Gerald,
1) Not resetting to zero ... sounds to me like either the charger's
ground lead is connected direct to the batteries bypassing the shunt,
or a ground lead is running from the starter battery ground to the
starter or engine block. The ground legs of your battery must have
absolutly nothing connected to them except for the shunt. No
exceptions. It's hard to not have an exception. Heavy wires from
chargers, inverters, etc. may be inconvient to route to the shunt, and
misc. devices that are connected direct to the battery as part of the
boats wiring harness, like your bilge pump, need to have their ground
wire rerouted to the shunt.

2) Dead except for green bars ... I had the same problem last month,
disconnecting and reconnecting the link 20 power lead at the battery
cleared the problem for me.

Dan (b393capt)