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aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

12V LED lights

Yesterday I just had a long power outage in the evening/night, so I wonder if anyone ever tried to use 12V LED light bulbs for illumination.

I happen to have a 12V battery in the kitchen hooked up to a float charger, so with an efficient bulb or two, I can have quite a bit of light. I just searched and saw a few 12V light bulbs, many for automotive use, and I wonder if there is a way to know if they use a resistor, or some low loss electronics to regulate the current.

TIA

dennismurphy
Put me on hold? I'll put YOU on hold
Premium Member
join:2002-11-19
Parsippany, NJ

dennismurphy

Premium Member

said by aurgathor:

Yesterday I just had a long power outage in the evening/night, so I wonder if anyone ever tried to use 12V LED light bulbs for illumination.

I happen to have a 12V battery in the kitchen hooked up to a float charger, so with an efficient bulb or two, I can have quite a bit of light. I just searched and saw a few 12V light bulbs, many for automotive use, and I wonder if there is a way to know if they use a resistor, or some low loss electronics to regulate the current.

TIA

I found it much easier to use a 12v -> 120v inverter and a lamp with some CFL or LED bulbs.

I have an automotive jump station (an older model of this and used it with the inverter during Hurricane Sandy in the periods between generator runs. (I was cycling about 8 on / 8 off or so.). It would recharge during the 'on' cycle so I always had at least some lights. Had no problem getting 7-8 hours of 3x CFL lights + a MiFi + cell phone charger.

Long 8 days, but we were relatively comfortable, at least compared to others.

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

said by dennismurphy:

I found it much easier to use a 12v -> 120v inverter and a lamp with some CFL or LED bulbs.

Easier? Probably.
More efficient? Probably not.

Jack_in_VA
Premium Member
join:2007-11-26
North, VA

Jack_in_VA to dennismurphy

Premium Member

to dennismurphy
8 days? We had 18 days after Isabel in 2003 and 11 days after Irene. The Honda Generator was a Godsend even if it did cost a fortune to run.

Your Inverter/CFL set up sounds very interesting for the time the generator is off at night from about 11pm to 7am in the morning.

dennismurphy
Put me on hold? I'll put YOU on hold
Premium Member
join:2002-11-19
Parsippany, NJ

1 edit

dennismurphy

Premium Member

Click for full size
Coleman generator under High Tech Rain Shelter :)
said by Jack_in_VA:

8 days? We had 18 days after Isabel in 2003 and 11 days after Irene. The Honda Generator was a Godsend even if it did cost a fortune to run.

Your Inverter/CFL set up sounds very interesting for the time the generator is off at night from about 11pm to 7am in the morning.

My Coleman generator is loud, obnoxious and did I mention loud? - but I wouldn't trade it for all the tea in China. It worked beautifully every time we've needed it.

I'm not normally a fan of CFLs, but in this case, they were perfect. I have a small inverter - 150w if I recall - but it's all I needed to run 3 lamps. It's not a primary power source but gave us reading lights and such while the generator was off.

Something like this.

I'm sure stringing 12v lights would've been more efficient but the battery + inverter setup was fine for us and got us through the down time. Not to mention, it's a lot easier to
throw the inverter in my go-box I keep with the generator than to worry about finding 12v lights.

mackey
Premium Member
join:2007-08-20

mackey to aurgathor

Premium Member

to aurgathor
Really you just need 3 LEDs in series plus a resistor. Repeat until you get the light output you want. Multiples of 3 LEDs is best for a 12v source (assuming white LEDs). 1-2 is doable but will draw the same amount of power as 3 and just burn the excess off as heat. You can also get pre-made panels and strips ready to go with as many or as few LEDs as you want. We use the strips at work to replace 24" fluorescent tubes in some stuff and it works great.

Anyway, yes, if it says it's 12v then it already has the resistors built in.

/M

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

I know I can buy LEDs and I can even string them together, but that's not what I want to do for several reasons, one of them being that high power, high efficiency LEDs are usually SM, and they require a heatsink. I want something pre-made that I can just connect to either an automotive or to some other connector/socket.

