I recently bought a little gadget that plugs into a fag-lighter socket, and has a digital display of Voltage.
When I turn the key to "Acc" with engine stopped after standing for 24 hours or more, it displays 11.1V which increases to 14.4 when I start the engine.
This is not a no-load voltage, because the A/C fan, auxiliary coolant pump and various electronic services come on as soon as the key is turned. The battery is very large, 90AH.
Is that normal for a battery in good condition? 11.1V seems rather low.
Edit
having researched this further, all the tables I can find for voltage:battery state of charge are at no-load, so I will try my DMM on the battery terminals with (almost) everything off and see how that compares to the gadget reading on ACC. It looks like 12.5v would be an reasonable no-load voltage in winter, and 12.6 in hot summer.
When I turn the key to "Acc" with engine stopped after standing for 24 hours or more, it displays 11.1V which increases to 14.4 when I start the engine.
This is not a no-load voltage, because the A/C fan, auxiliary coolant pump and various electronic services come on as soon as the key is turned. The battery is very large, 90AH.
Is that normal for a battery in good condition? 11.1V seems rather low.
Edit
having researched this further, all the tables I can find for voltage:battery state of charge are at no-load, so I will try my DMM on the battery terminals with (almost) everything off and see how that compares to the gadget reading on ACC. It looks like 12.5v would be an reasonable no-load voltage in winter, and 12.6 in hot summer.