Omega Owners Forum

Omega Help Area => Omega Electrical and Audio Help => Topic started by: tigers_gonads on 18 February 2018, 14:44:06

Title: weird charging problem
Post by: tigers_gonads on 18 February 2018, 14:44:06
A bit of a weird charging problem  :-\

I changed the regulator on the car maybe a couple of years ago.
On fitting the regulator, the most it would push out is about 13.5 volts which even though low I left it and decieded to look for the cause elsewhere when I had time.

Okay, finally remembered and had a bit of time on my hands since the middle of november (lost my piggin job  >:() I decieded to look into this last week.
First things first, with the battery holding a steady 12 volts over night I started it up (fired 1st time / no problems) and got the meter out.
I've got 12.7 at the battery. Also plugged the laptop in and that also gave a reading of 12.7 volts too.
Because the car hasn't had a run for a while, I took it upto York and back (about 100 miles with a few back roads thrown in) for a bit of a blast (heaters / radio / lights off.
Got home before lighting up time so popped the bonnet and checked the voltage across the battery to find at idle, its now pushing out a more healthy 13.8 volts  ???

First question is ............  Whats the hell is going on here ??
Second question is ............. With the normal running output of the alternator at around 14.0 volts, how is this varying voltage going to affect the various systems on the car ?
Reason is,  over the last year or so ive had a slow lambda sensor fault triggering a fault code when doing around 50mph / 5th gear with a very light pedel.
Also I have had problems with the vapouriser holding a steady pressure reading.

Is this volts drop possibly the cause of these little gremlins ?







Title: Re: weird charging problem
Post by: Bigron on 18 February 2018, 15:31:30
Why did you change the regulator two years ago; was the alternator not charging/low output? How sure are you of the condition of the battery - a dead cell, maybe?

Ron.
Title: Re: weird charging problem
Post by: cam.in.head on 18 February 2018, 16:09:09
sometimes an alternator wont give out the full charge voltage at idle. the revs will need to be increased to acheive this. then yes you would be looking more to 14.2v.and the regulator should maintain a voltage near to this with lights etc turned on.if the battery is in a good state of charge and in good condition then you should get a resting voltage of as near to 12.7 as possible with nothing turned on or idealy disconnected. when turning on ign you would expect a slight drop,then on starting car and idling it MAY go up but not necesarily to full charge voltage.it will also be a slightly lower voltage when measured at the battery rather than the alternator terminal itself but on the v6 at least its hard to get to it so a battery reading is good enough.
Title: Re: weird charging problem
Post by: tigers_gonads on 18 February 2018, 18:01:55
Why did you change the regulator two years ago; was the alternator not charging/low output? How sure are you of the condition of the battery - a dead cell, maybe?

Ron.

Charge light on nice and bright.
Regulator kicking out about 8 volts iirc Ron  :)

Definitely Foxtrot Oscar'd  ;D
Title: Re: weird charging problem
Post by: tigers_gonads on 18 February 2018, 18:11:56
sometimes an alternator wont give out the full charge voltage at idle. the revs will need to be increased to acheive this. then yes you would be looking more to 14.2v.and the regulator should maintain a voltage near to this with lights etc turned on.if the battery is in a good state of charge and in good condition then you should get a resting voltage of as near to 12.7 as possible with nothing turned on or idealy disconnected. when turning on ign you would expect a slight drop,then on starting car and idling it MAY go up but not necesarily to full charge voltage.it will also be a slightly lower voltage when measured at the battery rather than the alternator terminal itself but on the v6 at least its hard to get to it so a battery reading is good enough.


Understand what yeh saying bud  :)

Just to clarify ...............  Max volts were achieved from pretty much idle and constant upto 4 or 5000 revs with no tail off   :y

Tbh, i'm wondering if the rotor assembly is breaking down or clogged up with crap  :-\
The car is out in the damp 24 / 7.
Now wondering if a build up of crap is keeping the volts down when its not been run regularly  :-\

Or I may just be talking shite  ;D
Title: Re: weird charging problem
Post by: zirk on 18 February 2018, 18:43:10
If the cars not being used as a daily, I would pull the Battery out and slow charge it for 12 to 24 hrs then leave it unconnected somewhere cold for a few days to settle, measure again and anything from 12.6v upwards should prove to be a good battery.

