Recently obtained digital voltmeter.Battery newish 3 yr old,12 yr old 80A alternator with new voltage regulator(Monarch aftermarket)
Found voltage across batt terminals 13.99 with engine idling and with engine off,immediately 13.1 V,cooled down 12.55V .
With volt gauge,the voltage drops down to 11V if the car is very hot like idling in traffic with air con and fan on.Once moving,the volt gauge moves up to 13-14V range.
is the heat sensitivity or idling sensitivity normal?Can someone post a treatise on what can be done with a digital elctrical meter which are now so cheap to buy?

__________________
Tom 2010 C250 4-matic Sport (Canada)