This is my first post. I have been coming here for years though.
I am designing a relay board for my motorcycle to control power to various accessories - lights, heated gear, horn, GPS, etc. It's a pretty straightforward design... some terminals, fuses, and relays. Nothing really new except the goal is to make it small because my bike doesn't have much space and it's a good excuse to practice PCB layout.
Right now I have a few channels and relays that can be individually controlled by various switches. I figured the maximum current any channel will realistically see is 10-12A so I went on digikey and searched for 12VDC automotive relays rated for 20A and higher.
I ordered this little guy which is rated at 30A: https://www.digikey.com/en/products/detail/omron-electronics-inc-emc-div/G8N-1H-AS-DC12-BY-OMR1/6817243
When I got it in the mail I honestly don't believe this is rated for 30A. It's so tiny. Every other automotive relay I've dealt with is HUGE. I've also used 10A relays that are 3X this size.
Everything I'm reading says this is fine, and that if the switching current rating is 30A then the continuous current rating is probably even higher. I still don't believe it though, because it's so small. Even the power pins are small, they look equivalent to 20 or 22awg wire.
I kept looking around and found some other relays (similar form factor) that specifically say in the datasheet they're made for lights and heaters. The one linked above says it's used for window motors and such (things that get used for maybe 5-10 seconds at a time). But just looking at the numbers, there's nothing that says it can't be used continuously.
Am I missing something here? Would this thing be fine with a 30A resistive load running through it for 6 hours or would it just melt? Please enlighten me. There doesn't seem to be any link between size and current carrying capacity. And there also doesn't seem to be any reasoning for the datasheet numbers and the "typical applications" either.