If good, slap the Battery back in and redo your measurements again and in weeks time or so.  ;)
Title: Re: weird charging problem
Post by: tigers_gonads on 19 February 2018, 09:00:27
If the cars not being used as a daily, I would pull the Battery out and slow charge it for 12 to 24 hrs then leave it unconnected somewhere cold for a few days to settle, measure again and anything from 12.6v upwards should prove to be a good battery.

If good, slap the Battery back in and redo your measurements again and in weeks time or so.  ;)

I'll have a play this week when I find my battery saver and charge the thing  ::)

Must admit, I cant get my head around why it is kicking out a good 1 volt extra at all revs after a run  :-\
Also took the missus to work for 5 o'clock this morning.  A quick check of the battery before start up showed 12.2 volts with no frost.
Checked at fast idle and it showed a niceish 13.6  :-\

Also, has these fluctuating voltages been affecting the various niggley codes and readings ?
At the end of the day if the electronic bits an bobs on the car are calibrated to read accurately at 14 volts, it must be making a difference to them  :-\
Title: Re: weird charging problem
Post by: Kevin Wood on 19 February 2018, 11:00:00
Firstly, bear in mind that, if the alternator is being loaded heavily trying to replenish a partially discharged battery, its output may well drop a little until the battery is fully charged. This probably explains why it improved a little after a run.

I would still expect to see it the other side of 14V ideally, though.

First things to check are the crimps on the battery terminals, as these can work loose, and the ground straps from engine to chassis and up to the battery negative terminal.


Title: Re: weird charging problem
Post by: cam.in.head on 19 February 2018, 11:06:09
hi. The regulator sounds like its working or you would have an uncontrolled rise as you rev it up or a low voltage at idle. Most are supposed to try to maintain the output at around 14.2v .is there any way you can get to the wire at the alternator to measure it?  if voltage is good there it could indicate a bad joint somewhere.
Just one silly idea also !    Have you tried a different meter incase its the meter reading wrong and are you actually having any problems anyway or was it just because you measured the voltage ?
Title: Re: weird charging problem
Post by: cam.in.head on 19 February 2018, 11:08:16
Sorry there if my reply just said what kevin said!. I think we replied at the same time !
Title: Re: weird charging problem
Post by: Kevin Wood on 19 February 2018, 11:09:13
Yep, if you can measure between the alternator output terminal and the alternator chassis it will eliminate the wiring to the battery. :y

It would be a good idea to charge the battery fully on a mains charger first, though, so you know it's not going to be pulling a lot of current from the alternator.
Title: Re: weird charging problem
Post by: Kevin Wood on 19 February 2018, 11:10:52
In addition, if any of the connections (battery terminals, etc.) gets hot when running, this is a good indication that there's a poor connection there.
Title: Re: weird charging problem
Post by: Bigron on 19 February 2018, 11:31:34
Only slightly off topic, but if you are concerned about quiescent current drain from the battery, I w-s persuaded to buy one of these via a different thread on here:-
https://www.ebay.co.uk/itm/Heavy-Duty-Battery-Disconnect-Isolator-Cut-Off-Switch-12v-24v/172096775398?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2648

Aside from being a useful safety device on a 17 year old car, there is an additional bonus if you want to monitor current drain. Normally you would need to disconnect the battery - usually the negative terminal - and connect the current meter between the battery and the car wiring. With this device, with the switch closed, simply connect the current meter across the device.
The meter, on its Amps range, will maintain continuity for when you open the switch on the device and you can happily read any current drain.
This obviates the need to reset everything due to a disconnected battery.

Ron.
Title: Re: weird charging problem
Post by: tigers_gonads on 20 February 2018, 10:56:37
In addition, if any of the connections (battery terminals, etc.) gets hot when running, this is a good indication that there's a poor connection there.




Already checked the top crimp Kev and its nice and tight  :y
If its not too cold / wet, ill get the ramps out and check the main output from the alternator and crimp.
Also, iirc, there is a bonding strap from the block to the chassis which I know can fail if caught with a trolley jack if yanked out without lowering it  :-X :-[
That may loose me a volt or too  :-\


As always ..............  Thanks lads  :)
Title: Re: weird charging problem
Post by: Kevin Wood on 20 February 2018, 13:02:36
Yep, if you suspect the grounding strap is knackered, an easy test is to get it running with a few electrical loads on and then measure the voltage between the alternator's case and the battery negative terminal. If there's more than a few tenths of a volt, something's not right.