Flat Battery every morning

kingpleb · Post by **kingpleb** » Sun Dec 16, 2007 1:55 pm

Every morning i get up and my Xantia has a flat battery and struggles to start but i think the battery itself is fine but is being drained over night. I cant see lights that stay on and was wondering if there is a way to test the system as th only way i could think of was to remove the fuses one by one to find out what could be causing it. It did seem to coincide with my problem on the dirvers door lock that wont lock or unlock on the remote fob but does work via the key itself.

Any ideas would be appreciated.

Clogzz · Post by **Clogzz** » Sun Dec 16, 2007 3:10 pm

Tune the radio’s long wave to between two stations, volume up, and take the central locking fuse in and out a few times, as it will cause the radio to crackle if current passes there.
You may also see a spark at the fuse.

Any other unknown places, same with an external radio, but making and breaking contact at a battery terminal.
There should be no spark at the terminal, unless something draws a fair bit of current.
If you have a multimeter, you can check for voltage drop when connecting the battery.
The small permanent radio memory and clock current won’t cause any drop.

It takes a fair bit of current to flatten a diesel battery overnight, and you may even find a ‘warm’ fuse or wire.

Baldbazza · Post by **Baldbazza** » Sun Dec 16, 2007 5:00 pm

I had this problem (either on the Xantia or XM - I owned both some time ago & can't remember which

).

It was caused by the boot light switch, which was a pokey-out thing on the left-hand side of the hatch. It was supposed to be pushed in against a foam pad when the hatch was closed, switching off the power. But the pad had moved slightly, the switch just missed it so didn't get pushed in - the boot light stayed on overnight. Hence flat battery every morning.

Might be worth a check?

AndersDK · Post by **AndersDK** » Mon Dec 17, 2007 10:19 am

What makes you sure the battery is still operational ?

The fact that the battery has enough energy to crank the engine - but does so reluctantly - tells me that you most likely have problems excatly with the battery.

First check is to remove the battery clamps, rub clean the poles and the inner surfaces of the clamps. Then make sure the clamps are a tight fit - but NOT torqued, as this will fracture them.!

Next check is to check the battery voltage first thing in the morning, before you do anything else to the car. The voltage should read at least 12.6Volts indicating a charged and working battery. A somewhat lower voltage (closr down to 12.0Volts) tells you the battery is tired.
A considerably lower voltage like below 11 volts means the battery is well and truly shot. One of the cells have collapsed.

kingpleb · Post by **kingpleb** » Mon Dec 17, 2007 11:22 am

Ill check the fuses and the bootlight thaks for that one

The main thing is that even if its left for a few hours during the day it will restart even with a cold engine(ie the temp needle stays at the bottom of the guage) but only has problems when left overnight

AndersDK · Post by **AndersDK** » Mon Dec 17, 2007 12:31 pm

kingpleb wrote:Ill check the fuses and the bootlight thaks for that one

The main thing is that even if its left for a few hours during the day it will restart even with a cold engine(ie the temp needle stays at the bottom of the guage) but only has problems when left overnight

Exactly the symptoms of a tired battery.

If the battery was empty-flat because of discharging over night by any smaller load - there would not be power left to crank the engine at all. You would only get a "click" and then all lamps would fade out.

The battery wil always fall back to a dormant state from the charging alternator during engine run. This dormant state is reached some 1-2 hrs after the charging seizes. In this state the battery reaches a voltage of 12.8V indicating a fully charged and working battery.
During charging when engine is running, the battery quickly rises to and remains at approx 13.8-14.0V.
This is the completely normal electrochemical behaviour of a lead-acid battery.

If the battery is shot, it will typically lose one cell, which then decreases the operational voltage in the dormant state to 10.6V, which is just barely enough to crank the starter motor & cold engine. Thats what you see in the morning : a reluctant start.

Check the battery pole voltage - saturday or sunday morning, when you are not too busy. I'll bet a pint the voltage is too low

kingpleb · Post by **kingpleb** » Mon Dec 17, 2007 12:53 pm

Dam, Guess as well as the MOT, the new tyre i need as well for that i have to fork out for a battery and bin the two i have or use an overnight charger to keep it topped up overnight when i need it and then park it on a slope during the day incase it fails again

Way2go · Post by **Way2go** » Mon Dec 17, 2007 4:14 pm

kingpleb wrote:incase it fails again

The advice re battery is good as this is indeed typical of one at the end of its life.
In this state you can be sure it will fail again and on increasing occasions.
Even if it runs, with shorted cells, you are increasing the load on the alternator risking failure and further expense!
Best to spend now on a battery, to save unnecessary expense later!

ellevie · Post by **ellevie** » Mon Dec 17, 2007 5:02 pm

Why not simply disconnect one of the battery leads overnight, immediately after it has had a good charge.
If it starts normally when you reconnect in the morning then you'll know that your suspicion is correct.

kingpleb · Post by **kingpleb** » Mon Dec 17, 2007 7:15 pm

Ill give the battery lead thing a try tomorrow once ive given it a charge after jumping it again and see what happens as luckily i have another slave battery that i know is fubar but can supply a few volts to keep the radio memory and the alarm going as well