I sure hope this does not place a burr under anyone's saddle, but get ready because I am going to lapse into (lecture?) mode...I purchase LED chipset plate lampsVarious wattages 2, 3, 5, 10, 20 I connect them to a precision power supply 12.00 voltsWith a 5-1/2 digit bench DMMI read I amperage drawI multiply volts times ampsAnywhere from one-fifth to one-fourth of the advertised wattageThere is no mention anywhere EVER of a caveat of "equivalent to" which would be stupid because flourescent, incandescent, or halogen?So I take the advice of Mr Wizard. I purchase 12 volt 10 watt LED chips. They need heatsinks. I connect the power supply and the light flashes as bright as 60 amperes of arc-welder light only pure white. I have the chip solidly heat-sinked to a plate of aluminum with zinc oxide compound. The light eqvt. equals around SIX 30 watt 12 volt fluorescent fixtures.I am going to couple the 10 watt chips to an LED dimmer, a PWM control with a knob. At full potential a chip demands a lot of heat sink, possibly with a 12 volt micro muffin fan.How bright is bright? Even with my poor eyesight, I feel one single chip will light a 12' X 12' room as well as a single 100 watt incandescent lamp - with a higher number Kelvin emission it is hard to compare. The beam spread is incredible - around 140 degrees.I will use the $2.95 Chinese specials, rated at 10 watts. Mounted to a flat fixture. I figure SIX of them will give me about 50% of the illumination of a single $4.95 10 watt AUTHENTIC LED chip.So thank you Mr. Wizard!I will work out the heat sink and PWM controls to suit my application.And gag whenever I see a wattage reading for a multi-LED plate.

Pictures, or it didn't happen. LOLMore info and how to set them up in a small RV "B" Class. Where to purchase links, etc. I missed Mr. Wizards post.Thanks

The magic words missing are "I recommend". This is not a "I Recommend posting" It is for educational purposes. I need heat sinks. Did you miss that thread? When I get this system viable I intend to post images.Some folks want to learn about their endeavors. Others believe the only relevant issue about a subject is "Tell me where to buy it". I love teaching and sharing. I make a poor salesman - IMHO someone who hasn't the foggiest idea of how something works, the only issue is where to buy it, or sell it. The yellow pages, ebay or Amazon is perfect for the latter.

Mexico: Good thing you have pointed out... HEATSINKS!I find the Chinese led boards regardless of wattage rarely have enough heatsink or even thermal mass. This goes for the plastic LED flexible-strip lights that are popular with RV crowd as well. LED + HEAT = short lived LEDs ... it matters not if it's one ten watt led or ten one watt leds or a hundred 100mW leds, the heat has to go somewhere! Rule of thumb from a little company named Philips ... 3 sq in. of heatsink surface area per watt of LED. This doesn't have to be all on the horizontal plane, a heatsink with vertical fins adds a lot of surface area. Second thing to consider, surface area (fins) are only good if cool(er) air can move across them.

GordonThree, thank you! That rule of thumb you quoted is going to help me. I am considering buying a copper CPU heatsink and mounting as many (6 max) chips on the CPU pad. I purchased some thermal adhesive but I do not know how it compares thermal transfer wise to old-fashioned zinc oxide past and drilling micro holes for #2 screws.I also need to conjure up somewhere a micro 12 volt to 5 volt DC to DC converter for the CPU heat sink fan. Yeesh, if I end up throttling back on watt/minutes with an LED dimmer I wonder how this is going to affect the DC to DC converter. Will it throttle back as well or end up cycling.Availability and the Oops factor inhibit full scale tinkering. Fifteen hundred mile journey to fetch packages is a bit daunting.

The ancillary objective is to construct a device unlike anything else I have yet seen. If the overall dimensions work out and a suitable lens cover for the device can be made, a single 10 watt lamp in a strategic area of an RV (with a dimmer) will allow versatile lighting. The running of wires from the controller to the lamp is going to present a challenge for some folks. But the concept will be crystal clear and understandable to everyone.

