I have purchased some cheap LED China bulbs but the LED's keep burning up. In an effort to improve them I have opened some up and done some measurements.

With a 220/240 AC input and after some resistors, capacitors and a AC/DC converter the output to the LED's is 140v DC.
If you divide this by the 36 LED's we get close to 3.9v per LED! These are 5730 SMD's and I belive this is why they burn out so fast.

If I add more LED's say 50 LED's would this bring down the voltage across the LED's to 2.8v and would this extend the life of the LED's?

I have tried this in practice by soldering a long strip of LED's and the light is still at a good brightness and LED strips do not heat up.

 

Probably...

 

I agree. They probably push them to (and past) the limit to meet some claim of brightness level, at the expense of longevity. Another fix could be to remove one and replace it with a resistor. Of course you'd have to deal with the heat.

 

Discussion of LEDs to the mains is not permitted on this forum according to the User Agreement.

http://www.allaboutcircuits.com/user-agreement/

Restricted topics. The following topics are regularly raised however are considered "off-topic" at all times and will result in Your thread being closed without question:

• Any kind of over-unity devices and systems
• Devices designed to electrocute or shock another person
• LEDs to mains
• Phone jammers
• Rail guns and high-energy projectile devices
• Transformer-less power supplies