Running them off of a 80 watt outdoor lighting transformer, doesn't generate
the heat it does from a car battery because the transformer is very low
amperage. I was hoping for a little heat for the winter months but no luck
there. I load them at 20 watts each, in other words I put 4 of them on a 80
watt powersupply, thus 20 watts each..........Just like the outdoor setups
for your yard, same transformer, except the one that normally comes in the
plastic Malibu light or whatever the name brand is normally 40 watts which
would be enough for 2 lights, I needed 4 and they sell bigger ones up to 200
watts. What I found is if you put more lights on the circuit than the
transformer can handle it will overload and shuts off until it cools back
off. Thermal fuse protected.