Omega Owners Forum

Omega Help Area => Omega Electrical and Audio Help => Topic started by: scottambrose on 23 October 2012, 10:41:02

Title: battery going flat
Post by: scottambrose on 23 October 2012, 10:41:02
thought it was my stereo which was turning itself on in the night but ive disconnected that aswell as the power sounder and the boot light. and still i keep getting a flat battery every few weeks. ive changed the battery for 3 different types. and all tested good each time, are there any other common drains on the omega it could b? :(
Title: Re: battery going flat
Post by: Raymienets on 23 October 2012, 11:06:38
What about the Alternator have you had that checked?
Title: Re: battery going flat
Post by: pauls on 23 October 2012, 11:22:24
This is a long shot but my old cdx had a battery drain on the sun visor :y
Title: Re: battery going flat
Post by: scottambrose on 23 October 2012, 11:58:18
how am i going to be able to tell whats draining. its fine for a few weeks then its flat when i go to start in the morning. the alternator is charging ok :-\
Title: Re: battery going flat
Post by: Martian on 23 October 2012, 12:22:25
how am i going to be able to tell whats draining.
Put an ammeter in series with the battery and start pulling fuses one by one.
Title: Re: battery going flat
Post by: scottambrose on 23 October 2012, 14:57:18
so i put the ameter in series and in theory i pull each fuse one by one until the meter reading drops. what should it drop to? and is there anything i cant test when the cars unlocked. ie alarm drain
Title: Re: battery going flat
Post by: Kevin Wood on 23 October 2012, 16:18:52
Alarm drain doesn't change much whether unlocked or locked. Open the bonnet, shut all doors, fit ammeter in series with battery, then leave the car for 15 minutes or so for the consumer delay to expire. It should settle to 60-80mA.
Title: Re: battery going flat
Post by: scottambrose on 23 October 2012, 17:54:56
i dont have a meter at present so did it with the 5 watt bulb trick and the bulb lit really brightly but went out when i removed the middle 80amp fuse from the box that sits on top of the battery. theres from left to right 1 80 amp a space then a green fuse then 3 more 80amps and i removed the middle one and the bulb went out.

then with it back in the removed every fuse from the fuse box under the steering wheel and only fuse 7 at the bottom right made a difference. any ideas?
Title: Re: battery going flat
Post by: Martian on 23 October 2012, 22:38:18
Is there not an emblem on the fuse box cover showing what circuits are covered by what fuses?
Title: Re: battery going flat
Post by: Kevin Wood on 23 October 2012, 23:12:04
F7 feeds the accessories connected to the consumer delay relay as far as I can see. Did you wait a good while to see if this went off?

I'm wondering if the timer circuit would have worked properly with the resistance of a 5w bulb in series with the supply, TBH. :-\

Worth taking F7 out, and see if it discharges. You'll probably lose interior lights, etc.
Title: Re: battery going flat
Post by: Dave DND on 23 October 2012, 23:14:41
Try a different battery -  Could be the plates are on their way out ?

 :-\
Title: Re: battery going flat
Post by: scottambrose on 24 October 2012, 08:19:04
this is the 3rd battery in a few months. the interior lights and windows etc all still worked with f7 removed. all it did was click alot when i removed the fuse and the bulb then started pulsing
Title: Re: battery going flat
Post by: Kevin Wood on 24 October 2012, 09:52:38
Hmm. I think you need a proper ammeter on it, TBH.
Title: Re: battery going flat
Post by: scottambrose on 24 October 2012, 11:09:40
Will sticking the ameter in the fuse slot work to show me the current draw
Title: Re: battery going flat
Post by: Martian on 24 October 2012, 12:01:42
Will sticking the ameter in the fuse slot work to show me the current draw
Yes, but it won't pin down the individual component that is causing it.
Title: Re: battery going flat
Post by: scottambrose on 24 October 2012, 13:31:02
so say i find its fuse 7 which is interior lights etc according to the book. do i then take each bulb out and put the ameter in each one to see which is drawing current
Title: Re: battery going flat
Post by: allen25 on 24 October 2012, 13:59:46
If you have been through the system and have found an offending circuit, do post up the results because almost certainly someone here will have seen it before.
Title: Re: battery going flat
Post by: Martian on 24 October 2012, 20:18:02
so say i find its fuse 7 which is interior lights etc according to the book. do i then take each bulb out and put the ameter in each one to see which is drawing current
If the lamp is drawing current then it will be lit, although I'm now thinking (based on your choice of words) that the boot lamp switch could well be faulty and keeping the boot lamp illuminated even when the boot (or tailgate) is closed.
Although it's only a 5W load, that (combined with the normal quiescent drain you would expect) would be enough to drain the battery enough for it to notice if you don't use the car for a couple of days.

