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Small Cabin Forum / General Forum / 12v led lighting
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Aklogcabin
Member
# Posted: 19 Jan 2022 12:44
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I was wondering what would take to put a 12vv led powered light system in our cabin. For the last 5 years ago so I have used the same 12v car battery for things and trying to upgrade.
Probably 2-4 lights upstairs. 5-6 scattered around in the lower level. Hopefully not all used at the same time.
I'm thinking of wiring it like you would a house. With lights going through a switch to lights in the ceiling. Or to a lamp.
Using telephone wire. I could run several circuits through the same casing. Using different colors for different circuits with a common ground.
Probably should upgrade the battery to. I know a fellow who works on golf carts n might be able to score a used battery or 2 from him. Would these work ?
I have a 120v battery charger now powered off a generator to charge batteries. But just bought a 2500w duel fuel champion generator. With the little ports on them. What would be the best way for charging batteries ? Off a portable battery charger or off the generator ? How many can I run ?
Or maybe I'm all wrong. My goal is to have 12v lights. Throughout the cabin. Powered off batteries in the generator shed by the generators.
Thanks all
Upstairs
Upstairs
Great room
Great room
Kitchen area
Kitchen area
Cabin n generator shed
Cabin n generator shed


FishHog
Member
# Posted: 19 Jan 2022 12:53
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Just be careful that you don't make it look like 110v wiring that someone mistakenly hooks up to.

I ran just like a normal house setup with switches in the wall to 12v LED lights. You can get 12v LED edison bulbs and use normal household fixtures.

Hooked up to my 12v solar system batteries. I also put a lot of pull chain light fixtures so that its easy to turn individual lights on and off. A main switch turns 3 on, but then when I don't need all 3, I can pull cord one or two of them off.

They are 13watt bulbs but normal 100w equivalent. I think they are an awesome addition.

Its no big deal if someone screws a 110v bulb in accidently, but it can be if someone hooks 110 into your 12v system, so make sure that won't happen.

travellerw
Member
# Posted: 19 Jan 2022 13:28 - Edited by: travellerw
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FishHog has the right answer.. Wire it like a 120V system to prevent accidents and future proof.

However, at that point it may make sense to just run 120V LED lighting through an inverter. After you factor loses of the 12V through the wires VS losses in the inverter, its pretty much a wash. Except that the 120V LED lights can be bought anywhere for super cheap now! Plus you can run other 120V things (like a coffee grinder). Then get an auto switch (about $100 on Amazon) so when the generator is started it automatically powers up the plugs and lights, then switches back to inverter when turned off.

As to the generator.. DO NOT use the battery charging port on it. Those are basically for emergency use only as they have zero circuity (just a bridge rectifier that puts out 13.4V). Use a good smart charger with an equalization phase.

gcrank1
Member
# Posted: 19 Jan 2022 14:05 - Edited by: gcrank1
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The genny 12v power taps dont put out enough amps to recharge big capacity bat-banks, use As Much Charger off the ac outlet As Your Bat Chemisty C-Rate can take (and that is within the gen's capacity).
Fla is pretty safe at C-8; ie, 12v 100ah/8 = 12.5amps, a 200ah could take 25amps, etc. But check/verify with the bat manufacturer.
Lfp can do sooo much better, a 100ah can easily take 50amps!
I tried straight 12vdc, combo 12vdc and 120vac and settled on total 120vac. No regrets in over a year now.
And most of last year was powered with 2 old bats, iffy ah's but call it 100ah at best. A new grp 27 100ish ah 'marine deep cycle' would work fine, 2 even better (never a basic 'car bat' unless desperate).
Fixtures are common, inexpensive Edison bulb type with pull chains (no extra switches to buy or install). Our bulbs are Edison looking, 9w/60ish w equiv LED (led, the ONLY way to go). We have 4 fixtures strategically placed but rarely use more than 1. They are sooo efficient that I dont even have to calc them any more! Because they draw so little the wiring does not have to be big, I used common, cheap, easy to work with lampcord.
I use a small pure sine wave (psw, dont get anything else!) 300w inverter, low .5a draw. Even if I leave it turned on all night after we turn everything off I cant see a diff on my dig-vom of the battery. I turn it off just to hopefully extend the life of the unit. And I turn it off during times we arent running anything, thats why it has a switch. BUT, if I were buying today I think Id get it in a 500w size, the amps it would use are so marginal over the 300 that it wouldnt matter and someday the 'extra' capacity might be nice. A small inverter with capacity closer to your load is far more efficient than a way oversized one to run 1 or 2 led bulbs most of the time.
It powers the led lights, a usb port is in it, can charge tool packs, box fans, etc., all the light-duty stuff.
Any big draw stuff is run off the little 1700/2000 inv/gen (big tools, microwave, etc.). Until I was satisfied with my solar array I also had the ac charger hooked up so whenever the gen ran it was charging the bank.
I have the solar, bats and gen at the toolshed/powerhouse 90' away and one 120 line to cabin. I am the transfer switch; start the gen, unplug from the inverter, plug into the gen. The big draw stuff is on its own outlet in-cabin (seperate from the lights) for only when gen runs. If we need the lights I plug them into that outlet. Easy swaps. This way nobody trys to run the MW off the little inverter.
Btw, with a basic battery and small inverter you can easily trial your led light fixture locations by using cheap household extention cords and lamps, probably stuff you have at home now.