My question about resistors is whether they use resistors to limit current (lower efficiency) or an electronic regulator (higher efficiency) to limit current.
Zach
Premium Member
join:2006-11-26
Llano, CA

Zach to aurgathor

Premium Member

to aurgathor
I've got a couple of 12V LED strips that were originally powered with wall warts that I use on battery power. I also have a few 12V CFLs that work well too. I get 'em at Menards but Home Depot and many RV/camping/boating stores and even some truck stops have them too.

»www.menards.com/main/ele ··· 6337.htm

Another option would be a 12V LED 'puck' lights. Most of them I've seen at the big box stores are powered with 12V wall warts.
walta
join:2001-05-22
Saint Louis, MO

walta to aurgathor

Member

to aurgathor
The MR16 LED lamps are often offered in 12 volt.

I used a few like this and was pleased with the lamps.

»www.homedepot.com/p/TCP- ··· Z1z0x2e0

Walta

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor to Zach

Member

to Zach
I kinda doubt that our HDs would carry 12V CFLs, but the I'll definitely check out some nearby RV/camping/boating stores.
TheMG
Premium Member
join:2007-09-04
Canada

TheMG to aurgathor

Premium Member

to aurgathor
I've got flashlights that are bright enough I can set one down on a table aimed at the ceiling and easily light up the whole room. 8 hours on one set of 4xAA.

davidg
Good Bye My Friend
MVM
join:2002-06-15
00000

davidg to aurgathor

MVM

to aurgathor
check walmart or most any automotive parts house, they make LED drop lights that plug into a cigarette lighter/power port in a car. they are bright as hell too.

John Galt6
Forward, March
Premium Member
join:2004-09-30
Happy Camp

John Galt6 to aurgathor

Premium Member

to aurgathor
Buy $10 worth of these:

»www.amazon.com/Submersib ··· 0FN8B1HU
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to aurgathor

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to aurgathor
Click for full size
said by aurgathor:

I wonder if anyone ever tried to use 12V LED light bulbs for illumination.

Check out LED lamps for automotive usage. This one is 10W and 900 lumen.

I usually design any automotive LED module to accept very wide DC input from 10V to 60V. That way they can be used with 12V or 24V or 48V battery bank in various state of charge.

nunya
LXI 483
MVM
join:2000-12-23
O Fallon, MO
·Charter

nunya to aurgathor

MVM

to aurgathor
I'd probably just buy a battery powered LED lantern (or two). Do you have any cordless tools? I have 2 Milwaukee LED lamps. Both are M18. One is like a flashlight (2735-20), and will run all day (8 hours) on a fully charged 4.0 Ah battery.
The other is like a worklight (2361-20) and will run about 4 hours on high and about 6-7 hours on low with a fully charged 4.0 Ah battery.
I'll bet most cordless tool brands have something similar.
I have about 8 batteries and can charge them in my truck if I need to.
If it's out longer than an hour, I usually start up the generator. Starting a generator is a magical way to make commercial power come back on in a hurry.

I've also read good reviews on a Ray-O-Vac LED lantern that will run for days on alkaline batteries.

DKS
Damn Kidney Stones

join:2001-03-22
Owen Sound, ON

DKS to aurgathor

to aurgathor
12V or even 6v LED lights on a solar cell charging a motorcycle battery are common in many countries for homes off the grid. I know a guy who is training locals to sell and install them in Nicaragua and Costa Rica.

PSWired
join:2006-03-26
Annapolis, MD

PSWired to aurgathor

Member

to aurgathor
Wide variety of 12v LED lights available here:

www.superbrightleds.com

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

Lemme answer all unanswered comments in one:

[walta] Will take a look at those; unfortunately, they appear to be online only items
[TheMG] I've got some flashlights, too, but I'd much prefer some ordinary light bulbs
[davidg] Will take a look
[John Galt] nope.
[lutful] that looks pretty damn good for 10W
[nunya] I actually have a couple of lights that made specifically for my tools' batteries, but they use small, lame, incandescent bulbs
[DKS] will look for them
[PSWIired] Looking at them right now

John Galt6
Forward, March
Premium Member
join:2004-09-30
Happy Camp

John Galt6

Premium Member

Click for full size
You're talking to a guy that were through ~20 power outages in the last 5 days. The 70-80 MPH winds tore stuff here...

