Welcome to Smarteefi Support Forum, where you can ask questions and receive answers from Smarteefi staff and other members of the community.

Please visit our FAQ page for frequently asked questions.

Multipule LED lights on one output

0 votes
Why you do not suggest connecting multiple LED lights on one output?
Say I have 4 pannel lights each of 15 watts, and total power consumed is 60 watts Is it not within the capacity?
Can you please explain the technical reasons and calculation for capacity of each gang.
asked Nov 7 by kumar_9669 (160 points)

1 Answer

+1 vote

Its because LED is a capacitive load and need a very high inrush current in the first millisecond when it switches on. Please google keyword "LED Inrush Current", you will get this link https://adlt.com.sg/%EF%BB%BFled-driver-inrush-currents/ . 

Following is the copy paste from the link for study of 2 different LED drivers.

"For a typical 150W, 0.7A LED driver, Philips Model 9137012116, used in various CREE luminaires, the inrush current is stated as 130Amp for 165 Micro Seconds. It is suggested that up to 7 -10 of these drivers be used / per 20A C curve MCB, however it will depend on the individual circuit impedance.

For a typical 220W, 1.05A LED driver, CREE Model LE098X01 used in CREE High Output Edge luminaires, the inrush current is stated as 80 Amp for 1000uS (1mS). It is suggested that up to 6 – 8 of these drivers be used /per 20A C curve MCB, however, it will depend on the individual circuit impedance."

When multiple LED lights are combined it further multiplies the inrush current. Although switch will work as it is still under rated current after 1st msec, however that inrush current will damage relay contact slowly will affect the life of relay. So a relay expected to work 10 years may get to work say only for 2 years before its contacts gets damaged and it remains ON all the time after that.

answered Nov 7 by sfiadmin (10,590 points)