NorthRick
Member
# Posted: 19 Jan 2022 15:53
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I'd go 120v AC using an inverter. 120v stuff is cheaper and easier to find. Telephone wire likely isn't thick enough. One 13 watt light at 12v is about 1 amp. 13 watts at 120v is about 0.1 amps. For wire size, it's all about amps.

FishHog
Member
# Posted: 19 Jan 2022 16:42
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I go the other way, I have a dedicated line for my inverter for the odd time I need 120. Typically just recharging my laptop.

all the other time my stuff is 12v and only drawing power when I have a light on.

The other way my inverter would be on 24hrs a day using up idle power for the odd time I need to flick a light on for a couple minutes.

My lights in total would be a couple hours a day max and usually just one 13w light.

Running an inverter 24hrs a day would consume much more power. But that all depends on your needs which are well worth calculating before making a choice on equipment.

ICC
Member
# Posted: 19 Jan 2022 17:27
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Quoting: Aklogcabin
Using telephone wire.


No.

You may have noticed in reading that wires have resistance. Long wires cause the voltage at the other end of the battery to drop depending upon how much current is being drawn, the wire gauge and the length of wire.

Most advice is to limit the voltage drop to 3% maximum. When dealing with low voltages IMO, it is even better to limit the drop to 1.5 to 2%.

Telephone wire in common use today is 24 gauge. It used to be 22 gauge. But I just looked and see that the bulk wire at Home Depot is now 25 gauge, a touch smaller than 24. (As numbers get bigger the wire size gets smaller, FYI).

Humph. My g-voltage drop calc doesn't go to small enough gauges to use. So I found an online one that does. It is here. You can use it to figure different things.

I have lots of 12 VDC led lights in by bus/rv. some under cabinet lights that get used a lot have the following specs: 18" length, 12 volts, 9 watts, 800 lumens and 0.37 amps. To wire one of those up with 25 gauge phone wire and keeping the voltage drop to 2% gives me 3 meters of wire (15 feet) from battery to light.

If you want to run just some led lights start by finding lights you could use. How many lumens do you need? Compare the lighting you use in the home where you live. Would that work? Would less lumens work? Or not? Once you know the lumens needed then go looking for lights that could be used. Look at the specs to see the amps or watts needed for that light. (watts divided by volts = amps). Run the wire gauge / voltage drop calculator.

You will likely find that you would need bigger wires to run to every light location you want.

Running 14 gauge romex makes a lot of sense. BUT, IMO, you should not run any AC wires through the walls if you are running romex for DC use. It may be easy enough for you to remember what is 120 VAC and what is 12 VDC, but if you get old enough you may forget. A mistake could be deadly. I would advise going all 12 VDC or all 120 VAC, OR using wire for the 12 VDC that could not be confused with AC. But not telephone wire.

Doing it as FishHog did can be a good compromise for a cabin IF one's 120 VAC needs or wants are very limited.

DartNorth
Member
# Posted: 26 Jan 2022 20:46
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Wire it up for 110V. Wire it as you would if you were on grid, to code (or as close as possible). Use a low ghost draw 110v inverter. We use a 300W go power pure sine inverter. It's about 7 amps draw per 24 hours. The led bulbs in our lights are all 8-12 watts. We have outlets to plug in small appliances. Can switch over to generator for larger appliances, tools, etc.

Better yet, get an auto transfer switch to make switching from inverter to generator even more convenient. We went with GoPower again for that and got the TS-30. It powers from the inverter until the generator is started, then switches over automatically. So quickly, it doesn't affect electronics.

For charging, get a proper 4/5 stage charger. Size it based on your battery bank. If you have an auto charger already, that will work as well, and is usually faster/higher amperage than what comes out of the generator. Plus, some generators will only output either 12v or the 110V, and not both. With a separate charger, can charge while running other 110v stuff.

gcrank1
Member
# Posted: 26 Jan 2022 21:04
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Have you seen the 'Edison looking' led solar bulbs? I bought the 3-pack off Amazon (about $30), came with a small solar panel and long wiring that is a mini-usb into each bulb. Each also has a small push switch and hanging hook. They will also charge off a wall-wart.
I keep them in reserve for back-up or a portable to take and hang/hold where I have no lights .
If I had just a simple camp or cabin Id probably just use them instead of putting in a whole system and wiring. Too Easy!

Brettny
Member
# Posted: 27 Jan 2022 04:37
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I wouldnt mess with a separate 12v light system now a days. As for the standby losses of a inverter..if you cant get by 1 or 2 days with just the inverter losses your system is to small. If your trying to keep more power in your battery just add another solar pannel. Pannels are prety cheap now and even cheaper used.

If your car battery is 5yrs old I would say it's far outlived its life as a solar battery. First thing I would do is upgrade that.

FishHog
Member
# Posted: 27 Jan 2022 07:14
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Quoting: Brettny
if you cant get by 1 or 2 days with just the inverter losses your system is to small


Unless you live further north and get way less sun in the shoulder seasons. I went 10 days with no sunshine this fall. Solar was putting out about 1amp at best.

I was in full energy conservation mode, but made it through.

Point is everyone is different with their need and location, so plan properly for your needs.

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