Pmullen503 wrote:A relay should be used when the switch can't handle the load or if you want to a low voltage circuit to switch a high voltage circuit. Otherwise, it makes sense (fewer components that might fail) to just use a switch and perhaps a fuse to protect the circuit from shorts.
That's certainly one way to use it. I typically put all my switches on a very low amperage circuit, and use that to switch relays to control much higher amperage stuff. Also to automatically switch accessories on/off using an ignition circuit. But, that being said...I'm just not sure any other than the water pump and the diesel heater would benefit from a relay, and even then, it's questionable. My WP pulls AT MOST 5A when it's running. My heater pulls 12-13 or so when the glow plug is heating up (and I'm going with a smaller heater in the new build), so even then, the switches that I plan on using are supposedly rated at 30A. The highest draw device will likely be the diesel heater, and maybe the stereo. Both of which should be well under 30A.
I'm very familiar with 12v systems. I wanted to learn how to do them so that if something happens in the field, i have the skills and knowledge to be able to fix it on the spot. I built the system in my Xterra myself, and it's never let me down.
![Image](https://i.postimg.cc/7P0JjYYQ/IMG-20210904-220529-01.jpg)
In the new build. I think I'm going to use something like the Progressive Dynamics PD60. This panel, specifically:
https://rvpartsexpress.com/product/prog ... 0b18t2l15/Two reasons:
1. It has enough fuse slots that I can run everything to it for my accessories
2. It flush mounts to a wall, and looks pretty good, in my opinion. Certainly better looking than a typical marine fuse block.