Jack Klarich
Guest
Take this from a guy that made a living testing batteries for the Navy for over 20 years.
You do have a short, when a cell in a battery fails the plates in that cell all short together effectively making 1 cell of the 6 useless.
This will cause all the symptoms that you are getting.
I have had a cell short and shut down all electrical power in a SUV while running 80 MPH in heavy traffic.
Not a fun situation.
A load test will verify this.
The only way to fix it is to replace the battery.
My 2 cents.
Bob
IMO, it is too bad so many batteries are sealed now days
In the past it was fairly common to be able to test individual cells and see right away you had a problem
A Hydrometer test to check each cell, We also used a Sun Machine battery test station to check dead shorted cells, this took all of the guess work out of the equation