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[Koomorph]

Gents, I've not been on here for a while as my dad's omega has been thankfully trouble free. 

Quick questions though, it has since last week developed a fault where the battery is draining overnight. Car won't start in the morning... but if he disconnects the battery overnight, and reconnects in the morning, it starts the car fine.

I'm seeing him this weekend and looking to do a parasitic drain test to see if we can find the fault. The powersounder has been removed about 3 years ago.... Are there any other common electrical drains/faults which we should consider as first port of call? I've read about the boot light being an obvious one. Accessory relay also...(not sure which this is without seeing the car)? Anything else you can recommend?

Cheers as always! 

[Shackeng]

Best thing if you can't see anything obvious, is, using your test meter, check how much current drain is with everything off, then pull each fuse in turn to find the culprit.

[Koomorph]

Yeh, that's the plan, was just wondering if there is anything else common I should look outfor beyond the boot light. 

[omega2018]

drain after 15 mins should settle to 60-80mA apparently.  if not start with the big fuses in the engine bay especially fuse FV5 next to the rightmost fuse, FV6.  if pulling FV5 stops the drain put it back and start pulling F1, F6, F7, F10, F20, F25, F27, F35 in the cabin.  esp F7.   also check the relays in the cabin.  could be the regulator on the alternator on its way out- replacing  that seemed to fix my drain.  good luck.

[biggriffin]

Common drain is glove box light also is battery old,and just not man enough to hold whilst connected.

[Koomorph]

Thanks everyone, will give it a good going over this weekend and report back.

[Kevin Wood]

Might be worth starting by removing the power sounder. They can drain excessively when knackered, and have been known to start a fire.

Consumer delay relay is another possibility, although I doubt that would drain it overnight.

As said, pull the fuses one by one while monitoring current to try to narrow down the faulty circuit.

Sometimes this can be down to a rectifier in the alternator going leaky, so if the pulling of fuses doesn't help, bear this in mind.

[Koomorph]

Thanks Kevin - the Powersounder was removed a few years back. Really hoping it's just a boot or glove box light!

[omega2018]

if it is the regulator much better to know now than when you are driving along and it fails completely - you will need recovery. i think FV5 might isolate the alternator but could be wrong. that was the fuse that my drain was going through shortly before the regulator failed completely. i suppose my drain could still be there but not noticed it. i ought to check.

[Bigron]

Hitching a ride on this topic, I know my quiescent drain is a bit high and seem to recall a comprehensive chart being posted on here some time back; does anyone have a link, please?
Unrelated, but of concern to me, I tick the "Notify" box for topics of interest but no longer get notifications - any clues, gents?

Ron.

[BazaJT]

Can the bonnet switch not also cause this kind of issue?

[Koomorph]

So an update to this.... saw my dad and tried to do a drain test... which was somewhat inconclusive - (with the multimeter in series) the drain was very erratic...(jumping from 0.25A to 4.2A) ... becasue... the interior light was going on and off and what sounded like the door solenoids clicking on and off continually every 5 seconds or so.... no stable reading and no idea why the light and (door??) solenoids were clicking... really odd. With the multimeter removed and the battery terminals reconnedted as normal, there was no erratic behavior from the interior electrics.

However, I think the problem may be something else, as he said that the battery warning light on the dash has now started coming on occasionally when driving.... 

I tested the battery voltage/charge with the car running when at idle and it only showed 12.6v.... dropping over a period of 30seconds to just over 12v. After applying 2K rpm, it rose to 13.2V.... and then slowly kept dropping even at constant rpm. The battery light on the dash would go off.... then on again.... then off when more revs applied....

So it seems like an alternator issue? OR would this be caused by the regulator?
And if either of these.... can I source an inexpensive one for him? Is the regulator a big job/how-to available?
Thanks as always gents!

[Bigron]

It does sound like an alternator problem, but it's worth going to one of the larger battery places - even Kwik-Fit - for a free battery and alternator check.
Your erratic behaviour with the meter connected could be due to the internal resistance of the meter, especially if it was on a range lower than the 10A/20A range, upsetting the electroncs.

Ron.

[Koomorph]

I'm sure the battery is fine (18months old), as it takes charge over night when removed and charged, and starts the car no problem.... then when disconnected from the negative, it does start the car the next day also.

Reading were taken at 10A... never went down to the 200m scale.... although it's a cheap meter that could be causing issues I guess.

Battery light on the dash and low voltage (12.6v... and dropping) when car is running at idle across the terminals makes me think it's the alternator.... ?

[Kevin Wood]

Do check the crimping of the connections into the battery terminals. These can often cause low and fluctuating charging voltage as the crimps become loose. A good sign of problems is if the battery terminals get hot when running.

Failing that, yes, I'd say the alternator has issues, but try charging the battery overnight on a mains powered charger before retesting, as a flat battery can also drag the voltage down (although the battery light is also a sign of alternator issues, TBH).