Xantrex XC 3000 won't turn on

[PlanetExcellent]

Hello, I just installed a Xantrex XC 3000 inverter/charger in my travel trailer. I have 2 200ah lithium batteries in parallel, connected to a Victron Lynx Power In, then out to the inverter's DC inputs. Shore power connection to the Xantrex AC input; AC output to the WFCO AC distribution panel in the trailer (OEM converter has been removed).

When I turn on the inverter (using remote or front panel switch), nothing happens -- display won't light up, fans don't turn on, nothing. It did previously turn on when connected to a 120v AC input from a household outlet, so I know it works. I have not tried it on the 30A shore power connection yet. DC loads in the trailer all work from the batteries via the Lynx, so I know the batteries are putting out power.

My thinking is:
1. Ignition sensing parameter (which only allows it to run when vehicle is running) is mistakenly turned on.
2. Fuse (400A) between Lynx output and inverter input is blown.
3. Fuse in the inverter (150A?) is blown. Not sure if it's removable.

Won't be able to check these things until this weekend. Anything else I should check?

 

[sunshine_eggo]

4. When batteries are connected to your inverter, there is a massive surge of current to charge the capacitors.

The vast majority of LFP battery BMSs will see this as a short circuit and engage protection.

You need a pre-charge resistor when connecting your battery to your inverter.

 

[PlanetExcellent]

But why would the batteries be able to power DC items in the trailer, but NOT feed power to the inverter? Seems like a BMS protection circuit would affect everything downstream from the battery.

And where can I get a pre-charge resistor?

 

[PlanetExcellent]

UPDATE -- it's working now

But I'm not sure why.

I bought a multimeter and measured the DC voltage going into the inverter to see if it was getting power from the batteries. 0 volts! Aha, I must have blown the fuse between bus bar and the inverter.

Then I plugged it into shore power to verify that it was properly bypassing the 120V AC back to the AC distribution panel, and it was. I left it plugged in for about 30 minutes.

Then I disconnected shore power and turned on the inverter to try battery mode again, and it worked. I measured DC voltage at the inverter inputs, and AC flowing in the AC output cable. My AC loads (microwave, TV) worked perfectly from the batteries.

My theory: While hooking things up I might have disconnected/connected the remote while the inverter was switched on; maybe that caused a problem. And maybe the act of connecting to shore power triggered a reset.