Interesting, as are all your posts! Your system is a full order of magnitude bigger than mine, which has a 100 watt solar panel and the greatest engine charging of my 2 house batteries I have observed is 6 amps.
I don't think there is a larger relay. I spent a fair bit of time looking for the kind of selenoid or solid state disconnect that people with larger motorhomes have posted pictures of. Just now, I went looking for the .88 amps you mentioned. I connected the engine battery through a multimeter set on its 10A range and put another multimeter on 10A in place of the jumper wire. I observed about 0.4 A coming in from the house on the jumper meter and 0.35 charging the battery. With no current coming from the house, about 0.05 A flows out of the battery, which must be the parasitic current of the vehicle. With a door open and courtesy light on, an extra amp came in from the house solar system and didn't go into the battery.
The relay I replaced with a jumper is called the "Trailer battery charge relay" (E). There is a 40 A fuse also named "trailer battery charge relay" (8).
No current rating is given for the relay in the book or on the relay itself, otherwise so well self-documented. However, I happen to have a spare one still in its package that is rated at 40 Amps.
I find it interesting that the system is set up for 40 Amps but only achieves 6 A of battery charging. Maybe I could benefit greatly from one of those DC to DC voltage changers.
I like my little jumper better than a trickle charger. Such an efficient simple solution. No converting DC to AC and back again; only 4 inches of wire! I accidently made it just long enough to work with my clampmeter.
What the heck is the "auxiliary battery relay" (fuse 20 in the photo) for?
