IMO depends upon the nature of the failure. If the battery had a growing presence of unreactive lead in a cell, it may just show as something like a 60% capacity battery. However, as soon as enough lead drops off or creates a short in the battery, which can be near instantaneous, then it may have the ability to drop like a rock.
We had this experience once. We were driving to Chicago, were doing just fine, had stopped maybe five or six times for eating, gas, bathroom, etc., no issues. Stopped for gas in Gary, Indiana, and all of a sudden the car wouldnt start. Nothing. Super-low voltage. Even the towtruck couldnt get the car to start until he used a screwdriver to short the starter!
But it was totally out of the blue.
This was long before I ever had a battery analyzer, but IMO showing a battery at 60% is probably indication that it has something going on...
So IMO it is all about the failure mode. If it is a shorted cell (does the battery read something like 8V?) then Im not sure nay test can forewarn of it...
We had this experience once. We were driving to Chicago, were doing just fine, had stopped maybe five or six times for eating, gas, bathroom, etc., no issues. Stopped for gas in Gary, Indiana, and all of a sudden the car wouldnt start. Nothing. Super-low voltage. Even the towtruck couldnt get the car to start until he used a screwdriver to short the starter!
But it was totally out of the blue.
This was long before I ever had a battery analyzer, but IMO showing a battery at 60% is probably indication that it has something going on...
So IMO it is all about the failure mode. If it is a shorted cell (does the battery read something like 8V?) then Im not sure nay test can forewarn of it...