Omega Owners Forum

Omega Help Area => Omega Electrical and Audio Help => Topic started by: 05omegav6 on 09 September 2015, 20:55:38

Title: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 09 September 2015, 20:55:38
Alternator working as it should.
Battery charging as it should.

Plod wiring pulling 0.15A, drops to 0 with ground disconnected. Totally isolated from rest of car.

Feed to main fuse box at battery draws 0.75A upon ignition switch off, dropping to 0.55A after 5 minutes, then finally settling at 0.4A.

Pulling fuses FV5 and FV6 kills this draw dead.

Pulling all the cabin fuses one by one makes absolutely no difference. Likewise the accessible relays next door.

There is a 12v socket connected to the switched live behind the cabin fuses, but this is discounted as it is downstream of the relevant fuse.

The only unfused feeds from FV5 go to the Immobiliser and Alarm. Alarm irrelevant as plod never had one.

The only unfused feeds from FV6 go to the Indicators, the Headlight Switch, Heated Rear Window and Autobox. Autobox irrelevant as car is manual.

Is it feasible that this current drain is down to the light switch :-\
Title: Re: 0.4 Amp current drain killing battery.
Post by: Broomies Mate on 09 September 2015, 21:13:12
Might sound obvious, but remove the light switch and see what happens?  :-\
Title: Re: 0.4 Amp current drain killing battery.
Post by: tidla on 09 September 2015, 21:31:36
Does the heated window have a relay? (im guessing so)
Title: Re: 0.4 Amp current drain killing battery.
Post by: zirk on 09 September 2015, 22:14:29
If its plod, pull the fuse, if it goes through one, for the boot release, may have instant open relay fitted, which sticks, had something simular before on this.

Is it 3.0 or 3.2, if 3.0 relay is behind headlight switch, as it became a standard Plod Mod, if 3.2 could be anywhere but most where in relay box in Engine Bay.
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 10 September 2015, 06:21:14
3.2 but estate, not saloon :y
Title: Re: 0.4 Amp current drain killing battery.
Post by: zirk on 10 September 2015, 17:37:55
3.2 but estate, not saloon :y
Wont be that then.  ;D
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 10 September 2015, 18:48:11
Battery struggled to start the car half an hour after recovery this morning. Turned over but failed to fire, putting the immobiliser light on. Second go saw it start.

Currently tempted to chop it up where it sits :-\
Title: Re: 0.4 Amp current drain killing battery.
Post by: Entwood on 10 September 2015, 18:55:35
Battery struggled to start the car half an hour after recovery this morning. Turned over but failed to fire, putting the immobiliser light on. Second go saw it start.

Currently tempted to chop it up where it sits :-\

Can I have first dibs on ABS/TC bits .....   ;) ;) as well as air con compressor ...  ;) ;) ;)

I know .. fruitless request .. you'll mend it soon enough .. :)
Title: Re: 0.4 Amp current drain killing battery.
Post by: 2nddaniel on 11 September 2015, 20:48:08
Quote
Feed to main fuse box at battery draws 0.75A upon ignition switch off, dropping to 0.55A after 5 minutes, then finally settling at 0.4A.
Battery struggled to start the car half an hour after recovery this morning. Turned over but failed to fire, putting the immobiliser light on. Second go saw it start.

I had the same trouble, ended up measuring load, and eventually decided the altenator was faulty, that it wasn't charging.
I was wrong.
I had the alty tested, and was told it was very healthy.
It's an intelligent altenator (like on a BMW) only charging the battery when required.
I replaced my battery and all my troubles were gone. I got the biggest bastard that would fit, 75Ah with 700 cold cranking amps.

If you aren't convinced that your battery is faulty (i am though), consider the following calculation:
Assuming a 60AH (60 amps for an hour) battery with a 0.35amp drain (my measurements);
60/0.35= 150.
That's 150 hours, the battery should run that piddling little load for over 6 days.

Itls only surface charging mate. The altenator is seeing a healthy voltage at the battery terminals and stopping charging, the battery is just weak.

My old battery was only 4 years old.

These hi spec omegas have a lot of kit that runs on after the engine switches off. I found 3 fans under the bonnet, - that coupled with alarm current, interior light timers, immobiliser timers, and that sort of thing was killing my old battery within 10 mins after a long journey. I was expecting the battery to be getting a right old boiling, but it weren't, just a surface charge - cos it was knackered.

You can prove the battery is bad yourself, like this:
Charge it for a few days, maybe over the weekend, On Monday it'll seem like a new car, by the end of the week it'll be struggling to start.

