46 LED lamp for £3 - at Morrisons.....

[PetiteFleur]

Went to Morrisons this morning(too wet for the boat) and spotted a 13.5cm diameter lamp with 46 LED's powered by 3 AA batteries for £3(less batteries). Couldn't resist it and when batteries fitted I was very impressed; you can switch from 23 or 46 LED's and it's certainly gives a very bright spread of light. I suspect with three in series you could use the boats 12v system and it would light the saloon. Or use as standalone lamps in dark corners. Possibilities are endless....... I'll be back to get some more!

 

[VicS]

It would be interesting if you could actually measure the current it takes.

 

[PetiteFleur]

I wish I could but I don't have a suitable meter - mine doesn't seem to do Amps - only DCv; ACv and various Ohm scales. I'll leave it on and see how long the batteries last.

 

[trouville]

I have a 12v 20 LED lamp which uses 1.3w or a bit of an amp!!One amp will last all evening with some to spare!!

Gives a great light a bit hard but very good.I still use tungsten bulbs and halogen lamps for reading,its far more than bright enough but not nice for reading

When LEDs were first invented a side effect was to tone the skin with the rapid puls gets rid of wrinkels!!

No idea if those early observations are valid with chinees LEDs today??Very good light at very low power ideal for the wet grey north of Lyon.Its raining AGAIN!!!

P.S My 20 LED halogen replacement size lamp cost 4.50euros at Lidel & a 60 LED rechargeable "car" inspection lamp 14.50 euros

 

[davidrainsbury]

Thanks for the hint. I'll be off to Moggies in the morning. /forums/images/graemlins/smirk.gif

 

[PetiteFleur]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE

Mmm - don't be too hasty, it's been on for 7 hours now and 11 LED's are apparently failing and are much dimmer than the rest. I'll report more in the morning..........

 

[Anonymous]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE

[ QUOTE ]
Mmm - don't be too hasty, it's been on for 7 hours now and 11 LED's are apparently failing and are much dimmer than the rest. I'll report more in the morning..........

[/ QUOTE ]As you probably know, true 'white' LEDs are not possible to make, so these things are made by using phosphors (as in a fluorescent tube) which are excited by invisible light from the LED itself. When they degrade rather than fail dead it is usually because they have been over-driven. That's why if you are buying LED nav or cabin lights it is best to insist on an onboard voltage/current regulator though beware as they can cause interference with the radio.

Another (and more probable) reason for such a large number of failures is that part of the matrix has a bad connection. Are the failing lamps in any logical pattern, or entirely random?

 

[PetiteFleur]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE 2

Hi again, it's now 17 hours and the 11 failing LED's are still much dimmer than the rest; which are still bright but not as bright as earlier. The failing LED's are in a random order, it's battery powered(3 x AA Alkaline). BUT, I've just fitted 3 fresh batteries and ALL the LED's light up very bright! Why?

 

[steve28]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE 2

the leds they are using are lower grade hence the price, same thing with the argos ones, if you buy the a grade ones from ebay or similar you dont get the fade or flicker but you do pay more for the leds

 

[bedouin]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE 2

Driving LEDs in parallel (as yours must be) is actually very tricky. Because they are non-linear devices then if you wire a dozen in parallel the current through them (and hence the brightness) will vary dramatically due to the variation of the individual LEDs.

Usually this can be countered by putting a small resistor in series with each LED which (by Ohms Law) tends to even out the current flow through each LED.

What you are probably seeing is that as the voltage of the batteries drops some of the LEDs are being starved of current and so are dim. You will probably find that if you put new batteries in then they will all be fine again.

 

[Burnham_Bob]

Re: 46 LED lamp for £3 - at Morrisons.... UPDATE 2

just a thought, we eventually got two hurricane lamps off the internet for £2.50 each and they provide a good light in the cabin without draining the battery! Low tech is sometimes a good idea.

 

[tinkicker0]

A couple of months ago I went to Wilko's and bought a 2 pack of stick on 4 LED spotlights which run on 3 AAA batteries.

Stuck them on the bunk bulkheads above the pillows and we use them for reading lights that won't disturb other sleepers or emergency lights if the electrics fail.

We tested them out using rechargeable batteries before fitting and they stayed lit for a full 24 hours and the batteries were still good.