Katman
Thanks for the informative post. Glad you where able to get your Xantrex back!
I went out to my Xantrex and pressed the charge button and it turned the charger off (I was on shore power). I stand corrected when I stated the buttons on the Xantrex are not working. I did not try the invert yet.
What makes me think the issue is with the remote panel is the fact that when I plug the remote panel into the cable to the Xantrex the Charge LED will light for approximately 30 seconds then goes out. I'll try the phone cord idea one more time though. Also, was looking thru the Xantrex 458 videos on YouTube, One gent suggested jumpering the two pins on the face of the Xantrex to get the panel back. The pins basically force the charger on. You could rig up a switch to those pins and use that to turn on/off the charger if you did not have a remote panel.
Wanted to also thank Doug for the suggestions, I did try the disconnect EVERYTHING and shut down for XX minutes, again, could not hurt to try it a 2nd time. I think I'm also going to look into a new battery temp sensor. I believe mine is non operational because the float voltage does NOT change at all when I disconnect. Float currently hovers around 13.5 BUT should increase when the temps are 32 deg/F or below BUT then again, IF the control board is partially cooked it MIGHT also effect the temp sensor. The sensor itself is the one that you attach to the negative battery post. I also see posts about how those can go bad and in some cases run voltage back to the com board popping a chip. A properly functioning B.T.S. helps.
I do understand that the Xantrex Freedom 458 is indeed 12 years old but they are still manufactured. I saw a youtube video that stated the 458 was manufactured in 2018.
Time2roll, Thanks for the URL. I believe I should be looking to just find something to desulfate at the moment.
Again, thanks for all the suggestions/idea's
Hopefully, a Xantrex TECH will run across this post.
rm