Question about Ryobi Multi-Volt Battery Charger

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Hello all you electronic nerds. I have a simple question so please do not try to give me a college education in your answer. I have an 16.8 drill battery without a charger. i need to find out if it will hold a charge. I do have an adaptor that is 18 volt ac output. My question is can you charge a DC battery with AC voltage. I don't meanm leave it on the battery and walk away. I mean touch it and pull away and touch it and pull away until you have the right amount of volts in the battery? I use wall warts or adaptors all the time to recharge aa batteries by clipping the end and with a meter finding out which is positive and negitive. I use a 4 volt dc output to put a quick charge on the aa battery's and it works great. But will the same theory work from a AC to DC? tHE rAZ

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  • Raz Mataz May 06, 2010

    What is a diode and where do i put it to change this. I read also you can take a round magnet and slip it over the wire or somethoing to make the electric flow in one direction. What about running a magnet strip from a refrigerator door seal?

  • Raz Mataz May 06, 2010

    Don't get me wrong, I just figured the long version would be way over my head which it is. I have this one 16.8 volt rechargable drill battery that I want to sell on ebay. I have wired in my travel trailer, to the 12 volt system, two wires that charge many things for me on the dc side. They charged theis battery to a point of almost 15 volts by my meter reading. It must be because the battery has about 8 or 10 small battery's inside connected to each other, because my meter shows the voltage coming out of the 12 volt lights in my trailer at 12.5 volts.
    I was wondering then if I took another wall wart power supply and disconnected the transformer inside but left the rest hooked up and then put my 18 volt wires to the two wall prongs and let it run through the other power supply if that would do it. There must be some sort of diode setup inside dc power supply units because they plug in to the ac outlet first and then change everything to dc. Do you think this is feasable? Thanks for your patience by the way. One way or other you will get that max thumbs up for your time. Raz/Don

  • Raz Mataz May 06, 2010

    So I found a broken wire and the thing is all hooked up and putting out the 18 volt dc like I'd hoped it would. The battery is at nearly 17 volt dc now and I will see if it holds the charge over night. Thanks for all your help. Raz/Don



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No. Not unless you also use the right size diode to make the AC go in one direction only.
AND---- Don't try anything like this with a Lithium battery! We're talking NiCad, right?

Posted on May 06, 2010

Testimonial: "Very helpfull and smart too..."

  • Al Kupchella
    Al Kupchella May 06, 2010

    I sense some frustration with not knowing some basics about electricity. Yet, you definitely have curiosity in this area. I think you might find it very satisfying to learn more, rather than dancing in the dark like this. I don't know your age, but you can learn a great deal in a high-school intro to Physics class. Or, adult education at a Vo-tech or a community college. ..... You said you wanted a simple answer, so I didn't try to tell you how to design and build the circuit that would enable you to use your 18VAC power supply. The major component is a diode (or 2), but you might need to add resistors too. A diode is an electronic component that allows current to travel in one direction, but not the other. Selecting the right one might be a challenge. (Try Wikipedia for an excellent lesson on diodes.) You might get lucky and find one at Radio Shack that will work. But many Radio Shacks don't sell parts like this any more. Regarding what you read on using magnets -- this was either a misunderstanding or complete nonsense.

  • Al Kupchella
    Al Kupchella May 06, 2010

    I've heard them called vampires, but wall-wart is a new one on me -- I like it. Anyway, using another wall-wart just might work. I think you have the right idea, but let me restate it (you threw me with the bit about putting your 18VAC as the input to the wall prongs). Sacrifice a wall wart that has the highest voltage and current rating you have (current will be stated in amps or milliamps (mA). 1000 milliamps = 1 amp. The wall wart contains a transformer, and the rest of the stuff is the rectifier. Cut the leads between them - that's important - to separate the transformer from the recitifier. Use your 18VAC power supply as input to the rectifier. It doesn't matter which wire is which with the AC. This should get you pretty close to 18VDC output. But just be forewarned, if the 18VAC power supply is big enough, and/or the battery is bad, you might toast the rectifier. Good luck.



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nice question man...So let us give a nice answer

Goto the place where it is installed->run it ....its so simple?


If u meant, learning it...



Was my tip helpful?


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