BlueChip
Well-Known Member
There was a thread here a few weeks ago about LED bulbs for the Davis automatic anchor light.- http://www.ybw.com/forums/showthread.php?t=281135&highlight=davis+led
One specialist supplier was offering LED'S for about £16 each when similar looking devices are available on eBay for about 70p.
Some on here were reluctant to accept that these low cost LED's can be suitable and theories about brightness, consumption and the ability to stand voltage overload were put forward.
I thought I would check it out and ordered two bulbs from eBay supplier
http://www.ebay.co.uk/itm/300565859042?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 these cost me just £1.59 for two with free p& P
These just arrived and I have been playing with them and comparing them with the standard tungsten lamp fitted to my Davis lamp which I know performs well and is usually by far the brightest anchor light in the anchorage.
I have a digital adjustable voltage power supply where I can dial in 12.0V and measure the current drawn, so first I measure the tungsten lamp. This drew 0.19A
I dont have a light meter, but there is a very handy Android app "Light Meter 1.4" that provides an analog meter scale of 0-100 Lux. With the meter about 1m away from my Galaxy S2 phone I measured 80 Lux.
I swapped the tungsten bulb for the LED, it fits the lamp holder without any modifications and it was immediately obvious that the LED is actually significantly visually brighter than the original tungsten lamp.
I made the same measurements using the LED, it drew just 0.12A and gave a reading of 100 Lux on the meter. There was no obvious falling off of the light as the lamp was turned, even though there LED's are fitted at 90 degree angles, I think the Fresnel screen must disperse the light. I did notice that the LED position wasn't in the optimum position to be lined up for the clear centre ring of the Fresnel, if it was the lamp would be even brighter.
To see what the over voltage handling of the LED I wound up the volts on the power supply expecting the lamp to fail, I got to 16V and held it there for some time but the LED remained lit. It seems that even these low cost devices must have some over voltage protection, the current consumed did increase though with higher voltage. I don't consider this important because I wont be charging when I am at anchor.
Finally, the bulb is polarised but my Davis light cigar lighter plug was wired correctly so I didn't need to make any wiring changes.
The tests are hardly scientific but they do reinforce what I saw visually.
So my conclusion is you pay your money and take your choice, £16.65 plus shipping for a 'marine LED' from a marine supplier such as Boatlamps or £1.59 for two regular LED's delivered from eBay. On the basis of my tests the low cost solution will perform at least as well if not better than the standard bulb.
I'm planning to be away this weekend and will try it out on the water.
One specialist supplier was offering LED'S for about £16 each when similar looking devices are available on eBay for about 70p.
Some on here were reluctant to accept that these low cost LED's can be suitable and theories about brightness, consumption and the ability to stand voltage overload were put forward.
I thought I would check it out and ordered two bulbs from eBay supplier
http://www.ebay.co.uk/itm/300565859042?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 these cost me just £1.59 for two with free p& P
These just arrived and I have been playing with them and comparing them with the standard tungsten lamp fitted to my Davis lamp which I know performs well and is usually by far the brightest anchor light in the anchorage.
I have a digital adjustable voltage power supply where I can dial in 12.0V and measure the current drawn, so first I measure the tungsten lamp. This drew 0.19A
I dont have a light meter, but there is a very handy Android app "Light Meter 1.4" that provides an analog meter scale of 0-100 Lux. With the meter about 1m away from my Galaxy S2 phone I measured 80 Lux.
I swapped the tungsten bulb for the LED, it fits the lamp holder without any modifications and it was immediately obvious that the LED is actually significantly visually brighter than the original tungsten lamp.
I made the same measurements using the LED, it drew just 0.12A and gave a reading of 100 Lux on the meter. There was no obvious falling off of the light as the lamp was turned, even though there LED's are fitted at 90 degree angles, I think the Fresnel screen must disperse the light. I did notice that the LED position wasn't in the optimum position to be lined up for the clear centre ring of the Fresnel, if it was the lamp would be even brighter.
To see what the over voltage handling of the LED I wound up the volts on the power supply expecting the lamp to fail, I got to 16V and held it there for some time but the LED remained lit. It seems that even these low cost devices must have some over voltage protection, the current consumed did increase though with higher voltage. I don't consider this important because I wont be charging when I am at anchor.
Finally, the bulb is polarised but my Davis light cigar lighter plug was wired correctly so I didn't need to make any wiring changes.
The tests are hardly scientific but they do reinforce what I saw visually.
So my conclusion is you pay your money and take your choice, £16.65 plus shipping for a 'marine LED' from a marine supplier such as Boatlamps or £1.59 for two regular LED's delivered from eBay. On the basis of my tests the low cost solution will perform at least as well if not better than the standard bulb.
I'm planning to be away this weekend and will try it out on the water.