- Joined Jan 17, 2008
I had an emergency led lamp consisting of 120 5mm white leds. The unit was powered by a rechargeable 12v 2Ah lead battery. When the battery finally packed in I removed it and via a plug-in connection attached a mains power supply giving 12v at 2A. This worked fine. Then to make the system more compact I replaced the power supply with a lightweight switching power supply as used to power a 12v external hard disk. The leds lit up alright at the beginning and then the lights started flashing. My query is why does this happen? Surely if there is enough continuous power from one of these units to drive the motor in an external hard disk then why do the leds flash?