Question about amperage 12vdc

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  #1  
Old 01-02-13, 07:28 AM
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Question about amperage 12vdc

Ok, I'm building an inductive charging cell phone dock for my truck, and mounting it to my dash. I have the inductive charging dock built, but I need a way to wire it in. The charger came with an AC/DC converter that I could run to a DC/AC converter, but I think it would be silly to convert the power in both directions. The required input for the charger is 12v 750mA, does this mean that I can just wire it in directly to my 12v power supply? I know that it's not going to be a constant 12v, it ranges from 9 to 14 volts regularly, so should I use a DC/DC converter? I can not seem to find one that I would feel comfortable wiring in as they are meant for PCB boards. I am decent with a solder gun and might be able to use one of these, but do not know if that's the best way to go or not. If anyone knows of a product that I can wire inline that would be great, and once done, I will be happy to share pictures of the final product. Any help would be greatly appreciated. Thanks.
 
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Old 01-02-13, 07:34 AM
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Look at a voltage regulator IC. They're pretty inexpensive and seem to work well for me.
 
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Old 01-02-13, 09:18 AM
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The 3pin regulator IC's work great but they can't raise the voltage and you need to supply them with several volts over the regulated voltage.

A DC-DC convertor for a 1 amp load can be pretty pricey.

Does your item need the voltage to be regulated ?
It would seem that you could wire it to an accessory port on your ignition switch.
Use a 2 or 3 amp fues inline.
 
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Old 01-02-13, 11:58 AM
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I'm not sure how sensitive the inductive charger is, I would assume that it could take a little over or less, as most things can. But I would rather err on the side of caution and make sure that it's not going to burn up on me and I'd have to start all over again. I think I might have to go with a DC/DC converter, about $50-$60 bucks as far as I can tell, but then I wouldn't have to worry about the whole thing turning into an real expensive phone dock.
 
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Old 01-02-13, 08:02 PM
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*Update* I went to Radio Shack and found a 12v 1A DC power supply, swapped out the fuse for a 3/4amp fuse and wired it up. So far it's working fine and now all I need is a mount system and run the wires behind the dash for a nice clean look. Hopefully will be done by the weekend
 
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Old 01-02-13, 10:07 PM
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I went to Radio Shack and found a 12v 1A DC power supply
and what.............a real long extension cable ?



Is this one of those cigarette lighter plug things ?
It will drop the voltage if hi but wont raise it if low.
 
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Old 01-03-13, 12:56 PM
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Yeah, it's a lighter plug accessory, ended up being much cheaper than a DC/DC converter and much easier than a regulator. I'm not too worried about the voltage being to low as the voltage from the lighter plug in my truck is around 14v at idle (at least that's what my meter says). When the engine is off, it drops down to around 9, but I shouldn't be trying to charge my phone with my truck off anyway. I have a lighter plug in the console that I don't ever use so I'm gonna run the wires into it and plug it in. I might actually hard wire it into the truck with a converter if I get in the mood to do it the correct way later, but my guess is if I don't see it then I won't care.
 
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Old 01-03-13, 04:06 PM
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You have a bad battery if the voltage drops to 9 volts when the engine is off. Normal battery voltage when not being charged is 12.0 to 12.5 volts.
 
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