More Griping About Missing Standards LED lamps and lumens

44 Replies

MEXICOWANDERER
Explorer
Feb 25, 2014
As they say down here "Mexican Listo!". Found a cover for a Coleman roof air laying by the side of the road. Going to make a great hood. Silicone grease across the chips and connections. The fan is going to have to fare for itself.

Going to have to take a full case of Pacifico to encourage the guys with the CFE bucket truck to mount it. A total of four stainless steel band clamps for big rigs is going to clamp the light pedestal to the pole. Vertical gray electrical tubing to pass the wires and 14" cable ties (black) to clamp the pipe to the pole. Then boondockers can have light when necessary.
NinerBikes
Explorer
Feb 25, 2014
What do you plan to use as a lense over the LEDs, to protect them?
MEXICOWANDERER
Explorer
Feb 25, 2014
As near as I can tell 12-1/2 meters off the ground.
MEXICOWANDERER
Explorer
Feb 25, 2014
The Occasional Power Supply and portable battery charger
GordonThree
Explorer
Feb 25, 2014
That's going to be an impressive flood light, hopefully with a "bulb" that won't need replacing for the next ten years.
MEXICOWANDERER
Explorer
Feb 25, 2014
This is going to be free-air mounted with a 12-watt 80 CFM ball bearing fan mounted against the side of the heat sink. Silver Oxide heat sink compound. Mechanically attached chips. Twelve of them. 120 watts of these chips put a 150 watt Metal Halide (Hubbell) lamp to shame. But that's not the idea. The idea is this is for 12 volt operation, without inverter. Theft resistant. Our little uñados will spent a whole night digging out an inverter. The battery box is steel welded to a 4" diameter steel post (lamp) sunk deep in the ground. No room in the box for an inverter. Designed to light up a beach at night (where RV'ers Park).
NinerBikes
Explorer
Feb 24, 2014
Redsky wrote:
Wattage is irrelevant to the amount of light output from LED's and even for the old tungsten lamps. An inefficient driver is going to take more current and produce less light. A higher Wattage tungsten lamp is going to be more efficient so a single 150 Watt lamp provides considerably more light than two 75 Watt lamps.

Electronic devices do not do well with heat and heat sinks are only a partial solution if the fixture itself does not provide for air flow around it. It is why CFL bulbs when used with the driver on the top (as with a recessed can fixture) will fail much more quickly.

I focus more on the color temp which varies widely with the different LED's being manufactured. The higher the Kelvin rating the closer it is to approximating sunlight.
Up to 5000K, then it goes blue, violet, and UV.
Redsky
Explorer
Feb 24, 2014
Wattage is irrelevant to the amount of light output from LED's and even for the old tungsten lamps. An inefficient driver is going to take more current and produce less light. A higher Wattage tungsten lamp is going to be more efficient so a single 150 Watt lamp provides considerably more light than two 75 Watt lamps.

Electronic devices do not do well with heat and heat sinks are only a partial solution if the fixture itself does not provide for air flow around it. It is why CFL bulbs when used with the driver on the top (as with a recessed can fixture) will fail much more quickly.

I focus more on the color temp which varies widely with the different LED's being manufactured. The higher the Kelvin rating the closer it is to approximating sunlight.
GordonThree
Explorer
Feb 24, 2014
MEXICOWANDERER wrote:
Here is a link to the monster that I am going to build. Found the chip hardware mounting in a Jameco catalog.

http://www.allelectronics.com/make-a-store/item/HS-176/17.25-ALUMINUM-HEATSINK/1.html

That's a serious looking heat sink! Those fins appear close together in the picture, definitely a setup for forced-air cooling from one or more fans.
GordonThree
Explorer
Feb 24, 2014
MEXICOWANDERER wrote:
How is the RFI factor. I'm sure you addressed it but my eyes are too weak to discern the parts numbers :)

I tested with a weather radio and an FM radio, there was no discernible difference in reception of stations on either radio with the LEDs on or off. I've never received any tv channels over the antenna while the coach is parked at my home, so I could not test that reception.