LED Lamp Notes 5" 12vdc Strip As As Sold On eBay

[MEXICOWANDERER]

2x Super Bright White 5.5" Car COB LED Light DRL Fog Driving Lamp Waterproof 12V

http://www.ebay.com/itm/301747417395?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

• COB plate construction ear-crimped onto aluminum backing
• 25 gauge power wires soldered to pin-head solder points
• Units have zero sealing. Face of emitter is plastic
• With power supply at 12.00vdc aluminum substrate achieved 148 degrees F in three minutes.
• Delta T temp of 78 F
• Six minute test failed one strip
• 12.00vdc required 713ma which of course rises as temperature rises
• Requirement of additional heat sinking is mandatory
• Raising voltage to 13.2 achieved 140F temp of aluminum substrate in under 120 seconds

Personal Opinion: Power wires are extremely difficult to work with unless soldering is employed.
There is zero power wire strain relief. Exampled perfectly when one strip arrived with neg wire already broken off at solder point. Solder point is pin-head size. Epoxy encapsulation is strongly recommended.
I used JB Weld to encapsulate wire connections and as an adhesive to bond strip to appropriate aluminum heatsink. Thermal conductive compound was used to thermally bond strip to added heatsink.

If treated as an incomplete emitter component, these strips are extremely bright at 12.5 - 13.6 volts. Their lack of mounting tabs makes their utility challenging.

The useful thermal threshold seems to occur at 11.7 volts in which temperature seems to limit at 33 degrees Delta T. Lumen output at this potential is objectionably limited.

[MEXICOWANDERER]

Keep in mind I referenced 12.00 volts as a baseline. Temps accelerate exponentially splitting away from lumens increase around (roughly) 12.5 volts. These parts arrive with double-sided foam sticky tape. A decent quality LED operated at <50c 122F will last a staggering amount of runtime.

Today I received an answer from a vendor that was hilarious. As usual, the LED product was denoted by lumens and watts. Apparent, not actual watts. I constructed a question limited to 2nd grade grammar. How many milliamps at 12 volts?

The answer arrived "What is a milliamp?" I even supplied examples (.5 .7 .9)

[ctpres]

Pretty sure I have same ones tested. I used TWO to replace tube lights in kitchen. Day one - DW wow that's is great. By week three most of one out and worthless. Supplied double stick failed on both due to heat and they fell on lens. When second one fails will try something else. Can not recommend use in enclosed space or with typical RV DC voltage.

[landyacht318]

Mex's observations indicate these are not a good choice as they get too hot. They were designed as daytime running lights and would likely see adequate airflow to keep them cool in such usage, but retasked as interior lighting could be a waste of money and time to wire them up.

The ones I have appear identical to those he linked, but who knows how they match up. I've not tested mine for temperature, but they have not failed.

When my back doors are closed there is no Airflow to them, and they shine into the door 5mm away. the velcro keeps the metal backing from allowing the door frame to act as a heatsink. When back door is closed but side door is opened, and I have headlight knob not rotated all the way CW, the lights are illuminated.

I would guess mine have several dozen accumulated hours over the last year where they were lit with no ventilation and they still work.

it appears the ones Mex has tested are likely brighter, driven harder and hotter and would not survive in the location I use mine.

So buyer beware. You do not know what you buy will actually work in the intended usage, for long

[DarthMuffin]

So those look useful. Got any suggestions for similar products that aren't junk, have mounting tabs, etc?

[landyacht318]

I employed such LEDs in my rear doors about a year ago.

When the doors are opened 90 degrees they fire into the back, and are thin enough that they fit in the gap with the doors closed.

I hold them in place with velcro. Used Amazing goop to reinfore the wires as there is as noted, no strain relief.

Very bright, bluish tint. Functional. I forget the amp draw but it is not insignificant.

Have not used any more heatsinking on them.

[GordonThree]

I've gotten too picky with my LEDs tastes... I don't buy anything with a CRI less than 80 now. I put a new light bar on the front of my Ram, and it is bright, but the CRI is so low, there's very little contrast from anything being illuminated. It's essentially a blue floodlight with a little yellow thrown in, or I can switch it to pure yellow, which is nice. The seller, M4 Product, claims it was built using CREE leds. Maybe Cree is lending their name to inferior emitters these days.

Also swapped out several Amazon generic interior LEDs for ones I built myself using 90 CRI emitters. The difference is staggering, like switching from a heavy overcast gray day to a nice sunlit one.

[MEXICOWANDERER]

Data speaks for itself. The vulnerability of LED even silicon carbide type should always be figured. A single new 10 watt ("12-volt") CREE chip running at max spec milliamps overheated a spiral 10-watt rated LED heat-sink*. Solution here is a fan or larger heat sink.

All new LED auto headlamp modules include a larger heatsink AND a fan. An internal fan. I have not come across an ad that happens to mention this "little" fact...

* 148 F

[TakingThe5th]

Dang! Item is out of stock.

[MrWizard]

Translation:
"dont waste your money"
unless you plan on a DIY mod with heat sinks and better wiring to make these useful