Instructables
Picture of Solar Hurricane Lighting (and more)

I've spent my entire life living on or near the Gulf Coast. And even though we've had a couple of seasons with no major hurricanes, I can't help thinking about them this time of year. Of course, the big storms are very dangerous and most people should evacuate to safer ground. But those who stay and those who return afterward, are often faced with a loss of electrical power. Even some relatively minor storms can cause power outages.

Power outages suck! Sure we have candles, lanterns, and flashlights, but you have to either station these items in each room or carry them around with you. I was trying to think of some way to have lights in every room of the house in the event of a power outage and, naturally, solar came to mind.

I would love to outfit my house with a complete solar system that produces 5 or 10 kW of power, but I'm not quite ready to make that investment. So I needed a quick, easy way to have lights all over the house, plus the ability to run other small devices such as fans and a couple of phone chargers.

I was walking around my house from room to room thinking about this and it hit me; phone jacks! Even though I haven't had a landline phone in years, there are phone lines run throughout the house and a handy little wall jack in each room. Why couldn't I use this wiring to provide low voltage solar lighting in the event of a power outage?

Well, the first reason is I didn't know if I could legally disconnect the wires inside my house from the phone company's junction box outside. So I called my local phone company office and asked. Turns out there's a customer disconnect right there on the side of the house. They said I can disconnect my house from their line and everything on my side is my property. Awesome!

The second reason is the wire size. Typical phone cables are between 22 and 26 gauge, which means the current capacity is very limited. But I did some research and found that there are all shapes and sizes (and wattages) of 12 volt light bulbs out there and the LED bulbs come is sizes as low as 2 or 3 watts.

Based on the information I found at http://www.engineeringtoolbox.com/wire-gauges-d_419.html I should be able to safely run 3.5 amps through a 24 gauge wire. At 12 volts, that comes to 42 watts. However, since I don't know the length of the wire in the walls, I decided to play it safe and keep it to a maximum of 2-3 amps, which still gives me 24-36 watts to work with.

So I decided to configure a low-end solar system using mostly items I had on hand or could buy locally. What follows is a detailed description of this project. I hope you like it!

UPDATE: I added an inline fuse between the charge controller LOAD (+) lead and the phone line just in case somebody plugs in too heavy a load.

UPDATE: Due to lots of helpful suggestions (and a few outright warnings) regarding my choice of a 110 volt plug for the power outlet, I decided to add some optional 12 volt outlets to the project. Please see Steps 1 & 3 for details.

 
Remove these adsRemove these ads by Signing Up
emachine563 months ago

Please visually inspect all the phone wires, splices, jacks and junctions you plan to use. There can be anything between 19g to 26g wiring with all kinds of splices in between. Telco premise wiring was never intended to carry more than 1A of current whether ringing @ 90-105VAC or idle with -48 to -52VDC of talk battery (at least in former BellSouth territory).

If the house was wired by someone other than the local Telco then you could have anything. I've seen 28g speaker wire to ROMEX used. This is a neat idea though. Please look carefully at everything and then revise as necessary and fuse everything as low as possible. I'm an old retired Telco guy and believe me, you don't want to bet the house on the quality of the phone wiring to carry anything over 1A, period. Hope this is of some value to all.

mikesoniat (author)  emachine563 months ago

Thank you for that information. I will definitely inspect my wiring more carefully and modify my design as needed.

Ernest123 months ago

I would never use a 120 Volt outlet as a 12 DC volt outlet. Someone is going to plug a 12 volt item into 120 volt ac circuit and cause major problems. Find an appropriate 12 volt DC plug and receptacle, and use it in your house system, and on any auto or boat so you can have options and above all safety. Also, I would use a 12 volt dry automotive battery, instead of those 12 Ahr alarm batteries. By using an automotive battery you have a backup to start a car, boat, or tractor. More options, more safety.

mikesoniat (author)  Ernest123 months ago

Please see my last update where I said:

Due to lots of helpful suggestions (and a few outright warnings)
regarding my choice of a 110 volt plug for the power outlet, I decided
to add some optional 12 volt outlets to the project. Please see Steps 1 & 3 for details.

adamfaal3 months ago

I do not agree with the comment saying that you should install heavier cables just because you might want to add higher load some time in the future. That kind of thinking creates a LOT of waste in the long run. Overloads should be handled by appropriate fusing.

In XP programming it is expressed like this, but applies to other areas as well:

http://www.xprogramming.com/Practices/PracNotNeed.html

KROKKENOSTER3 months ago

I am also playing around with this idea but I want to use the existing 240 lighting wiring and then use led lamps throughout . Here in South Africa we have "Power shedding" sometimes without warning. This will make the effort on wiring a lot simpler. The cost do come down and soon I think this will be standard way of doing!

jtechian3 months ago

As others have said, never use phone wire for power wire. It looks like you actually used bell wire for doorbells etc. , which may carry some power - but still always plan for a future use rather then immediate use. You mentioned possible a 110v inverter, and they can draw several amps (like 10 amp or better when loaded). So plan for the worst loads. Even for your small system you would be better off running 12 gauge or better 10 gauge wire for all the dc lines. I know its over kill now but you may like solar and decide to add more panels etc.

Thanks for the inspiring build and maybe move others to explore the benefits of solar.

mikesoniat (author)  jtechian3 months ago

The inverter will only be plugged in directly to the control box, not running over the phone wires. As I mentioned in the article, I only plan to use very low wattage lights (3 watts or so) in the house. I added a 3 amp fuse just in case I accidentally exceed that.

sb43 months ago

Here is an idea that may be controversial or not -- it would cost more, but maybe a fun challenge too. The idea is step up the voltage from the solar cells to a higher voltage for transmission through the phone wiring, then step it back down at the jack where it is used. This would allow more power transmission, less loss, through your wiring for the same current. DC-to-DC converters might be best to avoid radiating EMI all over the neighborhood, especially depending on the frequency you choose.

