L322 4.4 Vogue Auto 2005 Battery drain...

Sorry Chaps, I hate to start a new one - but search doesn’t seem to be working at the moment- I’ve read a lot of your advice and experiences, but memory fading.

So Battery low over night - would unlock, but key would not shift more than one click to attempt a start - pretty sure nothing was left on, such as lights, but I have got a 5 year old who likes to press buttons... Called RAC because other car up on stand with a flat tyre, and pointing in wrong direction to be able to effect a jump start without miles of leads... Prior to this had been fine, and just driven about 20 miles before parking for the night. About 16 hours to low battery.

After starting and running for a while RAC measure about 4.5 amps draw with everything off and car locked.

It’s a 900CCA battery about a year old, and Halfrauds measured 870CCA in it

I start pulling fuses and checking - wiper blades was an obvious one, as one was at an absolute angle, so reset electrically and mechanically. I didnt find anything else obvious using a cheap tester that plugs in to the fuse box. Using my fluke DC clamp meter on the negative cable while locked and alarmed, sees readings start at 8A, dropping quickly to 4.5A, then 2.2A. About an hour later its flicking between 1.1A and 0.9A. Red LED on shifter is out, so I assume more or less everything is shut down. Interior, boot and glove box lights all go out. Is the alarm system really drawing this much current?

What readings do anyone else get? Is there anything else that is an obvious suspect? I did read somewhere about a heater/blower resister causing flat batteries - but presumably a larger draw than 1A?

Most recent battery V readings were 12.81V @21:00 hrs, about 20 minutes after parking up, dropping to 12.68V at 12:00 hrs the next day.

Anything longer than overnight I’m disconnecting the battery - which is ok at home, but a bit of a pain in airport parking...

Thanks is advance!

Battery voltage readings look fairly normal.

Chief battery drain causes are the headlamp wipers not parking correctly, the Final Stage Resistor for the heater blower motor and a duff regulator pack in the alternator.

Saw this and wondered if it may be of use

Saint.V8 said:

Chief battery drain causes are the headlamp wipers not parking correctly, the Final Stage Resistor for the heater blower motor and a duff regulator pack in the alternator.

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hi @Saint.V8

may i pick ur brains plse and ask a daft question, when I had a battery drain on my D3 I had to wait 30 x mins to allow it to go into sleep state , thing is if I started to pull fuses it would wake the system back up

is it completely different with the older models plse that by pulling fuses doesn’t affect the testing of the system

apologises once again asking the daft questions

many thks

gary

Saint.V8 said:

Chief battery drain causes are the headlamp wipers not parking correctly, the Final Stage Resistor for the heater blower motor and a duff regulator pack in the alternator.

Click to expand...

I guess number one culprit on that list of 3, would be the diode pack on the alternator.
I would suggest one of the diodes in the alternator charging pack might be passing reverse voltage.
They are supposed to only let one half of a wave (frequency cycle) through, and to stop any reverse voltage.
But a spike can damage one or more.
There could be up to 9 diodes,
6 main diodes, and 3 other diodes for when you have a priority situation, where you need DC to excite the alternator,
But many don't have these last 3 diodes anymore.

vette

uk_vette said:

I guess number one culprit on that list of 3, would be the diode pack on the alternator.
I would suggest one of the diodes in the alternator charging pack might be passing reverse voltage.
They are supposed to only let one half of a wave (frequency cycle) through, and to stop any reverse voltage.
But a spike can damage one or more.
There could be up to 9 diodes,
6 main diodes, and 3 other diodes for when you have a priority situation, where you need DC to excite the alternator,
But many don't have these last 3 diodes anymore.

vette

Click to expand...

If a diode in the alternator has failed, battery drain is normally quite fast, easy to prove by disconnecting the alternator.
Headlamp wipers not parking or the hedgehog would be my bet.

Ref alternator diodes I believe there an easy test with a multimeter

with the engine running , set multimeter to AC volts then put a test probe on each battery terminal

should ideally be zero or under 0.5 Vac

gstuart said:

Ref alternator diodes I believe there an easy test with a multimeter

with the engine running , set multimeter to AC volts then put a test probe on each battery terminal

should ideally be zero or under 0.5 Vac

Click to expand...

