# Reducing 12 volts down to 9 volts



## NJ Rich (Dec 14, 2005)

I use a table lamp with a 12 volt light bulb during power outages. This has been covered in another HT thread in to last two days concerning oil lamps..

My question is how do I reduce the 12 volts from a deep cycle battery down to 9 volts. I have several 9 volts radios and want to use them for weather information; public alerts and entertainment during power outages.

Yes.... I went to my local Radio Shack and the people there were clueless. :shrug: I am not an electronics guy. I can build you a big building but electrical systems are out of my league. :help:

I went on-line and looked for info but that was another can of worms. I need specific info about "exactly what resistors to use and how many and on what wires".  Yes., I can solder and runs wires and not burn down the ranch. So guys and gals what do I do and how? :help: Any help will be greatly appreciated. NJ Rich :bouncy:


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## wy_white_wolf (Oct 14, 2004)

DC-DC converter

12V to 9V, Step-down, 2A, 20W 12V to 9V dc-dc converter [] - $10.50 : Current Logic, Expert of DC-DC Converter


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## rancher1913 (Dec 5, 2008)

actually if its just the lamp you want to change all you need to do is hook it up to a 9 volt power source, the 12 volt bulb will work just fine--it will be dimmer than with 12 volts but it won't hurt the bulb, its when you go up in voltage that damage occurs, like using a 6 volt lite with a 12 volt source.


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## rancher1913 (Dec 5, 2008)

sorry just understood your actual use. what wy whit wolf said.


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## spacecase0 (Jul 12, 2012)

how much current is your 9V item pulling ?


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## NJ Rich (Dec 14, 2005)

The closest amp draw wen site information I can find for a 9 volt/110 ac powered radio is 1.5 amps.


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## spacecase0 (Jul 12, 2012)

I bought 10 of these 
LM2596 DC Step Down Buck Volt Converter Circuit 3 2 40V to 1 25 37V Regulator | eBay
don't know if they were from that seller or not, but lots of sellers have them.
I got them to convert the 22V peak out of a solar panel to run my radio that runs on about 7V nicely, and also use them to convert whatever voltage the solar puts out to a 13.8V to charge my car battery. they are easy to adjust the output voltage and are quite efficient.
the LM2596 based converter boards work very well, work up to 2A with no heat sink, and 3A for a short time or if you heat sink the chip, and are only a few dollars


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## farminghandyman (Mar 4, 2005)

at one time they made converters that would plug in a cig lighter that you could get 6, 9, or 12 volts by sliding a switch and had various cords to go into the power plug,


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## rockhound (Sep 25, 2009)

Google for "ballast resistors" and read until you have a good understanding of them, then go to a auto parts place and get one.


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## Robotron (Mar 25, 2012)

Google Lm317 ic chip. Very few components to make a very functional adjustable regulator that will supply 1.7 amps. $5 and done.


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## farminghandyman (Mar 4, 2005)

Like I said they made them for cars, and still do,

https://www.scannermaster.com/RadioShack_9_Volt_Charger_Straight_Cord_p/22-531132.htm

12 volt to 1.5, 3, 4.5, 6, 7.5, 9 volt switching DC/DC converters with 2 amp output car adapter.

Â» Medela 9 Volt Lighter Adapter &#8211; Medela 67174

http://www.amazon.com/Medela-67153-Car-Lighter-Adapter-12-Volt/dp/B000058DPL/ref=cm_rdp_product

Electronics Plus - Hard to find parts and accessories, available and ready to ship!
this is similar to what I have,
Minute Man Electronics Automotive DC to DC Converters
cigarette lighter clip on, or one could just get a multiplier and wire it in, 
RoadPro - RPPSAPS - 12-Volt Clip-On Battery Platinum Series Cigarette


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## coup (Feb 28, 2007)

just run the battery down to 9 volts and there after just charge to nine volts....


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