Review on Hamolar 2 Pack 12V 40/30 Amp Car Relay DC 5 Pin SPDT and Harness - Heavy Duty 12 AWG Copper Wires Relays Kit Bosch Style for Automotive Truck Van Motorcycle Boat - High Performance and Reliable by Cory Mosley

I used this to plug a replacement fuse box into my 71 Super Beetle, I didn't want to add any extra load to the original fuse box so I plugged it in with battery power, and it runs from a sheet fed from the fuse box. I haven't had any problems, but I only use the relay to power simple things like a low power radio and a couple of interior light bulbs. However, I think that external light will not be a problem. The included plug fits securely and provides more confidence.