I use these:

»www.brinkmann.net/produc ··· 9-3042-1

"White L.E.D. lights last continuously for 7 days"

cowboyro
Premium Member
join:2000-10-11
CT

cowboyro to aurgathor

Premium Member

to aurgathor
I have a generator. Made in China. I had no issues running it for 6 days after Sandy.
It's not that loud - actually much quieter than many lower-power US-made ones.
It uses a very common engine so parts are no issue if it ever comes to that.
It holds all UPS-es without complaining.
It powers the entire house. I can start the A/C unit with it. I can run the clothes dryer with it.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to aurgathor

Premium Member

to aurgathor
said by aurgathor:

[lutful] that looks pretty damn good for 10W

Similar 10W/900lumen camping lamp but overpriced.
»www.ebay.com/itm/Portabl ··· 23319191

*** Most IKEA LED desk lamps are actually 12V which is provided by the AC adapter. They also have LED replacement bulbs for their 12V track lights and cabinet lights.

»www.ikea.com/ca/en/catal ··· m/20515/
alphageek911
join:2007-08-10
Fresno, CA

alphageek911 to aurgathor

Member

to aurgathor
said by aurgathor:

My question about resistors is whether they use resistors to limit current (lower efficiency) or an electronic regulator (higher efficiency) to limit current.

Most 12V LED assemblies (and 120VAC LED devices), use a DC-DC switching converter, not resistors. They are reasonably efficient, often in the 90% range. Here's one example of a driver IC- »www.linear.com/product/LTC3454

aurgathor
join:2002-12-01
Lynnwood, WA

aurgathor

Member

I do know that with 120 VAC devices, unless they use something like 30+ LEDs in series, they must use an electronic regulator or be horribly inefficient; however, with 12 VDC, they could use 3 - 4 LEDs in series and a small resistor.
Expand your moderator at work

mk4111
@start.ca

mk4111 to aurgathor

Anon

to aurgathor

Re: 12V LED lights

Look on ebay for 5050 SMD Panel, i use a bunch of those with a variety of battery combinations.
alphageek911
join:2007-08-10
Fresno, CA

alphageek911 to aurgathor

Member

to aurgathor
said by aurgathor:

With 12 VDC, they could use 3 - 4 LEDs in series and a small resistor.

They could; I've never seen that in a commercial product, though.

I have some very cheap offshore import MR16 LED lamps, and even they have switching regulators in them. I can get IC LED driver boards from China for less than 50 cents each, even in small quantities, so cost isn't really that much of an issue.

aurgathor
join:2002-12-01
Lynnwood, WA

1 edit

aurgathor

Member

Good to hear that. So I guess I can assume that unless proven otherwise, 12V LED lamps will be using switching regulators.
alphageek911
join:2007-08-10
Fresno, CA

alphageek911

Member

said by aurgathor:

Good to hear that. So I guess I can assume that unless proven otherwise, 12V LED lamps will be using switching regulators.

All I've come across have, at least. Another choice if you need brighter lights could be automotive HID lights, they are nearly as efficient as LED, and are available in higher wattage configuration (35 and 55 Watt are common), at a reasonable cost.

rfhar
The World Sport, Played In Every Country
Premium Member
join:2001-03-26
Buicktown,Mi

rfhar to aurgathor

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to aurgathor
We bought a camp lantern three years ago, then two years ago bought our kids all one for Christmas. They all have seen a lot of use on the original batteries and they are cheap.
lutful
... of ideas
Premium Member
join:2005-06-16
Ottawa, ON

lutful to alphageek911

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to alphageek911
Click for full size
said by alphageek911:

said by aurgathor:

So I guess I can assume that unless proven otherwise, 12V LED lamps will be using switching regulators.

All I've come across have, at least.

Yes.

Modern 12V LED lamp assemblies accept "nominal" 12V which varies based on battery status in a car or AC voltage in a home. A tiny driver board is hidden inside the base of larger lamps. Above is an MR16 lamp.

Very small automotive lamps often use a single LED and a surface mount driver IC on same board.