I have a USB charger connected to the accessory socket next to the ignition key. When I turn off the ignition the power at this connector cuts off after 60 seconds.

Yet, when I connect two LED lights with 0.8A each the power never cuts off. With just one light connected it does shut off.

I can only guess that there is something 'magic' going on to support the BMW battery charger at this port.

Any other guess?