Hi,
I use a trik-l-start myself.
My Ford v-10 had a sixty amp fuse for the "house" charging circuit. After I blew it three times I moved to a 50 amp auto reset breaker.
In my case (2004 E-450) there was a solenoid which closed when the ignition switch was turned on. I do see up to 70 amps of charging if I'm running my inverter *hard*. I can't imagine that tiny relay in your RV carrying much current. Are you sure it doesn't operate an external solenoid?
I added a 2nd charging path to mine and took over manual control by adding two switches to turn the solenoids on and off. I did that because I have two battery banks.
The solenoids draw 0.88 of an amp each when they are on.
