Hi Forum, I have used Arduinos for a few years although have only just joined this forum. I can see old replies to vaguely similar questions although nothing to precisely answer: would forum suggest relays or Mosfets to switch these beauties?
8-9A? MOSFET AOI510 from Digikey. http://www.digikey.com/product-detail/en/alpha-omega-semiconductor-inc/AOI510/785-1487-1-ND/3603498 Power dissipated = I^2 * R = 9*9*.004 = 324mw, maybe a little heatsinking needed.
Yes a power NFET would be good (or one for each lamp)..
You also could use a relay board like THIS: and you would not need to mount/wire FETS..
DISCLAIMER: Mentioned stuff from my own shop...
Thank you for your replies - interesting, useful and informative. I will be wiring the spotlights this weekend.
Another solution is to use a smart highside switch like this, so you can have short circuit protection and some diagnostic output.