Still finding surprises on a used boat.

It has a Freedom 25 Charger/Inverter, controlled by a Link 2000.

When I turn off the charger using the button on the Link, the charger
only stays off for a few minutes. When the fully charged battery drops
to about 13.6v, the charger switches back on. It's subtle, because the
"charge", "accept" and "float" lights and the "charge" light do not
light. If you're not watching the voltmeter, you won't notice.

Is this the way it's supposed to work? The manuals imply that this is
the default option that can be overridden by DIP switches on a manual
control panel that I think the Link replaced.

The only way I can shut down the charging is to kill the 110 to the
Heart. Unfortunately there is no separate breaker on that line.