If your battery is the original or you have a newer one that has not been disconnected while in storage, then your battery is dead. If original just replace it. The converter takes the 120VAC from shore power and creates 12VDC. If you do not have shore power then your converter will not charge the battery. Take the battery to an auto store and have it load tested. When not using it, you need to either shut off the battery disconnect switch or disconnect the negative side of the battery.
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