On Fri, 3 Mar 2017 22:07:26 +0000, Tim Watts wrote:

Next, get a volt meter that plugs in the cigarette socket (ebay, amazon,
cheap as chips).

Drive and if it doesn't get to at least 14V your alternator (or wiring)
has a problem.

Assuming it isn't the battery (and the battery can go bad from just a very few
deep discharges, os it probably is):

Get a multimeter and measure the voltage between terminals, around 13ish on the
battery ("battery is full"), 14-something when running and charging ("battery
charges").

A multimeter also can be used to measure the voltage drop *along* a cable: if
there is a significant voltage difference (tens to hundreds of millivolts) along
a connection with the car running, then that connection is bad... So, with the
engine running, the voltage between (say) the negative battery terminal and the
chassis should be a few hundred millivolts at the very most. More, and this is a
sign that the connection is bad.

A bad connection is a Good Thing, because it can be easily fixed... usually
corrosion on the ends/terminals.


Thomas Prufer