i am using SMD LEDs having a supplyVoltage of 3v so that i can use a coin cell as a power source.The number of LEDs are between 40 to 50.Probably a good idea to say something more about the LEDs such as current rating or power rating, voltage drop and how many LEDs you need to have in each string and the number of strings.
The current per LED should not more than 3mAi am using SMD LEDs having a supplyVoltage of 3v so that i can use a coin cell as a power source.The number of LEDs are between 40 to 50.