I agree with watch teh 12 volt battery voltage
Another thing the xantrex look at waveform of "shore power" some generators (IE: Inverter units) are nice cleans sine waves.
Many "Contractor" open frame types are downright scary waveform wise
With the latter the inverter may refuse to pass power and charge batteries.
As for the 15 volts
You may need to edit/adjust battery type or pramaters in the menus
Or you might have a leaky regulator pass transistor.. I did.
What did i do about it? I put the charger into standby and used a progressive Dynamics Wizard (9180+wizard) converter.
I liked the PD Wizard better than Xantrex's programmers anyway.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times