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Mimicking a 14.4VDC Speaker Charger

  1. Aug 16, 2016 #1
    Good day Everyone,

    I am going camping and I am rigging up a couple small solar power setups, I have a 12V 26AH Battery with a solar panel and appropriate solar charge controller. I will use this to charge a few 5V devices(Mostly cell phones for taking pictures and videos). Anyway that setup is pretty straight forward, I am using cell phone chargers made for use in car's cigarette lighter port

    But I also want to take this portable bluetooth speaker I bought and be able to charge it. The charger that comes with the speaker says it has an output of 14.5VDC @ 2.5 Amps.I want to know if you guys think I can make a DC to DC charger without damaging the speaker?

    My theory is to start off with a 24VDC Battery bank. Then buy one of these[https://www.amazon.com/DROK-Regulat...r=8-2&keywords=variable+step+down+transformer variable DC to DC step down transformers and dial it in to 14.5DVC. Do you guys think this would work? Or is there something special that the charger does other than provide 14.5VDC? Of course I would manually monitor the charge level of the speaker and unplug it once it is fully charged, but other than that I think I should be fine right?

    Any input is appreciated, thank you guys.

    -Eddie
     
    Last edited by a moderator: May 8, 2017
  2. jcsd
  3. Aug 19, 2016 #2

    berkeman

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    Staff: Mentor

    What is the input for the speaker charger? AC Mains? What voltage and what current are specified for the charger's input?

    It might be simplest to just get an AC Mains Inverter that runs off of your 12V supply. You'd have to calculate how long your 26AHr battery will last with the Inverter and Charger connected...
     
    Last edited by a moderator: May 8, 2017
  4. Aug 19, 2016 #3

    sophiecentaur

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    Science Advisor
    Gold Member

    A battery charger is specific for a particular battery technology. You should never try to charge any old battery from any old power source; batteries can be damaged and blow up. It is likely that your 'Battery Charger" is actually just a Power Supply which feeds your Speaker and the speaker has its own internal charging / controller circuit. This is the system that cell phones and tablets use. Your speaker probably wants a nominal 12V power input and the 14V value represents what you get from a Car '12V' supply socket when the engine is running and the car battery is fully charged.
    That's what your PV panel / 12V accumulator system will give you. Do you have a proper charge controller for it? Messing about, shifting voltage levels is not very efficient when you have limited energy supply.
    Best to see what your speaker actually wants as an input. An internet search will probably tell you (or look at any figures on the plastic case right next to the power input socket).
     
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