Skipping the relay will cause you to run the full amperage through your dash switch. I've seen a number of dash wiring fires to know that this is not the best way to do it. If it were me I wouldn't skip the relay.
Even the factory lighting uses relays.
I would also suggest an inline fuse. I had to put out a fire in an engine compartment once because shody wiring went to ground and it was not fused. The insulation and anything plastic near it caught fire when the wire turned into a heating element.
Take the total wattage of your lights and divide 12V into that number to get your amperage. That number will help you to buy the right relay as well as size your fuse slightly larger than your load.
200 watts divided by 12 volts equals 16.6 Amps so a relay and fuse rated at 20 amps would be sufficient. Go to large and you lose some protection but go to small and you will have nuisance blowing of the fuse.
It's more imortant than many people realize. You don't want to burn your rig to the ground. Hope this helped.
Yea, mounting lights without a rely is asking for trouble. You literally WOULD want to have a fire extinguisher ready.
My setup actually uses a “Solenoid” instead of a Relay. Same exact concept, just extreme over kill, and allows more power to reach the lights, making for a brighter light.
Whatever you use “Solenoid” or “Relay”, the wiring and concept behind the wiring is the same.
You can think of either as a remote switch. The idea is to remove the “Load” off an “in Cab” switch. Basically, the in cab switch turns on the Relay, and the Relay turns on the lights.
The safe way to do this is to have a switch that is grounded on one pin. When you switch on the switch, it simply “Sends” a ground to the “Coil” on the relay. The other end of the “Coil” is connected to the “+” lead (BATT ). Then, the other 2 parts of the Relay are connected to “+”(BATT) and to the “load” or lights.
You want the relay mounted under the hood.
Using a “solenoid” is the same, except its more HD. A standard relay is 40amp, the solenoids I use are 160amp, and designed for 100% up-time.
Any way, “Google” off-road lights and relay, and you will find lots of good info and images.
By the By, you may note most sites say to use “+” in the cab switch and “Send” a “+” to the relay, instead of the ground method I listed above. Well it is true that you can use “+” in the cab switch, it adds to failure and risk. And in a “well used” 4X4, its downright dangerous to “Send” “+” on wires. The more “Ground” based wiring you use, the safer.