Not sure that will work, it will depend on the battery among other things, there is always an AC component present that is damped by the battery. Can be seen on a scope.

Datatek said:

Not sure that will work, it will depend on the battery among other things, there is always an AC component present that is damped by the battery. Can be seen on a scope.

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that’s very interesting ref type of battery

was told this a while back ref the diode test, also remember u mentioning regarding a rectifier that needs a scope

plus know ur extremely knowledgable when it comes to electronics

gstuart said:

hi @Saint.V8

may i pick ur brains plse and ask a daft question, when I had a battery drain on my D3 I had to wait 30 x mins to allow it to go into sleep state , thing is if I started to pull fuses it would wake the system back up

is it completely different with the older models plse that by pulling fuses doesn’t affect the testing of the system

apologises once again asking the daft questions

many thks

gary

Click to expand...

'tis the same on the L322...pull fuses and it can wake the car back up again meaning you have to pull the fuse, wait for the vehicle to sleep again....and when you put the fuse back, this can also waken the car!!

Obviously it depends on which fuse is pulled as to if it wakes the car, as some will and some won't....

Saint.V8 said:

'tis the same on the L322...pull fuses and it can wake the car back up again meaning you have to pull the fuse, wait for the vehicle to sleep again....and when you put the fuse back, this can also waken the car!!

Obviously it depends on which fuse is pulled as to if it wakes the car, as some will and some won't....

Click to expand...

bless u , indeed ref the fuses , think there’s 26 x ecu’s in mine so dread to think how many there are in the L322

know when I had a residual battery drain on mine I found it easier to make up some test leads

plus at least with the normal fuses could use a multimeter across the test points on the back of the fuses , to see if there was any residual current going across them, or use a clamp meter

also found it easier taping a pair of test leads so could test the smaller cabin fuse box which is tucked up behind the glove box

plus I got a half decent clamp meter which made life easier

me being a sad old git found it quite therapeutic

gstuart said:

bless u , indeed ref the fuses , think there’s 26 x ecu’s in mine so dread to think how many there are in the L322

know when I had a residual battery drain on mine I found it easier to make up some test leads

plus at least with the normal fuses could use a multimeter across the test points on the back of the fuses , to see if there was any residual current going across them, or use a clamp meter

also found it easier taping a pair of test leads so could test the smaller cabin fuse box which is tucked up behind the glove box

plus I got a half decent clamp meter which made life easier

me being a sad old git found it quite therapeutic

View attachment 198194 View attachment 198195

View attachment 198196

Click to expand...

Now thats 'out of the box' thinking....

Saint.V8 said:

Now thats 'out of the box' thinking....

Click to expand...

u like that then, think u have to get creative sometimes , lol

Got to trace a battery drain I’ve currently got , think it’s the split charge T max solenoid stuck open as I’ve got a 150 Ma drain and should be under 22Ma, wondering if the smaller aux battery is draining the main battery , just fitted a new 019 main battery

The red uni T clamp meter in the pic won’t zero so had to order a new one ,

Ordered one of these
https://uk.trotec.com/fileadmin/downloads/Messgeraete/Elektrizitaet/BE44/TRT-BA-BE44-TC-001-EN.pdf

Thanks everyone - as always impressed by the knowledge and helpfulness of you all - I have got a spare FSR, and Ill check the alternator next - fuse pulling didnt show anything much - Will keep you updated if/when I strike gold - clearly I have a long way to achieve anything close to 30mA

WightinNL said:

Thanks everyone - as always impressed by the knowledge and helpfulness of you all - I have got a spare FSR, and Ill check the alternator next - fuse pulling didnt show anything much - Will keep you updated if/when I strike gold - clearly I have a long way to achieve anything close to 30mA

Click to expand...

hiya

indeed ur find extremely knowledgeable and helpful people here

looking at the chart I think urs should be under 16-18 Ma

Not my place to but in (because I have no true credentials) but.... A very low range Voltmeter like this one would let you measure the volt drop across the fuses and therefore perhaps the current draw from that circuit without waking the car up at all?
This chart is meant to be a reflection of the likely parasitic drain. As @Datatek has previously said, most DVM's are not sensitive enough. The one in the link IS (I think).