On 08/05/2018 16:07, Graeme wrote:
In message , Bob Minchin
writes
Nowhere in the question does the op say
"If he has disconnected te battery entirely and put a meter in the
circuit and no current is flowing, then no current is flowing and the
battery cannot be discharging *via any external means*. "

Just to be clear, if I park the car for a couple of days, with the
battery connected, the battery goes almost flat, but left 4 1/2 days
with the battery disconnected (earth lead removed from battery
terminal), the battery remains fully charged.

This morning, battery fully charged, I put an ammeter between the
battery terminal and earth lead.Â* No movement.Â* Repeating, with a door
open and courtesy light therefore in circuit, then I can see the ammeter
needle move.Â* Not much, but enough to know it is working.Â* Ammeter is a
standard car 2 inch circular 30-0-30.

Repeated but with a small 12v MES bulb between the battery terminal and
earth lead.Â* No light until door opened.


Just a thought....
If you have a voltmeter of some sort - connect it across the 12v mes
bulb in the above setup.
Naturally, there'll be a voltage drop across the bulb when the door is
opened, but is there any volt-drop across the bulb when the door is
closed..? If there is, that indicates that there's a small current
'leaking' through the interior light, via the door-switch.
Car batteries are designed to provide lots of current for a short period
of time, to start the engine. They're not good at long-term supply of
smallish currents... - and the car ammeter won't indicate accurately
down at that level...

Come to that - can you put a test meter across the in-car ammeter?
With everything off there should be no voltage. A sensitive voltmeter
will tell you if there's a small current being drawn from the battery,
even when everything on the car is 'officially' off..