Dead battery in 2018 T@B 400 - Solar not working

We have a 02/2018 T@B 400. I have been having problems with the solar and think I may have killed the battery. I just pulled the black plastic cover off, expecting to see two 6 volt batteries but found a single 12volt 225AH battery. I tried to have the battery tested at my local auto parts store but it would not register. On Monday I’ll take it to my local battery specialist to see if they can save it.

Our single 12 volt Harris AGM in our 2018 400, went belly up the first part of this year.  After conversations with Harris, it had a 12 month warranty and that was up.  They no longer stocked that battery and wanted near $700 for 2, 6V AGM replacement batteries.  Went to Interstate batteries and got a single 12 V AGM for right at $500.  Direct replacement no need to reconfigure the wiring etc.  It is a 200 AH battery but that works for us.  Also about 10 lbs lighter.

Good news (I think) - I tookthe battery to a specialist and they checked it and said its fine. So now I just need to sort out the solar panels.

it was not depleted. I had tried to charge it but the charger indicated it was fully charged - I just didn’t trust it. So much for my local auto parts shop who tried to test it and said it was dead.

What kind of solar problems?  Have they worked in the past?  

New Zamp/Sunpower panels arrived today. Great customer service