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This is not really a Grand Design issue but thought I would post it here since a lot of us use Victron gear, and inverters in general. We stopped for lunch yesterday at a truck stop and I fired up my living room AC unit off the inverter. I have done this before a few times with no issue, I keep an eye on the battery temp and open the compartment door for a little extra ventilation. Usually my draw is in the 16-1800 watt range. After about a half hour my wife commented the AC had shut off and I looked and noticed we lost AC power. The display was showing low voltage, but all of my 12v loads were working fine, and my BMV was showing plenty of power. I thought maybe it had just overheated as it was quite warm out, and figured best to get to the next camp site (an hour more to go) to get the fridge plugged back in. When we arrived I reset the MultiPlus and had the same error. I went ahead and plugged in the rig and crossed my fingers that the transfer switch would pull in, which it did, and everything was fine. Given the heat I thought it best to leave everything until today to troubleshoot further. Today I unplugged shore power and got the same error. I dug into it a bit and found my voltage was dropping from 14.4V to 10.2V across the fuse (Class T 400A). Pulled it all apart and found the fuse holder melted and fuse charred. The top half of the holder had melted, but not all the way through and the base was intact. I read the fuse resistance at around 150 ohms (rather than the .1 I would expect). I had a spare fuse (not a holder) and put it back together the best I could and everything is working fine. When I get home I will replace the holder and get a new spare, but a few questions. I am surprised it failed, and in this way. I was well below 400 amps, and the fuse did not open completely, so I do not think that was the issue. The holder and fuse are both Blue Sea, although checking my order history it looks like the holder was only rated to 320 amps. Again I would think I was well below 320 amps, and I am surprised that would fail. Connections were all tight, and none of the wiring (all 4/0 welding cable) was hot or seemed discolored or stressed at all. Do we think the holder was just defective and could not take the heat for some reason? Maybe the connection was not as tight as I thought (but I had to use a wrench to remove the nuts, it was pretty tight). Obviously I am going to source a 400A holder this time, but does anyone think I should need anything different?
Picture of the fuse here, picture of the holder will have to wait until I get home and pull it all apart again.
Picture of the fuse here, picture of the holder will have to wait until I get home and pull it all apart again.
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