some DC/DC converting units.
    The schematics are not one or two chip solutions.
    Two things.
    1:
    Seems the time and effort to build a "reliable" unit
    would surpass the time/cost of just buying a ready made unit.

    2:
    The unit that needs to be powered cost $8,000.00
    I would hate to damage the unit just to save a few bucks
    on the power converter.

    Unless someone has a simple (safe) idea for building a converter
    I will just go buy one.

    Thanks for your effort up to now.

    Jack

    Post Edited (PLJack) : 3/8/2005 3:53:08 PM GMT
  • The Dead BugThe Dead Bug Posts: 73
    edited 2005-03-08 15:35
    How about a second car battery (or smaller motorcycle battery) in series with the first? Cheap and easy?
    Bruce

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Name: Bruce Clemens

    Work:· Clemensb@otc.edu
    Good Stuff on my Blog: http://theDeadBug.journalspace.com
  • Tracy AllenTracy Allen Posts: 6,667
    edited 2005-03-08 15:58
    I just had to do that in order to run 24 equipment at field site. Our local electronics supplier had some "universal" DC-DC converters for $34 each, made in China. You can also find such adapters a t stores like CompUSA. There is a car battery plug on one end and a multi-plug adapter on the output side, and a selector switch for 15 to 24 volts out at 3 amps. This project needed the 24 volts to be controlled by the BASIC Stamp, so I added a transistor switch to ground on the input side. The quiessent current with no load was 90 milliamps, and the input from the 12 volts was 7 amps at full load. There was a huge transient pulse of 12.5 amps when the battery first connected, even with no load at the output, so I had to use a beefy transistor to do the switching.

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    Tracy Allen
    www.emesystems.com
  • PLJackPLJack Posts: 398
    edited 2005-03-08 15:59
    The Dead Bug said...
    How about a second car battery (or smaller motorcycle battery) in series with the first? Cheap and easy?
    Bruce

    I love simple solutions!
    My only concern is that automobile circuits are known to be violent.
    They batteries would need to be connected to alternators to charge them.
    Also I would need to buy four batteries. Two for the vehicle and two for
    bench testing.

    I like the idea though, thanks

    Jack
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