As far as the ammeter goes, you leave that in position of the fuse and you simply disconnect the devices on that circuit (eg, clock, radio, etc) until the current drain drops back to the expected norm.
When the current drain returns to normal, you have found the offending item.
Title: Re: battery going flat
Post by: Entwood on 24 October 2012, 20:33:41
for the sake of a few quid it is well worth having one of these in your toolbox .... makes circuit checking a doddle .. they do different sizes for normal spades and micro-spades ...

http://www.ebay.co.uk/itm/Automotive-Current-Tester-STANDARD-Car-Fuse-Boxe-Test-/260597798106?pt=UK_Sound_Vision_Other&hash=item3cacd6d4da

hth :)
Title: Re: battery going flat
Post by: scottambrose on 25 October 2012, 08:09:06
i pulled the rear seat down with the car locked and boot shut and the boot light was off. unless its coming on intermitantly. as when i checked last night i had no current draw from fuse 7.
Title: Re: battery going flat
Post by: scottambrose on 25 October 2012, 13:05:06
fuse 7 is drawing 26.2 on my multimeter whereas all the others in the bottom row are reading 0. is that about right?
Title: Re: battery going flat
Post by: scottambrose on 25 October 2012, 15:11:50
when i plug the meter into the cig light fuse, it reads 0 until i turn the key then it reads the same as fuse 7.
all i can see that stops working when fuse 7 is pulled is the kerb lights. is there anything else on fuse 7's circuit, and should fuse 7 have a permanant current even when the cars been asleep for over an hour
Title: Re: battery going flat
Post by: scottambrose on 26 October 2012, 08:27:25
sorry to keep asking fuse 12 is also drawing 25 and fuse 20 is drawing .4. ive left fuse 7 disconnected but cant disconnect 12 as the info display and climate control doesnt work, what else does 20 use.
Title: Re: battery going flat
Post by: Kevin Wood on 26 October 2012, 11:57:08
Can you include the units in your current measurements? 25A is a shedload, 0.4A is significant, 25mA is not a problem and 0.4mA is nothing at all for practical purposes. ;)
Title: Re: battery going flat
Post by: scottambrose on 26 October 2012, 12:08:06
http://www.toolstation.com/images/library/stock/webbig/98689.jpg?rand=576444555

this is the multi meter and ive set it to the 200 on the right hand side next to the v
Title: Re: battery going flat
Post by: Dave DND on 26 October 2012, 15:36:40
I don`t like to be the bearer of bad news, but I doubt very much if that multimeter is going to be sensitive enough, nor adequate to start tracing miniscule current drain amounts. Great for general purpose voltage work, but you really ought to be looking at a clamp meter if trying to trace current drain.

 :'(
Title: Re: battery going flat
Post by: Kevin Wood on 27 October 2012, 02:16:50
You've got to spend significant money on a clamp meter to look at currents this small without it drifting all over the place, though. (let's face it, you can't get any DC clamp meter worth having for less than £60-75). Not worth it to fix one fault.

That meter will do the job but you need to know what range you're on and how to interpret the readings. :-\
Title: Re: battery going flat
Post by: opelman on 27 October 2012, 07:49:20
thought it was my stereo which was turning itself on in the night but ive disconnected that aswell as the power sounder and the boot light. and still i keep getting a flat battery every few weeks. ive changed the battery for 3 different types. and all tested good each time, are there any other common drains on the omega it could b? :(
I had the same problem on my -96 omega 2.5v6, it turned out to be wrong in the electrical box to the sunroof. ;)
Title: Re: battery going flat
Post by: scottambrose on 27 October 2012, 08:28:58
as i work at a motor factors ive charged the battery to 100per cent and tested and its come up ok. so i put it on ansd tested again on our tester and the reading this morning is axactly the same within .1 of a volt to last night. so the drain must be intermittant, i also tested the drain with the multimeter in series, on two of our vans and that read the same as on my car at 25. think i will keep testing the battery every few days and see how much it drops
Title: Re: battery going flat
Post by: Andy H on 27 October 2012, 19:30:06
http://www.toolstation.com/images/library/stock/webbig/98689.jpg?rand=576444555

this is the multi meter and ive set it to the 200 on the right hand side next to the v
That looks like the 200 Volt AC range :-\. You need to be reading using one of the 'A' (Ampere) scales.

The trouble with using a hobby meter to measure current in a car is that when things are switched on the current can exceed 10 Amps but as things shut down the current should drop to a few milliamps. If you use the 10A range (using the 10A connection) you won't be able to read currents below about 10 milliamps (depending on how many digits on the display).

If you connect the leads to the 'normal' connections on the meter (ie not the 10A connection) as soon as the current exceeds about 250 milliamps the fuse blows inside the meter.

Small Print.......
Hobby multimeters will tend to show a reading if used to measure DC voltage while switched to the AC voltage range (but with a fudge factor of square root of 2 to give an approximate RMS voltage).

 
Title: Re: battery going flat
Post by: ffcgary1 on 27 October 2012, 19:57:27
Start with the simple stuff first, pull all the interior bulbs first and and include the boot / tailgate lamp as well, then see if the battery still goes flat, also you need to check the output from the alternator because if it is fubar then you will always have the problem
Does your car have a factory fitted alarm system? if so check the power sounder is ok as this is also a problem area and could be causing your system to drain currant.
Title: Re: battery going flat
Post by: scottambrose on 27 October 2012, 21:42:28
Power sounded disconnected and removed boot light removed and disconnexted al interior lights and will see if it dips down again