Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: Alex W on 27 August 2008, 20:01:14

Title: Very Flat battery
Post by: Alex W on 27 August 2008, 20:01:14
Went to use the car today but the battery was so flat it had trouble opening the doors. The vehicle had been standing for four days.

Charged it up and all OK again - but I need to know what happened so I can stop it happening again.

I have had no sign of any problem with power, no warning lights on the dash or problems starting (since previous posting in July). I do have a faulty central locking motor in the drivers door (and a replacement I am yet to fit).

The battery is about two years old and is a GM battery from the main dealer (£64 at the time). I had a new alternator fitted in March this year when the bearings failed on the old one.

I need to know what steps I should take to try and trace the fault? I haven't got a multimeter but I am prepared to invest in one if required (any recommendations as to which is best for amateur home user).

Thanks in advance for any help offered. :)
Title: Re: Very Flat battery
Post by: TheBoy on 27 August 2008, 20:06:22
Would be good to check battery voltage, with car off, at idle, and at 2.5k rpm...
Title: Re: Very Flat battery
Post by: Alex W on 27 August 2008, 20:22:18
Looks like I need a multimeter. Off to Halfords in the morning then! I might get their big socket set while its on special offer too.
Title: Re: Very Flat battery
Post by: robby30 on 27 August 2008, 20:44:43
Quote
Looks like I need a multimeter. Off to Halfords in the morning then! I might get their big socket set while its on special offer too.

screwfix has a good value multimeter for £10 does most things halfrauds i would guess would be much more
Title: Re: Very Flat battery
Post by: Proz on 27 August 2008, 20:47:45
Quote
Looks like I need a multimeter. Off to Halfords in the morning then! I might get their big socket set while its on special offer too.

I just got the bigger of the two socket sets they have on offer ( £130 ).... dont know about the smaller set but the bigger one has just about everything i could ever use in it ... and if its the Halfords Proffesional one if anything breaks its replaced free  :y
Title: Re: Very Flat battery
Post by: Agemo on 27 August 2008, 21:35:40
I know it's a bit low tech, but are you sure the boot light is going our? One little bulb can sap the battery in four days.
 ::)
Title: Re: Very Flat battery
Post by: Alex W on 28 August 2008, 09:17:12
Checked the boot light, its off. Checked the glovebox too while I was at it, thats off too.
Title: Re: Very Flat battery
Post by: Marks DTM Calib on 28 August 2008, 09:28:05
Disconnect the power sounder....
Title: Re: Very Flat battery
Post by: Elite Pete on 28 August 2008, 10:32:55
Make sure you haven't left the indicator on when you've parked up. This will leave a parking light on
Title: Re: Very Flat battery
Post by: Alex W on 28 August 2008, 19:06:09
Power sounder is only two years old, new one fitted by main dealer when he did the battery.

Voltage Readings

Off Car 12.38
On Car engine off 12.4
Engine Idling 13.45-13.48
Engine at 2500rpm 13.45-13.48
Title: Re: Very Flat battery
Post by: dbug on 28 August 2008, 21:25:40
Looks ok - would expect voltage with engine not running to be 12.5-12.8 volts.  Wouldn't anticipate issues with your readings though!
Title: Re: Very Flat battery
Post by: Alex W on 28 August 2008, 22:15:52
The slightly low voltage at rest is probably because I didn't charge it up for long enough.

I assume that we can rule out a faulty (new) alternator?

If it drains again I will disconnect the power sounder as suggested bit in the meantime has anyone any other ideas?

Title: Re: Very Flat battery
Post by: TheBoy on 29 August 2008, 10:25:47
The voltages look OK.

Heated rear window relay is known to stick sometimes, but doubt thats been on this weather.

Door motors sometimes stick on apparently.

Other than that, interior lights, alarm been sounding, any light left on, just the usual...

Worth unplugging power sounder if it repeats, though yours is fairly new.
Title: Re: Very Flat battery
Post by: Derek_in_Penzance on 29 August 2008, 18:44:24
I don't know if this applies to Omegas, but it might just....

...be the main interior courtesy lamp. On late Monzas, Senator Bs and Carltons the circuitry above the bulbs can fail, drawing a tiny, tiny almost unmeasurable current. Over a period of say 10 days, this can flatten a battery.

It's worth thinking about. The same fault may afflict Omegas. It took me ten years to diagnose this fault on my Monza GSE, and then it only happened by accident.

I recently advised a Senny B owner about this, and it cured his problem of battery going flat in ten days or so, with no apparent reason, and having checked everything under the sun.
Title: Re: Very Flat battery
Post by: Alex W on 29 August 2008, 20:39:39
So, could my faulty driver's door central locking motor be the culprit?

It does the usual, works sometimes, sometimes not. As I said I have a second-hand replacement just haven't got round to fitting it yet. I'll try and swap it this weekend.
Title: Re: Very Flat battery
Post by: shyboy on 30 August 2008, 09:23:32
I would have thought that any electrical component not working spot on would be a prime suspect. Problem is identifying the intermittent failure, so you're back almost to trial and error.
Title: Re: Very Flat battery
Post by: TheBoy on 30 August 2008, 09:51:46
Quote
So, could my faulty driver's door central locking motor be the culprit?

It does the usual, works sometimes, sometimes not. As I said I have a second-hand replacement just haven't got round to fitting it yet. I'll try and swap it this weekend.
Doubt it, yours is the std lazy motor type fault....  ....but worth changing anyway.
Title: Re: Very Flat battery
Post by: willyboy on 31 August 2008, 12:02:25
 >:( Bugger its just happened to me not been out in car for about 4days &batterey flat, barely turned over, so now battery on charge, will have to have it checked as think its a pretty old VX original once I'm up & running must be some virus going about !! ;)
I have a multimeter will try it suppose its just hold the mm/connections against the battery terminals & see exactly what it registers ?
Title: Re: Very Flat battery
Post by: mark readman on 31 August 2008, 20:11:42
It is not un common to leave the ruddy radio radio on by thinking you have switched it off but instead on when the volume is right down, that soon sees off the battery.
very easily done !
Title: Re: Very Flat battery
Post by: davlad22 on 31 August 2008, 22:23:27
If it's a standard VX radio I think they are set to time out and switch off after 1hr  :-/