24v dc to 72v dc

Discussion in 'The Projects Forum' started by siriggy, May 14, 2007.

  1. siriggy

    Thread Starter New Member

    May 14, 2007
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    Hi could anyone help, i have a UPS which has 6 x 12 v batterys in series. and i would like to charge it with 24v dc. can this be done.
    steve
     
  2. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Sure. If they physically fit, you could do three 24V batteries at the same AH rating.
     
  3. siriggy

    Thread Starter New Member

    May 14, 2007
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    Hi joe what do u mean 3 24v batterys ain't all car batterys 12v
     
  4. Papabravo

    Expert

    Feb 24, 2006
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    Probably meant three groups of two batteries. Some antiques have 6V systems and some modern vehicles have 42 V systems. I've seen the 6V batteries, but I've never seen a 42V one.
     
  5. siriggy

    Thread Starter New Member

    May 14, 2007
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    my inverter needs 72vdc, how can i charge the batterys with 24vdc from the bus alternator, if all the batterys are in series.

    steve
     
  6. siriggy

    Thread Starter New Member

    May 14, 2007
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    would this circuit work
     
  7. Papabravo

    Expert

    Feb 24, 2006
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    The short answer is no. The only way I can see doing what you want is to change the configuration during charging. The charging voltage needs to be larger than the battery voltage in all cases that I am familiar with. Where exactly did you get this fancifal notion?
     
  8. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    I misread the question.

    Since you have a UPS, it already has a charging circuit to charge the battery pack [6 x 12]. Why would you want to charge them with a 24 volt supply?

    What is the problem with your UPS?
     
  9. siriggy

    Thread Starter New Member

    May 14, 2007
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    i am converting a bus into a mobile home and want to use the ups as my 240vac supply but i need to charge it on the road, i will plug in in 240 at caravan park.
    steve
     
  10. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Get a small generator. Then you can charge the UPS as needed from wherever. Most Class "A" motor homes have small generators.
     
  11. Johann

    Senior Member

    Nov 27, 2006
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    Perhaps someone can come up with a DC to DC converter that will do the job? I did a google search on the topic, found many, but not in that voltage conversion range.

    It could be a challenge to try and convert a vehicle alternator to a higher voltage (with the correct regulation) and fit it as a second alternator to your motor home.
     
  12. JoeJester

    AAC Fanatic!

    Apr 26, 2005
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    Some owners of a Class A mobile home will run their generators while driving down the road to charge their UPS and run the roof top Air Conditioners instead of running the normal vehicle Air Conditioner.
     
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