Originally Posted by jpzb
thanks for the help. I tested with the voltmeter and got 8.5 (not plugged in) and 13.9 (plugged in). then tested again a few minutes later after leaving it plugged in and got 10.5 (not plugged in) and 13.9 (plugged in). So I left it plugged in for a couple hours and still got 10.5/13.9
8.5 volts anytime on a 12 volt battery is a very bad sign.
Not taking a charge after that full discharge is even worse.
It sounds to me like that battery is cooked.
Since each cell contributes 1.5 volts to the internal bank, you have more than 1 cell "bad."
Besides needing a new battery (for sure), I am concerned that it is also possible your converter boiled your MX free battery dry.
Did you dry camp your battery dead and leave it that way for any length of time? A heavily sulfated battery (totally discharged) may not take a charge from a "good" converter. A "bad" converter can destroy a "good" battery by never dropping the voltage as the battery tops off.
If you can put your finger on, "Yep, I thought the battery would last the weekend" then forgot to plug the camper in when you got home; a new battery will get you up and running with no other issues.
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