<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=UTF-8" http-equiv=content-type>
<META name=GENERATOR content="MSHTML 8.00.6001.23588">
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff text=#000000>
<DIV><FONT size=2>That's a significant drain, even with alarm, radio and clock
it should last for 2-3 weeks.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Your battery voltage off-car seems OK, but that is not a good
indication of the amount of charge i.e. cranking power. If you put it back
on the car after three days and it cranked OK that does indicate the battery
itself is OK - up to a point.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>However the Lucas Fault Diagnosis Manual states that if a
battery becomes 25% discharged then the on-board charging systems will never get
it back to full capacity, and if it has become completely discharged they will
never put back more than 50% capacity. For that reason a flattened battery
has to be boost charged for a period to restore full capacity. Using a
conventional charger this means charging at 16-17v for a couple of hours in a
well ventilated space. Or you can use one of the more sophisticated
'maintenance' chargers but only if they have a 'recovery' program, and not all
do. These charge using pulses of up to 20v.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>But back to the drain. If you have an analogue meter
switch to its 12v i.e. VOLTS range and connect it in place of the battery earth
lead. With no drains on a car with an alternator you should see a few
volts registered. If it shows 12v there is a drain. In that case the
first thing to do is unplug the alternator, and if the drain drops to zero that
is the culprit. With the few volts registered unplugging the alternator
should also drop it to zero. But if still at 12v </FONT><FONT
size=2>start disconnecting things like your radio, the purple circuit fuse,
remove browns from things like the ignition switch, lighting switch, starter
relay, hazard fuse and so on, looking at the meter each time. If still
there remove the browns from the starter solenoid, and finally the battery cable
from the solenoid, but normally it will have been discovered by
now.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>You can also do this with a digital meter but they are far
more sensitive and will show 12v even with just the normal alternator leakage,
and may not fully drop to zero with that disconnected if there is dampness
anywhere.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>PaulH.</FONT></DIV>
<BLOCKQUOTE
style="BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV><FONT
size=-1><FONT face=Arial><BR>After leaving my MGB GT V8 for a few days - maybe
4 or 5 I find the battery is completely flat. Did that 3
times. So I took the battery out, charged it and waited 3 days.
The voltage dropped from 13.15V on Sunday 3pm to 12.91V 3pm Wednesday which
does not seem to indicate that it is the battery's
problem?</FONT></FONT></BLOCKQUOTE></BODY></HTML>