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Specifically, I have an Alarm Clock iPod dock with speakers that gets its power from ac wall adapter, but is only providing 12v. Is there an adapter to go 12V to 12V that will power this?

I want to put this in my camper, but run on 12V so I dont need to be plugged into shore power or have engine/generator/inverter running. I already have inverters and a generator, but this is for when dry camping and not running the engine. I have 200 watts of solar, so I am not too worried about running down my house batteries. I would rather use a standard cigarette adapter than hard wiring it to keep it portable.


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You just need to find the right barrel connector for your clock and wire it to your camper 12V battery. If this will be a permanent installation, wire it directly to a 12V tap. If needed temporarily, wire it to a cigarette lighter adapter.

Take your barrel connector to RadioShack and you should be able to find it there. You may also pick up some wire and cigarette lighter adapter.

Make sure to watch for polarity when you build the adapter.


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nice, thats very helpful – Adam Dec 14 '12 at 22:00
Good point. Polarity is important. It is usually shown on the back of the original wall adapter. – Hair_of_the_Dog Dec 14 '12 at 22:03
so after i check the original spec, i need to buy a barrel connector with the right polarity? or is it just how i connect the wires to the split wires? – Adam Dec 14 '12 at 22:59
i think i get it... the center pin is positive and surrounding shield is negative in the image on the left, reversed for pic on right, which should be on the ac wall adapter or back of device – Adam Dec 14 '12 at 23:01
Barrel connectors don't come in different polarity. You determine the polarity the way you connect it. – Chetan Bhargava Dec 15 '12 at 5:11

If it needs 12V it needs 12V. You should be able to replace it with anything with similar rating. Check the back of the wall adapter and check the current rating as well as the 12V rating you already know. Anything with a higher current rating than the wall adapter should work. Even a low current rating might work, but it should be pretty close.

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I cant seem to find any 12v cigarette adapters that plug into different barrel connectors (the normal 12vac plug on the back). I know i am being stupid here, but i just dont grasp it for some reason. So i just need a 12v car adapter basically. – Adam Dec 14 '12 at 21:03
will that work? Doesnt spec amperage, but it will take what it needs to from the battery amperage right? – Adam Dec 14 '12 at 21:13
12vac output? Are you sure it isn't 12vdc output? The Roadpro adapter you posted would probably work if you need 12 volts DC, which I would think you would. Remember to look at Chetan's post about polarity. – Hair_of_the_Dog Dec 14 '12 at 22:05
you are right... yes i meant to say the plug into the back gets 12vdc, after converted from 110 AC adapter n stuff – Adam Dec 14 '12 at 22:58

Both answers above miss the fact that 12v systems in vehicles are not 12v - they can vary from <10v under cranking to over 14v when the engine is running & the battery is being charged.

Some equipment will not care about this, some stuff will be relying on a well-regulated wall-wart to provide a steady 12v.

If you don't know which side your device falls, or it does need regulation, the best thing you can do is buy a decent quality regulated in-car adapter / power supply, they're not expensive and are available with interchangeable tips.

Heed the advice above about checking polarity, if in doubt, measure it with a multimeter before plugging in!

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