A bit of a long spiel, i know. I hope it's useful though.
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 11 September 2015, 21:08:17
That makes sense :y

Need a new battery for tother one anyways so I can get one for both cars. Will the TD battery fit?
Title: Re: 0.4 Amp current drain killing battery.
Post by: Nick W on 11 September 2015, 21:14:07
You should  consider buying a battery tester. A tool you won't use much(unlike mine), but is handy to have. Cheap too.
Title: Re: 0.4 Amp current drain killing battery.
Post by: 2nddaniel on 11 September 2015, 21:22:26
TD ? Turbo Diesel?
I don't know if it will fit.
I took my old battery off, noted that it filled the battery tray, took it to Digby and Sons in Heywood (who, by the way, bench tested my altenator for free -AND told the truth - not pretending it was faulty and charging for a new one), and asked for the biggest capacity battery they could source that was the same physical size as that old one.
And they did.
£90 plus vat.
Fitted. (the following day).
 :)
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 11 September 2015, 21:33:45
You should  consider buying a battery tester. A tool you won't use much(unlike mine), but is handy to have. Cheap too.
AA battery tester initially said 'Recharge then retest' followed by 'Charge fully' on the second test, suggesting it simply needed a decent charge.

My charger quickly changes from Charging to Charged when connected, implying that it charges in the same manner as the alternator... :-\

Alternator looks to behaving as expected according to Kevins guide, which further points to a dead battery.
Title: Re: 0.4 Amp current drain killing battery.
Post by: Bigron on 11 September 2015, 23:45:12
The battery has gon low capacity, hence the short time to apparent full charge - is it sulphated up? Not much you can do about it if it is, but when the plates are coated with lead sulphate due to abuse or old age, you aren't using much of their active area.
A quick check would be to charge it fully - to gas point if you can see the electrolyte - and then use a known current load (headlamp bulb, 60watt, approx 5 amps) and time it to extinction.
With a healthy, full capacity battery your bulb should stay lit for at least 10 hours. Any less and it has proportionately less effective capacity.

Ron.
Title: Re: 0.4 Amp current drain killing battery.
Post by: Kevin Wood on 12 September 2015, 08:54:06
Notwithstanding the condition of the battery, if you still have a 400mA load when off, the battery will go flat in short order.
Title: Re: 0.4 Amp current drain killing battery.
Post by: TheBoy on 12 September 2015, 09:25:38
As Kevin Wood implies, 0.4A idle discharge is very high.  Mine are in the order of a few 10s of mA, once the consumer timer has turned off.

Sounds like the battery is shagged TBH, but that may be a symptom of the drain issue.
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 12 September 2015, 11:37:42
If a new battery allows the car to function acceptably for a couple of weeks or so, then I can live with that tbh...
Title: Re: 0.4 Amp current drain killing battery.
Post by: 2nddaniel on 15 September 2015, 01:06:44
I tend to think 0.4A isn't very high at all.
A 5watt load connected to a 12volt battery consumes 0.4amp, or 400mA. A security alarm on a car would fit that description. Hell, a household security alarm runs 350mA without any PIRs or battery charging -for comparison.
 
Title: Re: 0.4 Amp current drain killing battery.
Post by: omega2018 on 15 September 2015, 02:26:24
agreed 400ma isn't high however the load when quiet and settled down should be 60-80ma.  even at 0.08 amps (80ma) draw, a 66a/h battery would be completely flat in 1 month
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 15 September 2015, 05:35:22
Ok, so the conclusion is that the battery is indeed Donald, a situation not helped by the current drain, rather than the current drain flattening a good battery in short order...
Title: Re: 0.4 Amp current drain killing battery.
Post by: Kevin Wood on 15 September 2015, 09:33:08
I tend to think 0.4A isn't very high at all.
A 5watt load connected to a 12volt battery consumes 0.4amp, or 400mA. A security alarm on a car would fit that description. Hell, a household security alarm runs 350mA without any PIRs or battery charging -for comparison.

Yes, but it runs from the mains, so power consumption is not critical. A car's consumption should be under 100 mA.

A 400 mA load will completely flatten a 65 Ah battery in good condition in less than a week, so it's an unacceptable level of drain.
Title: Re: 0.4 Amp current drain killing battery.
Post by: omega2018 on 16 September 2015, 23:52:34
double check the altternator i recall that before my regulator failed completely i had a drain that was only cured by removing fv5.  the alternator was charging but a bit low.  after replacing the regulator the drain has gone.
Title: Re: 0.4 Amp current drain killing battery.
Post by: 05omegav6 on 17 September 2015, 20:24:04
Have dropped a new battery in, and pulled fuses 5 and 6... also acquired a new multimeter, as last one hasn't worked since a gravity induced conversation with the drive :-[, so will follow Kevins guide and systematically go through the thing :y