tands@ukonline.co.uk schreef:

You're right in that: the alternator charges the battery, so that you
always have a charged battery to start the car. So, correct charging of
the battery is dependant of the accumulator, but also of the battery and
the connection in between (voltage regulator and wires).

I don't know where you're living, but batteries 'lose' some capacity in
a cold environment. For a good battery, that's not a problem, for an old
one, it can be. It's quite easy to check with a volt-meter: the battery
itself should give about 12V (with the engine off), but it needs around
13.8V to charge properly. So if you start the engine (using cables to
antoher car I'm afraid) and rev it a bit, you should read around 13.8V
between the battery poles. If so, the battery is probably dead,
especially if the weather is cold and it's already some years (>5) old.
If not, your alternator needs a bit of attention.

Groetjes,

Maarten

Assuming the alternator isn't working (still what I'm guessing) it is useful
to know that many Volvo alternators have a separate module in them that
includes the brushes and regulator. If yours is one of them, it is much more
economical to replace the module than to replace the whole alternator. The
module is usually called the "regulator" and is available from Bosch on the
ones I'm familiar with.

Mike

You may also check that the battery , alternator, and all ground straps and
wires are clean and tight.  Sometimes a connection gets corroded and/or
shakes loose.

Jack

Group,

Tim mentioned a bunch of flickering lights a few days ago, but did not
mention warning lights during this morning's ride when car would not
restart.  Usually, no matter if the cause if battery or alternator, the
charging warning lamp (looks like battery icon) should light.

Tim,

In order of simplicity/cost (though not necessarily in order of
probability), check:

1. Alternator belts tension (probably 2 belts)
2. Alternator belts condition (if worn, traction may be poor, or belts may
not hold tension)
3. Heavy wires from battery.  Make sure the insulation is not worn off and
permitting an improper ground or short, and that the connection points
(terminals) appear solid (can't be jiggled, no sign of rust, no sign of
powdery corrosion).
4. Wires connecting to back of alternator.  Same as #3.
5. Inspect and wire brush clean all the fuses and fuse holders
6. Remove battery and have tested by local car parts store (usually a
complimentary service in U.S., your miles/kilometers may vary)
7. Many things can wear out on an alternator.  Now the question becomes how
to diagnose.  In other words, you have to remove the alternator, which is
just within the skill level of beginner.  To replace the brushes or the
voltage regulator, this is not a complete removal - as Michael pointed out,
the brushes are integrated with the voltage regulator module, with 2 screws
on back of alternator, but you might have to loosen the alternator belts and
holding bolts to get at the regulator.   However, if you do a complete
removal, then you can take the alternator to your local car parts store for
complimentary test.  This will give you additional information - you always
want more data, don't you?
8.  Of course, the other alternative is to open the checkbook and buy a new
alternator, maybe $250 U.S., plus labor to install.  Most shops will try to
talk you into a new set of belts for another $100.

I recommend that you step through 1 - 6.  Maybe it's just a battery ($70
U.S. plus your own 20 minutes labor), or belts ($80 plus your own 40 minutes
labor), or fuses (just your 5 minutes labor).  If you still have problem,
check back with group to decide if you spend $15 for new brushes plus your
labor, or $70 for the regulator, or skip to step 8.

Pat Q