# Hooking up your house to 12v



## jsriley5 (Sep 22, 2012)

OK the grid is down and you don't expect it to come back for a long long time. 

Can you hook a couple 12v batteries up at the Breaker box and feed 12v into your houses existing wiring? I Don't mean to try to run it normally. I know appliances meant for 120 aren't going to work and will need to be unplugged or disconnected or the breakers pulled for that circuit. But using the original wiring should allow you to use 12v bulbs (not efficient but Im not sure regular incandescent won't still work 12v) there are many led or 12v florescents out there so your regular lighting and switches could be used. Any of the qv appliances could easily have their ends replaced to work in regular outlets so you can plug in your chargers, and I suppose even 12v coffee makers fans and stuff. It would seem to be convienient so what am I missing. Not an electrical engineer but I have done a fair bit of vehicular wiring and household wiring. What I don't know is what makes a 120 breaker a 120 breaker would those have to be bypassed. I don't see this mentioned so I must be missing somthing. 

Anyway was just thinking I can have my portable rolling cart with the solar panels I can set it out to charge all day while we are out doing our outside chores etc. then at night roll it in and hook it up and we'd have minimal but somewhat normal electrical use for 4 or so hours before we knock off to bed and any gear needing charging can stay charging plugged in at the bedside ready to hand. Then repeat get up make a pot of coffee in teh 12v drip maker then un hoook and put it out to charge. Could even rotate with the batteries charging on the wind unit or leave a couple set up all the time constantly charging from a wind unit and just boost it at night with the portable solar unit. anyway you get my idea. Heck could even get some 12 appliances too if power supply gets ahead of the more basic need. OK no more rambling I'll submit it for comment.


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## labotomi (Feb 14, 2010)

Yes, but the wiring is sized for 120V. To get the same power from 12V takes 10X the current which could overheat the wiring and cause melting/shorts... fire, death, destruction, pestilence etc.

Incandescent lights don't care if it's AC or DC. Florescent lights will work on DC, but the life will be significantly shorter and ones designed for 120VAC aren't going to be able to get the kick to run off of 12VDC


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## hiwall (Jun 15, 2012)

If you do decide to do this you should pull your electric meter so there is no chance of AC voltage coming thru. To pull the meter, remove the band and pull.


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## Caribou (Aug 18, 2012)

You might also want to consider an inverter. These are available in various sizes to fit your needs. There is also more voltage drop on DC over distance that is why we use AC. For cars, boats, and other small area applications 12V is fine. I know people that have wired small remote cabins with both 12V and 120V. These are two totally different systems with different plug types and no crossover. Get a book on 12V wiring or boat wiring. Each wire run will need to be calculated for wire size depending on load and distance of run.


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## Ridgerunner (Oct 27, 2008)

I am planning to use an inverter.
I am currently bulding a 12v Generator that will be able to Charge a battery bank as a back up to the solar panels that I will have hooked up.

The 12 volt generate consists of a 6.5HP gas motor and a car Alternator. I am Stillin the planning mode for this.


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## zombieresponder (Aug 20, 2012)

Ridgerunner said:


> I am planning to use an inverter.
> I am currently bulding a 12v Generator that will be able to Charge a battery bank as a back up to the solar panels that I will have hooked up.
> 
> The 12 volt generate consists of a 6.5HP gas motor and a car Alternator. I am Stillin the planning mode for this.


6.5HP is way overkill for an automotive alternator, unless you're talking about some sort of a really high output alternator.

Volts x amps = watts.

12V x 100 amps = 1200 watts

746 watts = 1 horsepower

1200W / 746W = 1.6hp

I would round that up to 3 hp for the motor to account for various inefficiencies and call it good.


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## jsriley5 (Sep 22, 2012)

Yes I would of course remove the meter should have mentioned that I can just imagine how fast my batteries would drain feeding back into the lines. I would probably disconect the lines in from the breaker box as well no sense having the potential drain there. 

So should skip the high draw appliances then and stick to LED type lighting and I would think I could still charge small items like kindles, and laptops. Just have to make my coffee out at the source (which is hypothetical as I don't even have a 12v coffee maker) I really don't have any high drain appliances I spent most of my efforts in reducing the need for electric as much as possible. But the convienience of light when you flip a switch and the easy recharging of portable electronics like my laptop I:m using and have lots of stuff stored on and my kindle which has a large and growing library of refference books are just too nice to want to do without. And yes I can do it all on the cart but darn it I don't wanna fall that far back if I can help it. Hopefully once we get moved and settled I can start improving my wind solar systems and perhaps add proper 12 house supply and get actual appliances to run off them like refridgerator and deep freeze. Those two items would definitely move things out of the surviving to the thriving raNge. I would miss my iced drinks, have done without and it's easy enough to do but I miss it every drink I take. and the easy storing of left overs just can't be beat. And cold milk oh my goodness I"m soo spoiled.


