cyberiankhatru wrote:
I figure the battery is toasted.
Yes it likely is. 20 V is probably the open circuit voltage of the charger, indicating that no current is flowing to the battery anymore.
Two lessons might be learned here:
A good automatic tender type charger is not very expensive; the few extra dollars would have been money well spent.
Regardless of what the batteries are connected to, they should be checked for water and voltage about once a month.
I fully charge mine then disconnect (switch).
A routine running of the truck and gen once a month keeps them topped up.
'07 Damon Outlaw 3611
CanAm Spyder in the "trunk"