life expectancy of led lamps

[murdock]

i have been installing lots of led lamps...and of course as with any installation things fail...especially lamps.

what happens if a lamp pops within the 6 month of installation? (according to the CPA)

because led lamps are suppose to last longer than the normal lamps...this was the first thing the customer pointed out to me...when i took the lamps back to the supplier...the fisrt thing they asked was...does the installation have surge protection...and lucky for me on this particular installation it has everything from surge protection to phase failure to line unblance you name it...so they dont have a leg to stand on.

so just a word of warning...if you decide to spend R80+ on led lamps...or R300+ for led flood lights...consider fitting surge protection...or ask the supplier what the requirements are if the lamp pops within the 50 000hrs (which if used for 10 hours per day should last more than 10 years) because they dont last that long...and the reason they dont last anywhere near that long...as indicated by the supplier...SA has a "dirty power"

another tip...i always write the date on electrical equipment...be it lamps...day/night switches...e/l units...because sometimes the equipment is already 8 months old at the date of purchase...learnt my lesson the hard way with this one.

[Blurock]

How do I install surge protection for my house and what would the average cost be?

A friend has just lost a fridge, microwave and TV due to power outage and the surge afterwards. Not sure if the insurance will cover it.

[adrianh]

Life expectancy of a led lamp is really a difficult thing to define. Is it when all the leds are dead - is it when only 10% of the leds are dead or is it when the rated output of light falls below say 80%. Some led work wonderfully for 10,000 hours and then their output drops off sharply. Some cheap leds are overdriven so they work nicely for 1,000 hours and then they fall down to 30% of rated power. The big problem with led lamps is not so much that they blow outright, but it is that their power decreases dramatically before their quoted life expectancy is over.

I suppose the answer lies in using a trusted supplier such as Osram or at least use a supplier that fits good qualitity leds like Cree or Philips etc.

[Justloadit]

A very good indication of a quality LED lamp, is the temperature at which it runs at. Maximum life span for an LED requires that the body where the LED leg solders to the PCB, must not be higher than 60 Degrees Centigrade. Every degree above this is a factor in the lifespan, and is not a linear function but quadratic in nature. In other words the higher the temperature the quicker the LED system fails.

The very cheap LEDs do not have sufficient heatsink to ensure the correct temperature of the LED, and cause premature failure.

Another case with the cheaper LEDs, is that they use a RC, circuit to drop the mains voltage, basically they use the reactance of a capacitor to cause a voltage drop to the LED circuit, however, the reactance of the capacitor, which translates to an equivalent resistance, is based on the frequency of the supply signal. Under normal conditions, it is 50Hz, and the slow rise in the wave at 50Hz, causes the capacitor to react with a known resistance to the change, however, if there is a surge on the line, the speed of the rising surge voltage, passes through the capacitor, as it is now seen by the capacitor as a higher frequency, so its reactance becomes much much smaller, this in turn means that a higher voltage and current now flows through the LED, causing it to exceed its design parameters and fail.

The better quality LED lamps, have an internal switch mode PSU, which is immune to this, and unfortunately can only be identified once broken open, and exposing a miniature internal transformer. The more expensive LEDs have this type of supply. The top of the range lamps, have internal temperature measurement of the LED, and adjust the power to the LED to preserve the LED.

Also note that not all LEDs are dimmable, and those that are, require a purposely built dimmer.

[murdock]

How do I install surge protection for my house and what would the average cost be?

A friend has just lost a fridge, microwave and TV due to power outage and the surge afterwards. Not sure if the insurance will cover it.

dpends on the cause of the surge...some people dont know there is a difference between surge protection and lightning protection...if for example the cables are stolen in your road or sub station...chances are that they cut the neutral before the phases...which causes power surge (increase in voltage...ranging from around 500volts and up) which will blow your electronic devices...fridge...micorwave...tv etc...you need to install products supplied by clearline for this type of problem...not too many people understand surge/lightning protection...so getting an electrician in to install surge protection...could be an expensive waste of money.

[AndyD]

Surge protection is a complex field but the simplist way to go is a good quality UPS. This would contain surge protection, lightning protection, under-voltage and over-voltage protection all in one package. We've used UPS protection for LED installations in the past as it's worked out cheaper and more convenient than installing all the individual protective devices separately. I can't remember the exact model we used but it was manufactured by APC.

[murdock]

andy i do believe it boils down to the cost...a good quality on line ups...would cost a small fortune...but as i am typing this thought went through my mind...taking into consideration that an led only draws a few watts...it would only require a small ups...do you think people would want to pay the additional expense?

[AndyD]

I guess it depends on the environment they're being fitted. We used a UPS on an installation where overvoltage, lightning and surge protection was specified as a requirement.

The UPS supplied about 160 fittings and it was very small one, same size you often see powering a single PC or laptop. I stand to be corrected but I think the cost was <R1300.00 whereas the individual protective devices would have cost nearly double that. There are similar no-name UPS's available at around R600.00 you could investigate but we paid extra for a good brand.

[Justloadit]

Just remember the internal battery in the UPS has a short lifespan, approximately one to two years. Most of the smaller UPS, can not operate when the battery dies, and requires the battery to be replaced.

[murdock]

i think the price difference has a lot to do with the type of ups as well as the brand...a ups which is supplying a constant stabilised voltage cost a lot more than the ones which switch when the voltage is interupted.

[AndyD]

UPS battery life is often as high as 5 years if the batteries are the gel type and the UPS is a good quality unit which uses some intelligence to manage the charging of the batteries. Cheaper batteriesand UPS's do result in shorter battery life... I know because one of our office UPS's was a Makro cheapie and they lasted less than 3 years.

The price difference in UPS's of similar KVA ratings is very much relative to the type of UPS and the quality of power protection it offers.

[Blurock]

What's the use of these surge protection plugs you see in supermarkets?

[AndyD]

If you buy 4 or 5 of them along with some leather thong you can make some very fashionable jewelery.

Seriously I'm not sure because their description is so vague and there's rarely any serious specs attached to them. I'm guessing they might be supposed to offer some kind of lightning protection or even general surge protection but without knowing the clamping voltage and the type of components used in them it would be guesswork.