Although this works in theory, maybe the safety issues are too extreme. Actually, even the 12 volt system has safety issues in my opinion, since telephone wiring is probably not rated for significant currents and electrical codes for the wiring probably assume low power (not conduit shielded). However, the phone company did supply around 50V DC I think through that wiring (I don't know what power available), so maybe things are AOK at least up to 50V -- just need to keep the power in reason so a short in the walls doesn't burn your house down. Still, I'd be nervous repurposing telephone wiring for power uses in the end.

This is a great help to a project I plan to build. I have a garage 150 feet from any power source other than a portable generator. To just go into the garage and see where I am going especially at night I have to carry a flashlight and then start the generator for power for lighting. This very detailed instructable you have posted is a great solution. Thanks for sharing your ideas.

mikesoniat (author)  InventSomething3 months ago

You're very welcome! And thank YOU for your kind words!

shortw3 months ago

Your phone wire size and the thermostat wire is way to small for a 12 volt DC system and you will lose a lot of volts and amps while you put a load on it. DC does not like to travel far in an way undersized phone wire without losing voltage and amps under load.

What size of fuse are you using now?

The fuse is here to protect the wire, not the light. The size of fuse depends on the size of wire. And the wire size depends on voltage and amps and how many feet the power has to travel.

What about ground ?

And .....you put a ground wire on the solar panel and mounting rails/hardware and pounded a separate ground rod into the ground and connected your devices to the new ground rod?......right?

mikesoniat (author)  shortw3 months ago

I used a 3 amp fuse based on my calculations above (7th paragraph).

Mackramer3 months ago

Great project. Are you worried about the solar panels being ripped off the roof or damaged during the hurricane? Maybe keep them inside until after the storm passes?

mikesoniat (author)  Mackramer3 months ago

Yeah, I actually plan buy or build some brackets to secure them.

Thanks!

calebwang4 months ago

Awesome instructable! Once I own a house I'd love to try something like this.

mikesoniat (author)  calebwang3 months ago

Thank you!

mikesoniat (author) 4 months ago

UPDATE: Due to lots of helpful suggestions (and a few outright
warnings) regarding my choice of a 110 volt plug for the power outlet, I
decided to add some optional 12 volt outlets to the project. Please see Steps 1 & 3 for details.

spiritplumber4 months ago

I love this but I question using the same plug for 12V and 120V... I recommend you use car cigarette lighter plugs if you have them.

mikesoniat (author)  spiritplumber4 months ago

Thanks, I'm also considering PowerPoles.

http://www.powerwerx.com/powerpole-accessories/powerpole-outlet-cover-plate-electrical-box.html

One thing I have done for a project a while ago (Italian 3-prong plugs and sockets) was to connect the two outer prongs together, that being LIVE and NEUTRAL, and call that 12V+, and use the central EARTH prong for 12V-. The two outer prongs were connected together at the plug.

If someone plugged that into 220V, it'd immediately trip a breaker, and the high current would "stay" in the plug, so at worst, the plug would get burned rather than the device.

Just a thought.
carlos66ba4 months ago

I'd hate to be the guest to your home who connects one of your 12 V appliances to a regular 120 V wall socket... You need to definitely change the connectors. This is akin to putting poison in a coca cola bottle :)

Other than that, this is a superb project! Congrats!!

mikesoniat (author)  carlos66ba4 months ago

Thanks, Carlos! I probably won't have too many house guests during a hurricane, but I'm definitely looking at other options for the outlets.

One more suggestion: add fuses right after the batteries. If by any chance a cable shorts this can cause serious trouble (once I saw a car battery + touch the hood of a car, the result was a 1/2" hole in the metal hood).

mikesoniat (author) 4 months ago

UPDATE: I added an inline fuse between the charge controller
LOAD (+) lead and the phone line just in case somebody plugs in too
heavy a load.

wingman3584 months ago

Great project. I commend your ability to avoid going too big too soon. Along the same lines as captainchaoss, I wonder if you could have a separate plug and connector so there would be no chance of putting 115V across the 12V bulb. Perhaps when you bulk up your system you can look into that. It makes me wonder just how little power is required for daily electrical needs, such as lights, range, PC usage, etc. I bet it would be fairly easy to transition almost entirely (say 80%) over to solar power using 12V house-wide circuits. Might be more trouble than its worth converting all the appliances over to 12V though. What goes into stepping 12VDC up to 115VAC?

mikesoniat (author)  wingman3584 months ago

Thank you, WingMan! Yeah, I may be rethinking the 110V outlet in favor of a more standard 12V plug.

captainchaoss4 months ago

Thank you for an excellent Instruct-able ! I'm not at risk of a hurricane, and have a very stable power grid (so far) but have been wanting to do something similar. Your system is a great idea. Tho I have no land lines through my home any longer, it would be easier to run than regular lines.
my question is, rather than using 110 outlets and LEDs with socket bases, could I rig up d/c LEDs that connect in the phone jacks ? Then, no mistakes with plugging in the wrong appliance.

mikesoniat (author)  captainchaoss4 months ago

Thanks, Captain! Yes, that should work fine. In fact, that was my original plan. I later decided to go with the 110 outlets so I wouldn't have to hack my lamps.