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## CulexPipiens (Nov 17, 2010)

jsriley5 said:


> Yes I would of course remove the meter should have mentioned that I can just imagine how fast my batteries would drain feeding back into the lines. I would probably disconect the lines in from the breaker box as well no sense having the potential drain there.
> 
> So should skip the high draw appliances then and stick to LED type lighting and I would think I could still charge small items like kindles, and laptops. Just have to make my coffee out at the source (which is hypothetical as I don't even have a 12v coffee maker) I really don't have any high drain appliances I spent most of my efforts in reducing the need for electric as much as possible. But the convienience of light when you flip a switch and the easy recharging of portable electronics like my laptop I:m using and have lots of stuff stored on and my kindle which has a large and growing library of refference books are just too nice to want to do without. And yes I can do it all on the cart but darn it I don't wanna fall that far back if I can help it. Hopefully once we get moved and settled I can start improving my wind solar systems and perhaps add proper 12 house supply and get actual appliances to run off them like refridgerator and deep freeze. Those two items would definitely move things out of the surviving to the thriving raNge. I would miss my iced drinks, have done without and it's easy enough to do but I miss it every drink I take. and the easy storing of left overs just can't be beat. And cold milk oh my goodness I"m soo spoiled.


A chest freezer rewired to run as a refrigerator pulls very little power, usually 200 watts or less per day. (Google for more, here is one http://www.aselfsufficientlife.com/...on-the-most-energy-efficient-fridge-ever.html) You can also get small ice makers (about half way down the page http://www.solar1234.com/).

Charging up a couple of modestly sized batteries along with some careful selection of appliances can make your idea quite feasible, just probably not via your existing wiring.


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## cowboyhermit (Nov 10, 2012)

It will work but is not to be considered "safe"
I would lock out the power at the pole for sure, not to avoid a drain on your batteries but to avoid someone getting killed. Any ac power will go back into the grid and be converted up by the transformer to 1000/10000volts or what have you. Dc should not but if the power were to come back on, anything hooked up on your end would be in trouble. Also consider if the power company comes by.
AC and DC breakers are different and you shouldn't use them with DC. The wiring however is sized by ampacity and that doesn't change, so a 15 amp circuit can handle 15 amp dc as well. Consider some cheap in-line fuses.
What you have done with finding ways of using less power sounds great, laptops are much better than most tvs or desktops.


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## labotomi (Feb 14, 2010)

cowboyhermit said:


> AC and DC breakers are different and you shouldn't use them with DC.


I'd agree if her were using a higher DC voltage, but he's mentioned a car alternator powering batteries. The potential of 12V causing ionization and a continued arc is very remote.

Now the exception is if the breakers have electronic trip units. Those would have to specify AC, DC or Both. These are used in industrial settings, but not (normally) in homes. Those types would not necessarily recognize the increased currents due to the way current is sensed.


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## sgtrunningfool (Dec 8, 2012)

You should listen to the two part series on this topic on the survival blog psot


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## jsriley5 (Sep 22, 2012)

Thanks all I appreciate the thoughts and discussion. Do keep in mind I was talking about teotwaki and the grid ain't coming back so while pulling the meter is an important step there would be little worry about the electric company coming by. I wouldn't bother with this for short term or even just a month of power outtage.

So let me throw another thought out. could you take a soldering iron and handful of bright led bulbs and some old incandescent bulb bases and soderthem together to make leb bulbs? Then cast somthing dense to absorb heat and protect the led like say rock hard plasticized wood puttyaround the whole thing above the base. If I looked for and found 12v Led's it would seem intuitively that it should work and would or should work out much more cheaply than trying to buy the led bulbs. The last ones I tried did not have good heat sinks did not last long and weren't all that bright. Yeah what I get for buying cheaply. You can somtimes find bulk packs of cree led's the bright ones it's been a while since I looked but they were relatively inexpensive and put out lots of light would just need a diffuser of some kind. need to look and make sure they dont also require circuitry to moderate power but even at that I could possibly buy the led lighting like is used on comercial trucks already wired for 12v. Could even have some red that way for light discipline issues if things are ugly.


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## cowboyhermit (Nov 10, 2012)

Pretty sure there aren't any 12V leds, they can be wired in series, or use circuitry to run on 12V. Slowly, white automotive leds are becoming reasonable, much more slowly than other colours. My favorite cheapo ones have been licence plate lights, so far. Even interior (vehicle) led lights are overpriced at this point imho.
If you want to do the wiring I would recommend getting the right stuff, thermal paste, epoxies, etc are all pretty reasonably priced and made to withstand heat and not burn. Something like wood putty you never really know.
Haven't seen the numbers but running led lights on AC with an inverter might be more efficient than using dc directly because they are only on 60 times per second. Usually I am all for using dc directly but if you are intent on using existing wiring and sockets it might make sense.


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## labotomi (Feb 14, 2010)

12VDC LED Selection

This doesn't mean the LEDs themselves run on 12V as many times there are circuitry to lower the voltage to the necessary levels needed. I don't think you can just buy LEDs and hook them up to 12Vdc and be done.

Those with an E27 Base are standard for North American fixtures. Keep in mind that you need about 450 lumens to equal the same output as a 40W incandescent.

You can use this to design your own circuit if you know some basic specs of the LEDs

http://ledcalculator.net/


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## cowboyhermit (Nov 10, 2012)

Just to clarify, the highest voltage of an led I have seen is less than 5 volts. The 12V ones that were linked above are multiple led "bulbs" with circuitry to protect the individual led's from being "overdriven". If you get bulk led's they can be a great deal but you should know that for 12V you will need to have some way of regulating their power. If you use little batteries it is a lot easier, button cells in particular, but that is not really what you are looking for, I am thinking.


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