Troubleshooting Magnum Inverter / House Battery Issue

[Charlie]

Looking for insights on how to address a dead battery fault msg on my Magnum Inverter. I know from experience that I must recharge the house battery (LGM) before I can get the inverter and shore power connection recharging thr battery.

Unfortunately, I’m not able to get the inverter to light green that it is accepting the shore power charge. Display still reads “Dead Battery Charge” with shore power connected. I read that many have had to reset the Magnum inverter but the using the reset button on the front wasn’t successful. I also read there is a 2nd master reset but can’t locate it on my model.

While I checked all the fuses in the panels nearby. I feel I may have missed a fuse that connects the inverter to the shore power.

Lastly, I came across this plugin unplugged in the compartment near my inverter and can’t identify what purpose it performs or where it might go.

Appreciate any leads on the root of my problem. Currently, recharging the battery back near 100% before I reconnect.

[Scalf77]

Seeing as the Dead battery message means the battery voltage is below 9 volts. So like you said yo may need to get it above 9 volts using either solar or charging via your ACR. I suspect from what you have said that you have done that and it will not reset itself, (which is what generally would happen)

I would get a DVM and measure both the battery voltage and the voltage at the terminals at the inverter. The two voltages should be 0.5 volts within each other.

The reset button(soft reset) is above the ports for the remote, temp sensor, network. A hard reset entails you to remove both AC power and DC power.

A class T fuse holder should be between the inverter and battery


The fuse itself looks like this

The disconnected part is a micro relay, not sure what it is being used for, but it would plug into a socket that fit the tabs on the back.

-greg

[Charlie]

Greg-
Thanks for taking the time to break it down for me. I removed the battery and it took it for a diagnostic and it’s running great. 13.3v and reconnected it but still receive the same dead battery error msg. I assume it has to be a fuse now or the hard reset to the inverter. I read that the Magnums have two resets but can only locate the front button.

I believe the image attached is the class T fuse but it looks to be in good shape.
Charlie

[Scalf77]

That is actually a ANL fuse, which is OK, but the connection does not look good on the right side. The terminal is up on the edge of the fuse not making good connection. It needs to be flat, that is actually a little on the dangerous side. It is possible that this connection is bad and causing a issue at the inverter. Did you measure the voltage at the inverter. I know room is tight. The second reset, is the hard reset, no button needed (Remove AC And DC) reconnect.

-greg