Help with cabin lighting ?

[Rick004]

Hi ! This looks like an excellent site !! I'm building a small off grid cabin (16x20) . I will have propane appliances  and a woodstove for heat , I was wondering what would be the most economical and efficient lighting system to run on solar and what size of panel would I need for about 6-8 lights ? Thanks !!

[Frank S]

Before trying to decide on what size panel and amount of batteries to buy . you might want to jot down your total energy requirements will you require any electricity other than simple lighting how about radio TV or computer will the cabin be used frequently or only occasionally
 For lighting the way the prices of LED has come down a person would be hard pressed not to consider them

[Rick004]

Thanks for replying !! Basically it would be just the 6-8 lights and maybe a laptop at the most !

[birdhouse]

for the minimal use you're talking about, i'd go with a 12v system.  12v leds can be had through china (fleabay) for under $2 a module, shipped!  if you're willing to use a car charger for the laptop, then no inverter is needed for your system, assuming you won't be able to run anything off a standard 120v plug. 

everything will be direct 12VDC. 

if this is all you really ever plan on powering with the system, i'd go with a pair of trojan t-105RE 6v batts wired in series for 12v, and a 100w panel.  add in a charge controller(i'd reccomend a morningstar "prostar" or "sunsaver") and you're off to the races. 

adam

[dnix71]

My apartment is 14' x 15'. I have a single 2-watt led cluster lighting the room. 6 or 8 of those would be bright enough to conduct surgery under. I bought the one listed below in September, 2011. It still works fine. I soldered wires to the pins to make a custom socket.

http://www.ebay.com/itm/G4-18-LED-180-Lumen-Cool-White-12V-AC-DC-2-Watt-Bulb-/150647480705?pt=US_Wall_Fixtures&hash=item23134a2181

[Rick004]

That's what I'm looking for , thank you Birdhouse ! I would like to keep it strictly on 12 volts . I'm not familiar with led lighting the ones your talking about are they just the little bulbs and you build the fixture or is it a complete light fixture ?  The reason I wanted so many lights was for the bathroom , loft , kitchen area, front and back porch , and living/dining area .

[globalworrying]

I have a cabin just like you are talking about, for about 5 years now. if it is just for occasional use I would
reccomend sla agm batteries (sealed) they cost more but do not need watering, equalizing, etc.
I have 3 group 27 100ah batteries, one 85 watt panel and a 2000 watt inverter, mostly the inverter is
used for watching movies and making popcorn with the smallest microwave we could find, but it is nice to
be able to run a vacuum for cleaning up. since we are usually there for just the weekend it works for us
I have propane lights and fridge. I am in the sign business so I have some led lights as well, the ones I
have are in a string with double sided tape on them so all you have to do is figure out a way to switch them.
before leds became cheap I got some old fluorescent lanterns, the kind that took 2 lantern batteries,
eliminated the batteries and direct wired them into the system they still work great. if you are in a big city call around to some sign shops an see if they will sell or give you some of their remnant leds.
if not let me know how to get ahold of you and I can mail you some.

[birdhouse]

honestly, i disagree with the sealed (SLA) batteries.  if the charge controller is set just a bit too high, it'll boil them dry, or if they get out of balance, there isn't really much equalizing that can be performed. 

i think there's a reason most all offgrid setups use flooded lead acid.  you can beat them up, drain them too low, and then just boil the snot out of them to bring them back.  if you visit your place once in the spring, once in fall, and once in the summer, that's plenty of times to check/add water.  with a properly designed system, you should only have to water them 2-3 times a year MAX. 

i personally like FLA batteries much better as they seem harder to kill, and easier to resurrect if you've almost killed them.  make sure to set the equalize to manual, so your controller isn't boiling them once a month while you aren't there for months on end. 

my offgrid place is unoccupied for months at a time during the heart of the winter, and the heart of the summer.  i check water levels everytime i'm there, and equalize 3-5 times a year.  i only add water 1-2 times a year to my FLA bank and have never had an issue. 

but this is all my opinion.

adam

[OperaHouse]

I recommend strip LED lighting. You can get 5M of 3528 for $10.  Larger 5050 are more.  Cut to any length you want and stick them under kitchen cabinets etc,  Wrao around an aluminum tube like an old chime or umbrella post and get 360 degree light.

[Rick004]

Thanks to everyone for their great ideas !! I was also wondering about what size of wiring is best , should I use regular house wiring or smaller gauge automotive wiring ? The cabin is in a remote area but we will be there every weekend from spring to fall and maybe 3or 4 times for ice fishing in winter . Which is another question how do I store batteries if the area we live can get as warm as (+30c) in summer and (-28c) in winter very cold !!

[bart]

   As far as remote cabins, low temps, and batteries. There is a current discussion going on right now about this. Read more than just this thread.
   if you don't own a meter, don't know about ampacities of conductors and don't know ohms law, then be safe, get an Electrician Please.

[Tritium]

Some of the easiest to use 12V led lighting available:

http://www.hobbypartz.com/79p-10216.html

The strips can be cut down as small as groups of 3 then just solder on the leads and go. Adhesive backing, many colors available also.

Thurmond

[Rick004]

Thanks for the advise Bart ! I'm not building till late spring that's why I'm trying to research as much as possible !

[birdhouse]

voltage drop with 12v is terrible.  go to an online voltage drop calculator to get an idea.  even with led, i'd still run #12/2 romex or MC for everything. sure 14/2 would probably be fine, but the cost is very little difference, and if you all a sudden decide to switch bulbs, or piggy back a bunk of leds on one wire run, then you'll still be OK.  not to mention the 12v outlets.  if you run a few 12v automotive type (cigarette) outlets, who know what may be plugged into them.  IE: air pump for mattresses ect...  those may only draw 100-200 watts, but 100-200 watts at 12v is ~8-16amps.  getting close to the 20A rating of #12 wire. 

as far as temps, batteries pretty much wont freeze IF THEY'RE FULL.  i think it takes in excess of -40F to freeze a full battery.  you have to be careful drawing the bank down too much if it's really cold out.  the lower the SOC of the battery, the higher the potential freezing point is.  the good news is, anytime power is being pulled out or pushed into/out of the battery bank, heat is created.   might want to store them in the cabin in a steel enclosure that is vented through the roof or higher on a wall.  battery vapors under heavy charge are very explosive and corrosive.  better yet, would be to build a small attached bump out in one of the cabin walls.  this would give them some heat while there, yet give a bit of separation as well. 

i keep my batteries in an unheated shed, and they've been just fine (though reduced capacity) even while using the system at -5F. 

adam

[ghurd]

voltage drop with 12v is terrible.  go to an online voltage drop calculator to get an idea.  even with led,

I do not totally agree.
Mostly because of the LED draw required to 'hit the target' toilet at 3AM in a cabin, which could be 1ma at 12V.

No reason to get blinded by light using the same power to pee as too see to cook?
No reason to have all 8 lights on at the same time either.

I would still run #12/2.
G-