"D.M. Procida" wrote in
message
...
alan_m wrote:

On 03/03/2017 20:03, Joe Bloggs wrote:

6. More than once recently though I've stopped the car for a few
moments
after driving several miles, and will find that it doesn't start and
needs a push to get going again.



That wouldn't explain number 6.

A few miles on a uncharged battery results in a still uncharged battery

The battery on both those occasions was charged well enough to start the
car.

That does suggest that the battery isn't charging after it has started the
engine and during the subsequent running - either because the
alternator/charging circuitry has failed or because something is drawing a
large current so the alternator cannot supply sufficient current both to
supply that load and at the same time replenish the battery charge that has
been taken out during starting.

I'd suggest:

- If you can manage without the car for a day, charge the battery using a
battery charger and then leave it for 24 hours without being connected to
anything: this will eliminate self-discharge.

- If you have an ammeter that can measure large currents, connect it in
series with the battery in the car with a) the ignition and everything else
switched off, b) the ignition on but engine not running. DO NOT LEAVE IT IN
PLACE WHEN YOU START THE ENGINE because the starter motor current will
probably blow the ammeter or fry its leads. If there is a significant spark
when you reconnect the charged battery (without the ammeter) then that
suggests that a large current is being drawn, so maybe it's not wise to use
the ammeter in that case.

- Measure the charging voltage (voltmeter across the battery) when the
engine is idling and when it's revving at 2000 rpm. Certainly in the latter
case you should see around 14V - higher than the voltage without the engine
running.

- Measure the battery voltage with the ignition on but the engine not
running - does this cause the battery voltage to fall below the no-load
voltage of about 12V?

- Get the battery tested at a garage or at Halford's.