Question about LED lights
Posted: Tue Mar 10, 2020 10:11 pm
Can 12 volt automotive LED lights be used on a 12 volt AC system. ( landscape lighting )
If they're LED's then possibly not, as many of these are DC only. Even if they have rectifiers built in 12VAC may be too much.
Bear in mind that 12VDC is simply that, 12V. However 12VAC could have a peak voltage of nearly 17V - AC voltage is usually stated as the RMS voltage, or 0.707 of the actual sine peak.
To get the peak from the RMS multiply by 1.414, and take the result into account if you're using voltage-sensitive equipment.
Tungsten automotive bulbs might expect to see 14VDC at times and given the necessarily alternating supply with zero crossing points etc I suspect you'd not have any real issues, although YMMV. However a LED with a rectifier and capacitor could apply close to the peak to the LED driver (or the LED's directly if wired in a particular way), which may cause them to fail prematurely.
Perhaps best to regulate the supply first, and provide DC. This would also allow a greater range of LED's to be used...
Apologies for the long answer!
