40 amp fuse

[KYAvion]

Yep, this one is a DC breaker. I don’t recall the size, but I will check it this weekend.

[KYAvion]

Found the thread where I had asked about it. Trip amps is 45.

viewtopic.php?f=4&t=333

[KYAvion]

OK, saw this after the other post.
The load is anything that the battery is supplying power to. In this case, an engineer (I would hope) determined that under max normal load the current draw from the battery would be less than 40 amps. The wire is sized in accordance with the max current draw and the acceptable voltage drop at the load end. It's a balancing act. The wire from the battery to the power center is likely 6 or 4 gauge (I don't know) which is rated for more than 40 amps, but is that large due to the distance, so it doesn't drop the voltage. Remember, DC, unlike AC current, is more subject to voltage drop over distance related to the resistance of the wire.

So I checked the wire size, amd it’s only 8 gauge. Measured directly, the distance from the converter to the batteries is approximately 23 feet, so I wouldn’t be surprised if the total run one-way is about 27 or 28 feet.

[Salty]

Do you know what your max current draw will be/is?
according to the calculator I use, for 40 amps and 3% voltage drop over 28 ft, you want 4 gauge.

I used this calculator:
http://circuitwizard.bluesea.com/

if your max load is 20 amps, 8 gauge is fine.

[KYAvion]

Sorry, meant to post that the converter itself is 45 amps, so when plugged in with nothing running who knows the amps being pushed ino the batteries. As you mentioned maybe 10 amps per battery, so in this case about 20 amps.

When running off the batteries, I’d think the max load would be pushing 20 amps if lights, the furnace, water pump, etc. were all on at once.

[Salty]

Dug into the control center this evening. The schematics in the owners manual doesn't match how mine is wired exactly, but is quite close.
Of note: The kill switch is rated @ 30 amps and trips @37.5, according to the rating on the side. My interior fuse is for 30 amps, vice the 40 amps shown in the schematics. Wire is 8 gauge for charge, supply and a third wire who's destination is yet uncertain.
Something I should mention is that when I purchased this trailer, it had already been wired for 50 amps, so there may have been some creative wiring. The kill switch and fuse look original though.