12v LED lighting for cabin

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
We have a cabin that is off the grid and has no electrical service. We currently run everything (fridge, stove, lights) off propane, but propane lamps aren't all that bright and when several are lit in the summertime, they add to the heat in the cabin.

I am thinking about starting to install some 12v LED lights on a trial basis to supplement or replace the propane lanterns. I've found a number of RV fixtures that seem like they'd do the trick (they seem to be designed to handle voltages that aren't perfectly stable), but other than a few light fixtures I haven't picked up any supplies. Initially, I plan to install about six lights: three "reading lights" that put out 190 lumens each and draw 3.12 watts per lamp, and three 'dome' lights that draw 6.8 watts per fixture and put out 410 lumens each. If we like how these work, we'd likely add a number of additional fixtures in the future.

I do have a single group 27 deep cycle battery that I'm planning to use (at least initially), but that's it. Eventually, I hope to add a solar cell and controller to charge the battery (or batteries) all the time, but for now I'll be recharging the battery manually as needed.

I'm not entirely sure how to figure out how long I can expect to run these lights off the battery before it will need to be recharged, and I'm not sure what size wire is needed between the battery and lights (most likely, the battery will be about 30' from the lights). Although we'd never have all the lights on at the same time, we'd probably run lights the equivalent of 2-3 hours a night.

Any ideas of what sort of wiring I should be using and how much battery life I can expect? Any websites you know of that have good instructions for setting up this sort of thing (especially when it comes time to add the solar power part)?

Thanks,
Jim
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Harbor Freight has low cost LED solar lights that work fairly well for the price, $19.95 and $29.95 on sale, which is about every other week.

​I put one of the cheaper ones on my wife's shop (she calls it a studio) a couple of years ago and it works well. They have everything as one unit and have motion sensors, they also have solar shed lights. About the only thing you would need to do put a switch inline so you could turn it off and on when you wanted too.
 

muskyfins

Chief Petty Officer
Joined
Jun 7, 2012
Messages
578
Based on experience. I installed some LED strip lights in the boat this year. Per the manufacturer, I should be drawing 50 watts. I have run them for hours on end from a deep cycle house battery (can't remember the size) and run the radio and fridge at the same time. Never dimmed even a little. If I were just running my lights, I'm thinking I could get several days of night time only use on a single charge. They are obnoxiously bright and would make excellent ambient lighting. Actually I use them instead of my courtesy lights now.

Based on calculations (which I might have wrong since I hate electrical), I believe you will be drawing 5 amps. So a 105 AH battery, should power your lights roughly 21 hours.

Somebody correct me if I did that wrong....but that's how I would calulate it.
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
I have converted both of my RV's to Warm LED lighting and have loved them, in my 5th wheel a couple of years ago, I went inside to make sure going ok and no problems during the wintertime storage period, That was in later part of April, I thought I had turned all of the lights off, but low and behold when I went to take it out of storage in early June, there was one LED light still burning bright, I had left it on, the rig was not plugged in, so it ran for over a month and a week without drawing the battery completely down. At that time, I had one group 24 deep cycle on the rig.

So they don't kill batteries very easy.

In your situation, I would pick up one of the 3 panel solar systems that Harbor Freight has on sale all the time and pick up a charge controller from them, set it up where it would receive the most solar exposure and go have fun. The solar set up would maintain the battery and keep it up, so you have the power for lighting at night.

We went to all LED in our house and it dropped my power bill a little over $20 per month and I have not had to replace one yet, did that 3 years ago when Home Depot had them on sale on the 4th of July special.
 

fishrdan

Admiral
Joined
Jan 25, 2008
Messages
6,989
You'll be able to run those LED lights for a long time, just have to add up the power draw and battery capacity. 12W @ 12V = 1 amp, so 105AH battery would run a 12W light for around 105 hours, 24W for about 50 hours, ect..

Not entirely on subject, but anywho... I run a 300W LED fishing light off 2- Group 29 batteries, and it will 8 hours or so... (Don't look at the light or you'll go blind! Probably not something for the cabin :D)
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,454
So you don't kill your battery capacity, only discharge it 50% which is slightly under 12.0V.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
OK...

Total wattage - (3 lights at 3.12 and 3 at 6.8) is 30 watts. At 12 volts, that's 2.5 amps.

So, let's do the calculations. First off we need to decide what an acceptable level of voltage drop in the wires will be. Let's say 2 volts.

We'll use this chart for resistance values.
wire.GIF


Total current will be 2.5A. We'll tolerate 2 volts drop. R=V/I. So R=2/2.5=0.8Ω. You have 30 feet there and 30 feet back. Total 60 feet. 0.8/60ft=0.01333Ω/foot (or less). That's 21 gauge or thicker... Personally, I'd use 18, or even 16 gauge, just for the physical strength.

How long will the battery last? 2.5A, 105A-hr battery. To take it down to 50% (52.2A-hr) at 2.5A will take 52.2/2.5= 21 hours.

