I am using a SainSmart 5V 2-Channel Relay Module for Arduino to drive a hot plate (110V, 1000W).
I plugged my Arduino VCC and GND to the VCC and GND pins of the relay board and I drive both relays simultaneously through one of the digital output pin. The relays are controlling both the phase and the neutral of the cooking plate. In order to control my temperature, I turn the relays on or off in a 15 seconds window.
Twice, already, my relays appeared to die. The LED still works, and I still hear the noise when it is toggled, but the contact is not made anymore.
What am I doing wrong? How can I fix it?
Best Answer
If possible increase your time base to double or triple the 15 seconds.
A better relay will last longer- you could also go to an SSR, but it would require a fair size heatsink to dispose of around 9-10W.
The lifetime of a mechanical relay will be specified in the data sheet, but typically it’s around 100K at full load, so at 15 seconds that’s a bit over 2 weeks 24/7. If it’s 50K, obviously half that.