Battery drain

[endorfin]

From when I first got my 2.5 TD XM, on starting the car there always felt like there was just enough battery power left to start the car if you know what I mean. It would turn over and you could see the battery weakening then it would fire. Drive it all day and same thing would happen the next day on starting. I put this down to the battery and bought a brand new Bosch with 760 CC amps. It seemed to cure the problem the first few starts but after that its gone the same way as the previous battery. It has just enough power for a single start.

Now that the car has been standing a couple of weeks now, I went to start it today in case ATS want to pick it up tomorrow (see other thread) and it wouldn't start at all. Battery is far too weak to start.

Obviously something is draining the battery while its standing. Anyone had anything similar happen to theirs and did they find out the cause?

[noz]

Hi endorfin,

A couple of pointers:

The cigar lighters stay live with the ignition off on an XM. Anything plugged in permanently (speed trap detector, sat nav etc) will continue to be powered even when you leave the car and lock it.

The boot light can stay on if the trigger switch next to the latch is jammed.

The quality of the battery terminals in an XM is very poor. I cut mine off, soldered the multistrand cables and fitted new clamped ends.

The earth cables running from the battery negative terminal to the body can corrode particularly where they fix to the inner wing. It would do do harm to take these off one by one and clean with emery cloth and reassemble with copperslip.

The earth cable from the engine to the battery negative terminal can corrode at the bellhousing end. Again cleaning with emery cloth might help.

My 2.5TD suffers from a lazy starter solenoid. I've had the starter off and cleaned all the contacts and connections. However, the solenoid itself is a sealed unit and cant be accessed to clean the heavy current contacts inside. As a result mine can click a few times in the morning before the switch finally makes and starts the motor.

The passenger sun visor has a light built into it. Sitting here I cant remember how its activated. Might be worth a look.

The trick would be to physically measure the charging current and voltage across the batery terminal joints. A bad joint between the cables and clamp or clamp and battery terminal may either hamper charging or hamper starting current for the starter motor.

I hope that gives you some food for thought.

cheers

noz