The surest way of checking for battery drain is to connect a hand held multimeter, set to an amps reading. The multi meter must be connected IN SERIES between the negative terminal of the battery the removed earth strap from the battery to the body.

In English, disconnect the negative strap on the battery, set the multi meter to read amps, connect the black lead of the amps meter to the battery post and the red lead of the amp meter to the disconnected strap.

If you get a negative amps reading swop the leads connecting to the battery and disconnected lead.

With all doors shut, ignition off and the bonnet push button switch, if fitted, held down. Take a reading on the amp meter. This should have a reading of approximately 0.5amps - 0.7 amps.

Keep taking your reading for about one minute. The first 30 seconds or so may have a much higher reading due to the fact the internal light would take about 30 sec. - 40 sec. to go out, when this happens the reading should drop. Any higher reading over about 0.7 amps indicates you have some thing consuming battery current. This additional consumption has to be located and rectified.

The sort of consumables could be the boot light remaing on, even though the boot lid may be shut. To eleminate this from the equation, remove the bulb to the boot compartment and read you amp meter again, if there is no change to a high reading then you need to search else where.

Repeat the same exercise to eliminate the glove box bulb, the door switches individually, but in this case disconnecting the door switch. Carrying on, check readings with the alarm armed or disarmed, switch off the radio. Identify the fuses and disconnect each fuse to the electric windows to see for any difference, check the clock fuse by disconnection and checking on current draw. Consider the alternator in your tests, by disconnecting the battery feed lead to the alternator, infact even the block connector to it also. That is the general idea.

Remember to reset the amp meter after use, current can only be measured with the multi meter connected in series to the electrical circuit. It is measuring volts that the meter is connected in parallel. Take head as the meter can be damaged if not properly connected!