120 to 12 volt???

[badger08]

This winter I'd like to build a work bench lamp using dash parts from a John Deere tractor. I will take care of the build and my uncle is going to wire it up for me as he's an electrician. I kind of want to know what I'm up against before I build it, so I make sure there is enough room for the wiring, etc.

But is there a way to convert back to 12 volt? The reason why is I want the light in the dash to light up to. I think it would be neat to have it like on the tractor where you can have 3 or 4 different settings. So for instance I could run just the dash light, dash light and bigger lights, just bigger lights, so on. That dash light is 12 volt, or is it best to just retrofit it somehow? Sorry but I've never been one to mess much with electricity!

I found this when searching 120 to 12 volt converter:

http://www.ebay.com/itm/Power-Max-RV-Converter-Battery-Charger-PM3-45-AMP-120-V-AC-to-12-volt-DC-Supply-/301409709331?hash=item462d6b2d13&vxp=mtr

This is somewhat what I will build:

http://machineagelamps.com/products/steampunk-lamp-john-deere-farm-11-jd-2

Any advice is appreciated!!

 

[trainer]

A 15 v. walll wart adapter. Old laptop charger or printer power supply, Door-bell transformer, inexpensive 12 volt battery maintainer.
the e-bay one looks like it would be overkill.

 

[larry_g]

A low voltage outdoor lighting transformer would do the job. Look at them at HD or Lowes. vYou have to figure out the wattage of the lamps you wish to light and have a transformer rated just a bit higher than your total wattage.

lg
no neat sig line

 

[fourjeepin]

I use an old 12 volt wall wart for powering things such as this. They are small and inexpensive (if not free/scavenged)

 

[Mgraves235]

Very easy to do, you could build a basic circuit with a Xfmr with Radio Shack parts and very little skills needed. Plenty of diagrams on the web. A transformer to step down the voltage and a rectifier to change it from AC to DC.

The idea of using an old wall wart adapter is a good one, as that would most likely be free. Plenty of 9-18 volt wall warts and laptop adapters out there in junk drawers.

You could also use an old PC power supply, if you happen to have an ancient pc you haven't gotten rid of yet, but would be overkill and bulky for what you need.

 

[joe_padavano]

Type 12 volt power supply into Google. There are about a bazillion of these for sale in the $6 to $12 range. It isn't worth your time to invent something half-@$$-ed.

Of course, the real question is, why don't you want to simply rewire the lamp with a 120 lamp socket and be done with it.

 

[Norcal]

A 120 volt pri, 12 volt sec. transformer should be easy to find, you don't need DC for your application.

 

[badger08]

I don't mind rewiring it if that is the feasible thing to do, it's such a small bulb in the dash light though didn't know if it would generate to much heat or how that works.

I will look into all the recommendations and do some research before the project.

The link lamp just has the top light working, I want the light working above the gauges to actually work, just like the real thing (as I have the same tractor that dash is from so that's why I'd like it this way). Thanks for the replies and I will look into them!!!

 

[Shiftless]

Converting to run on house current would require finding a 110 volt bulb with the same base or finding a small enough bulb and appropriate socket to mount inside the guage assembly. Also you would need better wire insulation with the higher voltage.
If I were you, I would go with the transformer idea. Get a small Malibu landscape lighting transformer. As others have already said, make sure to add up the wattage of your guage bulbs and then make sure your transformer is rated for at least that much load and a bit more. The little wall wart transformers might not be up to the task of powering 3-4 bulbs at the same time. Check the watts sometimes called VA. Remember your high school science class where you learned that Watts = Volts x Amps. The smallest Malibu transformer should have plenty of capacity. Remember though that it will give you alternating current so you can't use it to charge batteries!

 

[G_P]

Light bulbs dont care if the voltage is AC or DC. A cheap doorbell transformer will get you somewhere a little over 12v AC and will light up bulbs just fine.

 

[hifi_hokie]

Radio Shack used to grow these on trees, from 275mA up to a few amps at 12VDC.

 

[Shiftless]

Light bulbs dont care if the voltage is AC or DC. A cheap doorbell transformer will get you somewhere a little over 12v AC and will light up bulbs just fine.

Badger:
If you decide to try a doorbell transformer, check on the voltage...most of them are 16 volts up to as much as 24 volts. Your bulbs will be extra bright but will not last very long at all. If you don't have a meter, I suggest you get one. They come in handy.

 

[G_P]

A 16v should be fine. The load of a few bulbs will probably cause the voltage to drop down a bit, and automotive components can take close to 15v.

A 24v will result in bulbs that shine like the sun but burn out in seconds.

If steady voltage at high load is desired, just grab any random old desktop PC you can find and yank the power supply. Instructions can be found easily online that will show you how to get it to turn on outside of the PC case. Those will give you a regulated 12v with more than enough amperage to run all the bulbs you want.

 

[Shiftless]

A 16v should be fine. The load of a few bulbs will probably cause the voltage to drop down a bit, and automotive components can take close to 15v.

A 24v will result in bulbs that shine like the sun but burn out in seconds.

If steady voltage at high load is desired, just grab any random old desktop PC you can find and yank the power supply. Instructions can be found easily online that will show you how to get it to turn on outside of the PC case. Those will give you a regulated 12v with more than enough amperage to run all the bulbs you want.

This is the best idea yet.

 

[trainer]

If you have a 24v transformer, wire the bulbs in series, in groups of two, or use 6 volt bulbs with 4 in series.

Another option would be to use 120v christmas tree mini-lights and sockets adapted to fit in the guages. You could even use coloured lamps for extra effect.

 

[rsanter]

So do you still need the 110v to power the lamp light but you want a lower voltage to power the lights in the dash piece?
If so I would just use the mini neon bulbs as they can handle the 110v and still not give off too much heat

Bob

 

[Shiftless]

If you have a 24v transformer, wire the bulbs in series, in groups of two, or use 6 volt bulbs with 4 in series.

Another option would be to use 120v christmas tree mini-lights and sockets adapted to fit in the guages. You could even use coloured lamps for extra effect.

Has anyone wired 10 twelve volt lights together in series and run them directly off of house current with no transformer? In theory, it should work fine. Of course if just one of them burns out the whole string will go dark and you won't know which one is dead without testing them individually

 

[hifi_hokie]

A 16v should be fine. The load of a few bulbs will probably cause the voltage to drop down a bit, and automotive components can take close to 15v.

A 24v will result in bulbs that shine like the sun but burn out in seconds.

If steady voltage at high load is desired, just grab any random old desktop PC you can find and yank the power supply. Instructions can be found easily online that will show you how to get it to turn on outside of the PC case. Those will give you a regulated 12v with more than enough amperage to run all the bulbs you want.

When I was in car audio, guys would sometimes run non-isolated 16V systems in an attempt to ease current requirements for massive amplifiers (4-5kW). 16V was typically tolerated, but it used to be funny to watch things fail when they'd get greedy and adjust their regulators for 18V...