Engineers - how do I make my VDO clock run on a household battery

[RichMason]

I'm going to pretend this is from my 911 so Wayne won't deep-six it. I have a VDO clock that is the last remaining piece of a car (911 of course) with great sentimental value to my wife. I want to mount it in a box of some sort and give it to her for our anniversary (yeah, I spare no expense). In any case, I need to know how I can wire it so it will run on a nine-volt or AA battery instead of a 12 volt car battery and keep the correct time. It has one positive wire going to a male spade into the back of it and I guess it was grounded through the dash harness somehow. Any suggestions?

[jazzbass]

It should be pretty simple and I think you have a good idea of what you need to do - first get 12 volts (8 1.5v batteries - AAA, AA, etc - or a 9v and 2 1.5v batteries). Go to RadioShack and get the appropriate holders. Solder them together. The case of the clock is ground (-), the one wire coming out the back is positive. I'd recommend investing in a $10 voltmeter from said RadioShack to make sure you're voltage and polarity are correct if you're unsure.

[RickM]

Chris, Would the 9v battery have enough current to run the clock?

If not or if you want to use less than 8 batteries you may be able to go to Radio Shack and pick up a 12v wireless garage door opener battery(used for the the outside keypads).

-or-

Use an inexpensive AC adapter and forget about batteries.

I'd be interested to know how it works out.

[jazzbass]

I don't think a typical VDO clock draws that much current, so a 9v would probably be OK. That said, I do like the 12V adapter suggestion better - I hate changing batteries all the time.

[Joeaksa]

Go to an electronic store and get a surplus charger unit for something that inputs 110vAC and outputs 12vDC. Lots of toys and likewise use this type of charger.

Plug the puppy in the wall and put the positive lead to the lead on the clock, and the negative lead to the lead on the case. Works fine! I have done this for testing several times and worked for days while I was calibrating a clock.

Here is a whole page of them:

http://sales.goldmine-elec.com/prodlist.asp?catid=2077

Here is a heavier duty version for under $3:

http://sales.goldmine-elec.com/prodinfo.asp?prodid=2976

Never used the above company but found them on a web search.

Joe

[Porschedude]

How much room do you have? Are you going to build it into a wooden case?

If you want it stand-alone, then you might try an UPS (Uninterrupted Power Supply) battery. They are 12v sealed lead acid type. You would still need to charge it once in a while. The one I just saw was $12 and measures 4.21"H x 3.54"W (4AmpH), x 2.76"D. I found it at www.batteries.com . The P/N is 292944, or another is 4"H x 6"W, x 3"D (7AmpH), $18, P/N 292945.

I think I build one as a Dad/Kid project...

Keith

[Joe Bob]

Don't know if they work....but I've seen ads that show a 9v battery hanging off of a cigarette insert that supposedly keep the presets active if you insert prior to disconecting the main battery.

Bet ya JC Whitless has them, or most of the local parts stores have a source....

[pwd72s]

Maybe a peek at motorcycle batteries? But really, I'd think a quartz clock would run a LONG time on a pack of 8 1.5V AA size...and I know Radio Shack sells the holder that connects them to produce 12V...I've bought 'em.

[GT911]

Introduce your wife to big Optima gell cell battery, after she develops a sentiment for it your problem is solved.

Just kidding, use the 12v power adapter for power, it will be a cord, but a very small one.

Get a piece of aluminum about 4” wide by 7”, round the top off and punch a hole for the clock, then put a 100 degree bend about 3” from the bottom to form the base. Polish to a high luster, and if you want to be really creative take it to a jeweler and have it engraved with just the right words.

If you really want some points make it out of acrylic, and polish the edges and engrave it. Then take the clock apart and chrome plate the back part.

It will look like a trophy, perfect for any setting.

[pwm74]

use a old cell phone house charger.

I was toying with this idea and was going to use birch, moghany, oak block and stain. make a big hole like the 911 dash and a little one in the back for wire lead. one on top for a button to turn on the light for the dark. OOOOHHHH Lala