# power cables for 12v inside uses



## buck_1one (Nov 26, 2004)

I have noticed almost all of the small gadgets in the house have a 12v DC usage. My emergency radio, modem, router etc. I am in the plans of putting together a home weather station and started thinking about powering it all with a small solar setup.

So my question involves the different male and female power cables to these gadgets. Does anyone know if these are made to be tied into a battery bank? I know I can buy the different pieces and solder it all together myself, I was just hoping not to have to do all that. *I also don't want to cut up the power supplies that came with the gadgets,* just encase they are needed for some reason in the future.

Thanks for any help,
Buck


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## Bearfootfarm (Jul 13, 2006)

If they can run off a cigarette lighter plug, they are typically 12 volts with the amperage controlled by a fuse in the male plug. Some convert the 12 volts to a lower voltage too.

If they run off a 120 volt to 12 volt "wall wart", the amperage is controlled by the transformer.

You can run heavy duty wires to cigarette lighter type outlets mounted on or in your walls or baseboards to operate those types. The outlets are easy to find at Marine or RV supply stores.

You can also buy male plugs that have a variable amperage or voltage outputs so one plug can power different items as needed. The amps and wattage/voltage will be on each accessory

http://www.powerstream.com/dc6.htm

You might find it easier to use your solar set up to power an inverter since it's more efficient to run AC current if it needs to go very far.


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## stanb999 (Jan 30, 2005)

Bearfootfarm said:


> You might find it easier to use your solar set up to power an inverter since it's more efficient to run AC current if it needs to go very far.


AC is no more efficient than DC. The conversion losses are the big issue. 

Stay DC if possible. Going with 48 volts or higher is much better for moving the power around tho. Smaller wires and less effects from voltage drop. If you look there are a great number of devices that run on 48 volt native and lots of cheap solid state buck converters to fix the voltage to 24V or even 12v if needed at the point of use.


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## Gary in ohio (May 11, 2002)

I run a 12v only system. Biggest issue is power transmissions. I had to go to 0 guage wire within the house to keep the voltage drop to a minimum. MOst devices dont care if its 13.8 or 12v but I had some that did. Most Wallwart driven devices can be used on 12v. I use a "mobile" power supply for my laptop. My router runs directly from 12v, I have a TV that uses 12v, some of the other devices run on 12 so those 12v 5v chargers for cell phones can convert the power pretty cheaply.


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## Nimrod (Jun 8, 2010)

A particular device will usually have the volts it runs on and either the amps or watts it uses, embossed in the plastic or on a sticker. If not, and it uses a wall adapter, the amperage the adapter puts out may be listed on it. This is not what the device uses but is more than it needs so you are safe in using that figure for that device. An "A" with an "m" in front of it is milli-amps, thousandths of an amp. 

You can use the formula, volts X amps = watts, to figure out one if you know the other two. We want to know the amperage each device uses. Note that a device with a motor may need 2 to 3 times the amperage listed on it to start.

The sum of the amperages of the devices on a circuit, the voltage, and the length of the wire run will determine the size of the wire needed. Be sure to use a wire sizing chart for 12 volts. You also have to be careful not to exceed the capacity of the plug and socket you are using. A cigarette lighter socket may be capable of handling up to 10 amps at 12 volts. I once put too much on this type of outlet and it heated up and started to melt.

You have to have the polarity right or you will get the magic cloud of smoke. The polarity is usually listed on the device or the adapter. Normally the center contact of the plug is + and the outer is -. Same with the cigarette lighter plug and socket. I have used a standard 15 amp, 120 volt AC outlet to connect the fish house's 12 volt electrical system to the battery I bring out when I go fishing. It's polarised. Be careful where you use these because you don't want to plug a 12 volt device into 120 volt AC power. A multimeter is your friend here.

You might check your local pawn shops and electronics stores for unused ac adapters with the right connection for a device. They can be had for a buck or less.

I look at things slightly differently than BFF (no, I don't mean he's my best friend forever). A fuse does not regulate the amperage, it limits the amperage. An adapter does not regulate the amperage, it limits the amperage because it can only put out just so much.


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## Bearfootfarm (Jul 13, 2006)

Nimrod said:


> I look at things slightly differently than BFF (no, I don't mean he's my best friend forever). A fuse does not regulate the amperage, it limits the amperage. An adapter *does not regulate the amperage, it limits* the amperage because it can only put out just so much.


This is what I said:



Bearfootfarm said:


> If they can run off a cigarette lighter plug, they are typically 12 volts with the amperage* controlled* by a fuse in the male plug. Some convert the 12 volts to a lower voltage too.
> 
> If they run off a 120 volt to 12 volt "wall wart", the amperage is *controlled* by the transformer.


"Regulate" would imply it somehow changes something.
"Controlled" is the same concept as "limits".


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## Nimrod (Jun 8, 2010)

Bearfootfarm said:


> This is what I said:
> 
> 
> "Regulate" would imply it somehow changes something.
> "Controlled" is the same concept as "limits".


I mis-remembered the word you used but "controlled" and "limits" are not the same. If something is controlling another thing then it can set that thing anywhere from zero to the maximum. If something is limiting another thing then the other thing is free to be at any level from zero to the the maximum limit imposed on it by the something. 

In any event, this is not a hill worth dying on.


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## Bearfootfarm (Jul 13, 2006)

Nimrod said:


> I mis-remembered the word you used but "controlled" and "limits" are not the same.





> syn·o·nym
> [ˈsinəˌnim]
> NOUN
> 
> a word or phrase that means exactly or nearly the *same* as another word





> *con·trol*
> [kənˈtrōl]
> VERB
> limit the level, intensity, or numbers of
> ...





> *lim·it*
> VERB
> 
> set or serve as a limit to
> ...


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