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About the Quality and Warranty of Filament LED Bulbs
Time:2015-7-29   Author:YunsunLED

As filament LED bulbs are getting more and more popular, many customers stepped into this new business, but there still many customers especially those who are mainly doing lighting projects hold on their steps, because they know the lifespan of filament LED bulbs are much shorter than those normal ones.

In order to make you to understand more about filament LED bulb, here we list out the quality factors of it.
 First of all, lets look at the construction of filament LED bulb, see the picture below:
We can see there are 5 parts, but only 3parts affect the lifespan:
1.LED Bar: It is the main part which affects the lifespan;
2.Driver Inside: 
3.Gas for Heat Dissipation:  Nitrogen (N2) and Helium (He)
We know, heat is always the factor which affects the lifespan of LED lights, so the design for heat dissipation is very important to all kinds of LED lights, for filament LED bulb, the heat emitting from the LED bar is conducted from the bar to the glass cover by the gas inside. The thermal conductivity of the Gas and Glass cover is very weak, so the most effective way to lower down the heat is to lower down the heat output from the heat source -- LED bar.
Normally, there are 20-30pcs LED chips mounted on the base board which made of Sapphire, Ceramic or Bronze. The ultimate heat sourced from the LED chips, then conducted to the gas by the base board and yellow phosphor.
The best way to lower down the heat output is to lower down the input current to each single LED chip mounted on the LED Bar. For an instance, the rated input current for a LED chip in a normally bulb is 20mA, for a Filament LED bulb, it will be set in 10-13mA to lower down the heat output, it is the regular current data in the market, but Yunsun set it in 8-10mA for a longer life.
8-10mA to each single LED chip makes a much much longer life as the heat is  proportional to the square of current. But it will also result in a lower lumen output, in this case, Yunsun use big chips for our LED bar, normally, people use 9*10mil sized chips in LED bar, while Yunsun use 9*12mil even 12*15mil sized chips for a higher light efficiency and higher lumen output, of course, the cost will be higher, but it deserves to pay 10-20% higher price to get 30-50% longer life.
There are some low priced filament LED bulbs in the market, they use just 8*8mil LED chips even smaller and higher the input current to each single LED chip to get a reasonable lumen output, they can sell it at very low price as their cost is much lower, but lifespan is also much shorter.
Normally speaking, the lifespan for the filament LED bulb with regular input current 10-13mA is about 1.5 years based on 24hrs continuously lighting every day. Yunsun filament LED bulbs could be 2-2.5yrs with 8-10mA current input, of course it would be longer if you just light up them no more than 12 hours per day.
As daily working time affects the lifespan very much, we suggest our customers to give different warranties to their different projects or customers:
Longer than 12hrs working: 2 years
8-12hrs working: 3 years
5-8hrs working: 4 years
Less than 5hrs working: 5 years