12v led light opinions

We have a number of G4 LED's in our teardrop trailer and so far we have had no failures. However I wanted a couple for spares so found a 10 for $10 including shipping from China. Since I had them I decided to see what kind of abuse they would take. During bulk charge they would be getting 14.8V. I hooked up 2 12V batteries in series with a digital read out PWM to gradually increase voltage.
To make a log process short I gradually too the array up in voltage leaving it for an hour. It was not till I got as high as I could go at 23.5 volts that a couple of SMD's unsoldered themselves and fell off, the rest still work. 

Lowes, home depo and auto parts stores have a selection of 12 volt LEDs.

I bought about 10 LED bulbs, E 27/26 screw-ins 12 volts 7 watts output which is about like a 60 watt incandescent.
I currently use 5 of them outside.
No problem so far in about 1 year use, used almost daily.
.
I got them of ebay and seem to be of good quality. I wish I could buy some with 10 watts which would be more like 75-100 watt bulb.
Here is the link where I got them from.  http://www.ebay.com/itm/5-x-Super-Bright-High-Power-7W-12V-E27-Home-LED-Bulb-RV-Lights-Warm-White-E26-/281811961435?hash=item419d4d465b  

I you are looking for 12 volt  screw-in CFL bulbs, they make them. That is what I use before the LED's. But a CFL will consume twice the amps compare to those LED with the same light output.
 

For what it's worth, I've ordered some MR16 GU10 24v DC LED track lights from Independence Electric Co (Canada) back in early 2015 and was very, very pleased with their customer service and support, but the track lights didn't end up working out for me given my setup (no A/C in central Texas). 

I learned the hard way that some LEDs (MR16-3W-LED-WW-GU10-24V) are very susceptible to heat.  I had the LED track lights mounted on the ceiling in our place in a track-lighting fixture (non-enclosed) that I had available.  I installed three of the GU10 24v DC LED track bulbs and within a month or two there were two LED GU10 bulbs that were flickering.  I immediately contacted Independence Electric Co (Canada) and they stepped up to the plate and suggested some configuration changes (ex. removal of a track-light fixture metal mesh shroud that allowed air to pass through but was still a barrier to air-flow and so was removed completely), as well as sending me three replacement GU10 24v DC LED bulbs free of charge, including free shipping from Canada (I'm in Texas) immediately.  Long story short, the heat was still too much for these bulbs, even with some adjustments to the fixture.  I didn't realize when I ordered them that 95 deg. F or above ambient temperature around the bulb is too much for these bulbs to handle and I guess the heat they generate on their own is enough to fry the driver (hence the flickering).

After I learned about the ambient temperature upper limit I decided to jump ship and went to "TheLEDLight.com" and found a more heat-resistant LED light fixture that can handle 24v DC.  So far, after almost a year, they have been great and have a two year warranty!

Bottom line...Independence Electric Co (Canada) is a great company, as is TheLEDLight.com, and they both have a pretty good selection.  Yes, you pay more for the bulbs, but I'm guessing you're paying for the quality.  I don't doubt that if there was proper air flow and if the space was air conditioned that the LED bulbs would not have flickered...but I just got tired of dealing with flickering LEDs and went to some LED fixtures there were designed for higher ambient temperatures.

Hopefully this experience helps others out...I spent quite a bit of time trying to figure out how to obtain 24v DC LED lights for our off-grid place and I'm glad I learned what I learned.  I would not hesitate to buy from Independence Electric Co or from TheLEDLight.com again!

WiredCo has a nice assortment of LV LEDs, many of which have integral drivers so they can tolerate some voltage variation,
https://www.wiredco.com/LED_Lighting_Low_Voltage_s/1874.htm

All our lighting is all 24VDC led, and mostly home made. Why DC? Becasue our inverter gets switched off at night. And because the leds are 10V DC, why double convert?

I use this exact combination of parts: COB led, driver, heatsink.

http://www.ebay.com/itm/161404739591
http://www.ebay.com/itm/221225242717
http://www.ebay.com/itm/321757548210

Those drivers will run at either 12V or 24V, and are super efficient. The cob leds are nice and bright, good color and light distribution, not downlight focused.

Why make them myself? Becasue it allows you to seperate the driver from the heatsink (i put the driver in the ceiling rose fitting.) Putting the driver with its heat sensitive electrolytics right on  top of the heatsink is just plain daft.

Total cost per 10W bulb?  USD5.03

The OPs siuation is he has a low voltage system, right?

Look closer, thats a pack of 5 for USD15.90.

They make a great light, will run off anything from 11V to 35V... if you like to do things with your hands. Superior to anything you can buy under 100 bucks.

I wired the place with twin core 4mm2 for all the lighting circuits. However as these lamps only draw 0.8A, youd need to do the voltage drop calcs to try to reuse your existing lighting circuits. In NZ lighting is generally 1.5mm2. Youd also want to label them clearly, the red and black twin core is pretty distinctive, and hard to confuse.

DC lighting is not for everyone, but seeing as LED looks to be here to stay, for new build smaller places with short runs, cabins and small houses, etc its worth looking at. We really enjoy it, the  SO is into making light fittings out of antique bottles and all sorts of stuff.

