What kind of power?

Netdewt · 4th January 2011, 10:32 PM

Nooby question, but I don't want to screw this up.

I have a clock from a car I want to make into a desk clock. I am assuming it runs off of the 12VDC power in the car, like most accessories do. What kind of power should I set up? How many amps?

bob91343 · 5th January 2011, 12:02 AM

Almost no current, maybe a few milliamperes. Any wall wart will work but it's best to err on the side of too little voltage rather than too much. A 9V unit ought to be about right, and they proliferate.

Else you can run it off batteries.

PedroDaGr8 · 5th January 2011, 04:20 AM

Don't forget if it is drawing too little load, many wall warts are unregulated which means their output can get really high at low loads. So looking for a 12V regulated wall wart would be better.

dangus · 6th January 2011, 08:25 AM

If it's a vacuum fluorescent or LED display, it'll pull more than just a few mA. I'd try a 1A regulated supply; that's often used for scanners, cable modems, and USB hard drives.

If you're building the clock into a larger case, why not add a lighter jack powered from the 12V. Then you can use car adapters to charge cell phones or MP3 players or GPS or ?.

davidsrsb · 6th January 2011, 01:26 PM

9V dc nominal unregulated should work fine. Car electrics run at 14V when the engine is running.

Netdewt · 3rd February 2011, 02:39 AM

Quote:

Originally Posted by dangus

If you're building the clock into a larger case, why not add a lighter jack powered from the 12V. Then you can use car adapters to charge cell phones or MP3 players or GPS or ?.

Cool idea! I have one of those lying around also. It is an analog clock that is backlit.

dangus · 4th February 2011, 04:48 AM

Some old analog car clocks used an electric motor to periodically wind up the spring that ran the clock. A more modern analog car clock would use a quartz crystal controlled movement that consumes negligible current, except for the backlighting.

Netdewt · 4th February 2011, 02:30 PM

I'm guessing it's in the modern category... 90's.

4th January 2011, 10:32 PM	#1
Netdewt diyAudio Member Join Date: Jan 2010	What kind of power? Nooby question, but I don't want to screw this up. I have a clock from a car I want to make into a desk clock. I am assuming it runs off of the 12VDC power in the car, like most accessories do. What kind of power should I set up? How many amps?

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5th January 2011, 12:02 AM	#2
bob91343 diyAudio Member Join Date: Mar 2010	Almost no current, maybe a few milliamperes. Any wall wart will work but it's best to err on the side of too little voltage rather than too much. A 9V unit ought to be about right, and they proliferate. Else you can run it off batteries.

5th January 2011, 04:20 AM	#3
PedroDaGr8 diyAudio Member Join Date: Dec 2009 Location: San Diego, CA	Don't forget if it is drawing too little load, many wall warts are unregulated which means their output can get really high at low loads. So looking for a 12V regulated wall wart would be better.

6th January 2011, 08:25 AM	#4
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	If it's a vacuum fluorescent or LED display, it'll pull more than just a few mA. I'd try a 1A regulated supply; that's often used for scanners, cable modems, and USB hard drives. If you're building the clock into a larger case, why not add a lighter jack powered from the 12V. Then you can use car adapters to charge cell phones or MP3 players or GPS or ?.

6th January 2011, 01:26 PM	#5
davidsrsb diyAudio Member Join Date: Dec 2005 Location: Kuala Lumpur	9V dc nominal unregulated should work fine. Car electrics run at 14V when the engine is running.

4th February 2011, 04:48 AM	#7
dangus diyAudio Member Join Date: May 2004 Location: Vancouver Island	Some old analog car clocks used an electric motor to periodically wind up the spring that ran the clock. A more modern analog car clock would use a quartz crystal controlled movement that consumes negligible current, except for the backlighting.

4th February 2011, 02:30 PM	#8
Netdewt diyAudio Member Join Date: Jan 2010	I'm guessing it's in the modern category... 90's.

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