HTH,

Chris.........
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
It all depends on how much light you want and the actual type of light. DO you want warm white, cool white or anything else? Do you want lots of light or merely some to get around? Once you determine what you want, then look for such LED fixtures you satisfy those requirements. And like previously stated, just add up the current draw or wattage, if they offer that info, and determine how long you can run them from your battery setup. But don't pus your battery to the limit. As your battery gets older, it's capacity drops as well. Another thing you can look for is the lumens each light outputs to see how much light you will get for the current draw. You can compare LED lumens to incandescent lumens to see what each LED can offer. JMHO
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
Thanks, everyone, that is very helpful.

achris I had come up with 2.5A using an online calculator, too, but the charts with resistance values make my head swim, so I wasn't sure about wire guage. After doing some reading elsewhere, I decided to go with 16AWG wire just to be safe. Sounds like I guessed correctly! Also After doing a bit more reading, I've decided to bite the bullet and get a solar panel, charger controller and fuse block and do this right.

gm280 , I confess I forgot to check out the warmth of the first fixtures I bought. I prefer the warmer light from typical incandescents, so subsequent purchases will be done with that in mind. We have enough places where a light - any light - would be welcome that I can repurpose these first fixtures if they are too harsh.

I found a kit on Amazon that includes the panel and charger (https://www.renogy.com/renogy-100w-12v/starter-kit/) and I've ordered some inline fuse holders for the main power lines (supposed to use 30A between panel and controller; same between controller and battery). I also picked up a small fuse block to use as a distribution panel.

This should be a fun little project, and if it saves me having to haul a few 60# propane cylinders across the lake, I'll be happy! (I also won't mind saving the $$ to have those tanks filled. Propane in Canada is expensive!) We'll still run the stove and fridge off propane, but the propane lanterns will be more of a backup for the LEDs.

Thanks, I'll let you know how it turns out!
 
Last edited:

82rude

Rear Admiral
Joined
May 8, 2012
Messages
4,082
Most likely your not looking for this but i will tell you about my experience.Used a cabin for a week that ran all units on propane (fridge stove lights).I also did not like the lights,so i found 6 inch diameter lights at my local ctc that had about 20 leds around the outer perimeter.They took 3 aaa batteries .I bought a 1/2 dozen and scattered them around the cabin . They lit up the large cabin very well for a week and i still use them the odd time on the same original batteries.Im getting a couple for the inside of my ss160 also_On a side note every light in my house is led and i like them a lot.
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
I'm not familiar with ctc, 82rude... are you referring to Canadian Tire, or someting else? (You're near the Soo, aren't you? That's not far from our place.)
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
I am sure you all know that if you find a nice looking light to but in your boat, you can replace whatever type bulb it comes with with an LED version really easily. So if you find a fixture you really like, buy it and swap the bulbs. JMHO
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
I am sure you all know that if you find a nice looking light to but in your boat, you can replace whatever type bulb it comes with with an LED version really easily. So if you find a fixture you really like, buy it and swap the bulbs. JMHO

The 12v fixtures I've seen don't seem to have replaceable lamps... I know if you're using 110v fixtures, you just buy a different lamp, but these 12v LED fixtures seem to have lamps that are integral to the fixture. Maybe because they lamps are rated for 100,000 hours or such?
 

82rude

Rear Admiral
Joined
May 8, 2012
Messages
4,082
Yes canadian tire corp.Are you on a lake east of me?I seem to remember something from before.Lakes are really full this year what with the monsoons.
 

MTboatguy

Fleet Admiral
Joined
Jul 8, 2010
Messages
8,988
Almost all of the RV interior light fixtures have replaceable bulbs in them. Do a search on ebay for RV interior lights and you will see the various types of fixtures that are available that would work in your cabin, some of this RV's now a days are bigger than vacation cabins!
 

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Almost all of the RV interior light fixtures have replaceable bulbs in them. Do a search on ebay for RV interior lights and you will see the various types of fixtures that are available that would work in your cabin, some of this RV's now a days are bigger than vacation cabins!

​Yes, I just google search the number off the incandescent bulb and include LED, I haven't had much of a problem replacing every 12V bulb I've needed.
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
Yes canadian tire corp.Are you on a lake east of me?I seem to remember something from before.Lakes are really full this year what with the monsoons.

Yes, Patten Lake. About 35 km north of Bruce Mines. I was up there in early June and couldn't believe how full the lake was.
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
Almost all of the RV interior light fixtures have replaceable bulbs in them. Do a search on ebay for RV interior lights and you will see the various types of fixtures that are available that would work in your cabin, some of this RV's now a days are bigger than vacation cabins!

The first few that I've ordered were RV fixtures from Amazon, but I'll check out EvilBay, too!
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
​Yes, I just google search the number off the incandescent bulb and include LED, I haven't had much of a problem replacing every 12V bulb I've needed.

Cool, I'll have to check them out. The first one came yesterday, and they are sort of like a dome light, but the LED panel is built right into the fixture. My little spotlight/reading lights haven't arrived yet.
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
A follow up question: I have a large deep cycle battery (group 27) that I was going to use initially. I also have a standard starting battery (flooded cell, group 24) battery. Can I wire the two in parallel or do I need to have similar size/type batteries?
 
Top