But wait... it gets better. First, i run two leds per driver (why curse the dark), its a 0.9A constant current driver, so 10V+10V =20V, leaving just 6V for the driver to deal with (and thus running the led at 9W helps to prolong life). The driver thus runs barely warm to the touch. Second to simplify my description, the 4mm2 runs are just the legs which feed off 6AWG trunk lines. Third, the longest dimension of our house is like 25ft, so total wire length is quite a bit less than 50ft.

Theres quite a bit of other DC stuff here too. Theres 8 USB ports for phones and other gadgets, a 12V DC converter for sundry items, a 19V DC converter for the laptops, and the file server. The power monitoring system runs off its own 5V DC converter. Oh and the fridge, 24V danfoss model.

larcal...no problem, my pleasure.  I've been helped by the NAWS forum many, many times and wanted to share my experience too.

In regards to your questions:

1) The 95 degree F. ambient air temperature figure is simply an estimate by me.  When working with Independence Elec. Co. (Canada) on troubleshooting the flickering LEDs, they said that 90 deg. F ambient temperature was too hot for these LEDs (I wish I had known that when I bought them or I wouldn't have bought them).  I estimated our ambient air temperature near the surface of the ceiling at about 95 deg. F because I held a thermometer up where the bulbs were mounted near the ceiling (when the bulbs were off) in the summer.  The ceiling height there where the bulbs were mounted was probably about 10 feet high.  Like I mentioned, our off-grid place (single story with a single pitch roof) is not air-conditioned and during the summer, in Texas, especially in the late afternoon, the air temperature right near the ceiling is definitely above 90 deg. F.  We designed our place to passive solar with our place oriented to the southeast to catch the prevailing summer breeze, as well as have venting windows at the high side of the single pitch roof, plus we have ceiling fans and do the whole leave the windows open at night when it's cool and then shut the house up during the day to preserve the cool(er) air.  It never gets above about 80 deg. F at normal people height, but because we have higher ceilings, the temperature near the ceiling is relatively high compared to a house with air conditioning.

2)  The reason I initially chose the MR style bulbs is that I already had a track light fixture that accepted GU10 style connections...the track light fixture I had was the Lithonia 3 track light fixture designed for AC current with 50 watt halogen bulbs (see http://www.lithonia.com/commercial/3-light+linear+fixed+mesh+back+lamp+halogen+kit.html#.VwaRthwupms ).  I simply removed the "dimmer" switch and used the existing wiring and connected it to our 24vDC circuit in our house (I have a 48vDC to 24vDC converter because there weren't too many DC appliances available that can run off of 48v DC nominal current).  So the voltage is very much stable and regulated at about 28vDC (I can set it with a small adjustment to whatever I want around 24vDC).

3)  I decided to forgo the track light approach and go with a 'flush-mount' low profile LED fixture from TheLEDlight.com.  It is good to something like 150 deg. F ambient air temperature.  Please see: http://www.theledlight.com/ledFlushMountLights.html  They sell it as a 24vDC using a supplied driver, which is separate from the LED light fixture so the driver is not getting heated by the LED lights (brilliant!).  I have been using this 7 inch flush mount low profile LED fixture from TheLEDlight.com for awhile now under the same conditions as the flickering GU10 track light LEDs that flickered and we have not had a problem...no flickering!!

Overall...the moral of the story is...it depends.  You need to consider the ambient air temperature, especially with LED lights that have the driver integrated with the bulb.   Many times the manufacturer will specify whether the LED light fixture can be enclosed or not...this has to do with the heat they create and whether or not they fry themselves up.  In my case, the ambient air temperature around the GU10 bulbs was just too high...

Hope this helps!

larcal said:

Johann said:

larcal said:

Thanks Johann-Have written the ebay guy but hasn't answered. Have you run much at high ambient temps or voltages and how high if so?

Sorry for the late response.
High temperatures exposed around here is around 100F in the summer, later in the night it will cool down more ...like 90F. My LED's are not exposed to a constant high temperature since they are currently used outside at the wood storage area and temperatures are fluctuating between mornings and evening and the seasons.
The LED will turn off at about 6 volts and I had them run at 20 volts panel voltage today, but only for about 20 minutes so i can not tell you how long they would last with that high of an voltage. Remember that those are 12 volt Led light-bulbs and higher voltages could shorten the life.

Cool. How do you get the 6v and 20v? Some kind of controller taking 120ac and converting to range of dcv?

Wonder if running these in a room at 75-80F a lot causes a short life. If that's okay you'd be good for 8 months anyway and could switch back to ballasted cfl in the deep hot summer with no AC when even at night inside rooms can be 95F but you still need light.

I was testing and trying to rescue a complete dead bad battery that was sitting around for 6-9 month.
I was trying to use my el cheapo  china made controller to charge it, but that controller did not see the battery at all since the battery was dead and since the controller did not turn on . So this cheap controller gets the operating  power from the battery and that was interesting.
So I hooked the 12 volt nominal solar panels straight to the battery and that showed 20 volt on the meter and my chinese controller came on and showed the same voltage since the chinese controller was still hooked up to the battery power. I was trying to put a load on the panels to lower the voltage, so I turned my LED lights on which I left on. With bright sun light and being cool here right now I could not drop the voltage with those 5 bulbs at all, but the bulbs did not burn up.
After about 20-30 minutes  I tuned my breaker to the solar panels off and I could see the battery voltage dropped on that dead battery. At about 8 volts my chinese controller stopped displaying anything and went dead and the light bulbs where still on, at about 6 volts the light bulbs turned off also.