Omega Owners Forum
Omega Help Area => Omega Electrical and Audio Help => Topic started by: Lesopc on 20 July 2010, 12:10:54
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On Sunday night at half past midnight i drove my miggy 4 miles home from the bus garage where i work. During the journey eveything went normally (the only light on the dash was the engine management amber light due to a failed cam sensor) and i parked the car with the radio/cd player off,a/c off and lights off. When i went back to the car at 8.30am on Monday, EVERYTHING was dead. The battery was bought brand new in Nov 09 and is a high output diesel one (my miggy is a 2.0 petrol straight 4 manual). I have had a battery replaced under it's guarantee but just wondered if there might be another underlying cause. Any help might be useful.
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Have you measured for current drain ?
1st place to start
:y
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Have you measured for current drain ?
1st place to start
:y
Never checked that Dave, Do i just need an Ampmeter??? If all systems are off how can there be a current drain??
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I once had exactly the same thing...................I inadvently had pressed the fob button for the boot after locking the car and the boot light had drained the battery by Monday morning! :'( :'(
Is your boot open? :-/
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I once had exactly the same thing...................I inadvently had pressed the fob button for the boot after locking the car and the boot light had drained the battery by Monday morning! :'( :'(
Is your boot open? :-/
No the boot was shut and as i say, all systems were off.
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Have you measured for current drain ?
1st place to start
:y
Never checked that Dave, Do i just need an Ampmeter??? If all systems are off how can there be a current drain??
Checking for current drain will determine if somethng that should be switched off is still actually partially switched on and draining the battery - if unable to perform this yourself, have a word with your local autoelectrician - without knowing for certain that you have battery drain, and you didn`t simply leave a light on, you do not have a point to start diagnosing from.
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I am experiencing same problem I have put up post looking for new alternator. How do you test current drain and rectify it :-/
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First things first. Disconnect battery, Recharge OFF the vehicle for 24 hours. Leave to stand for 1 hour. Then, and only then, take voltage readings every couple of hours for the next 24 hours-ish
If the voltage maintains steady over this time.. the battery is probably good, if the voltage drops the battery is fubar and most likely the problem.
Once you have a battery that is known to hold its charge properly, place on the vehicle, ensure everything you think is off actually is, make sure all doors/boot closed. Take voltage readings for a further 24 hours.
If the voltage drops then something is "live" .. time to start systematically pulling fuses to find out what .. :(
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To test for curent drain, rather than Entwood's voltage drop, you need your multi-meter & leads set to read current. There's normally a 20 amp none fused connection and a 2 amp fused connection. Your battery lead needs disconnecting and the multi-meter connected in line with the battery lead.
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To test for curent drain, rather than Entwood's voltage drop, you need your multi-meter & leads set to read current. There's normally a 20 amp none fused connection and a 2 amp fused connection. Your battery lead needs disconnecting and the multi-meter connected in line with the battery lead.
Yep. Make sure you don't switch on anything that will draw serious current or it will blow the fuse in your multimeter and may destroy it.
Also, wait 15 minutes with the doors closed to ensure the accessory timer has expired.
Kevin
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Is this not the start of the Powersounder problem... like I had .... fixed the battery prob by removing the powersounder.... first sign of Powersound battery leak is
flattening the main battery... well it was for me..
doogie
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i would say no to powersounder as mine and ops car are both basic beasts which do not have alarms or powersounder, but i stand to be corrected ::)
i thought my alternator was struggling because i have just put an elite interior in i have know disconnected my seats to see if that changes anything failing that i could remove boot bulb as some have commented that it can stay on if not catched properly :-?
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Is this not the start of the Powersounder problem... like I had .... fixed the battery prob by removing the powersounder.... first sign of Powersound battery leak is
flattening the main battery... well it was for me..
doogie
Powersounder has been disconnected since before i became owner. Just had fobs fixed and was thinking of re-connecting it though.
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i would say no to powersounder as mine and ops car are both basic beasts which do not have alarms or powersounder, but i stand to be corrected ::)
i thought my alternator was struggling because i have just put an elite interior in i have know disconnected my seats to see if that changes anything failing that i could remove boot bulb as some have commented that it can stay on if not catched properly :-?
No as boot bulb is also out everytime.
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
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well i cant help you mate my clocks have died and stereo have not got a clue gone have to take it to garage soon!!!
tried and failed sorry. :'(
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
:o
I would never disconnect a battery with the engine running. This could land you in an awful lot more bother.
Kevin
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sometimes one cell does leak into another so one day it could be fine, the next its not ... free check at an auto centre.. kwikfit etc.
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
:o
I would never disconnect a battery with the engine running. This could land you in an awful lot more bother.
Kevin
Been doing this for years Kevin, whats the problem?
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
:o
I would never disconnect a battery with the engine running. This could land you in an awful lot more bother.
Kevin
Been doing this for years Kevin, whats the problem?
More recent electrickery doesn't like it. My Dad did similar recently with his Mk III Granada. As he pulled what was a fuse from a fuse/relay box, the engine died. But in doing so, it also seems to have fried something to do with the ABS ECU because he now has a permanantly lit ABS light on the dash. :(
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
:o
I would never disconnect a battery with the engine running. This could land you in an awful lot more bother.
Kevin
Been doing this for years Kevin, whats the problem?
Just my views .. nowt else ..
The battery acts as a "smoothing circuit" and "shock absorber" to the alternator. If the alternator is running and you disconnect the battery, then there is nothing in the circuit to "absorb" or "smooth" voltage spikes.
The voltage regulator will react to try and control voltages, but it is always reactive, so is a fraction behind what is actualy happening.
Thus it is possible for fairly large transitional voltages to occur. Many of the circuits in ECU's are very voltage sensitive, being solid state devices, such voltage spikes can damage them readily.
Older cars, like what I started on ( morris minor sidevalve, through to ford crossflows and upwards),, had very few electric circuits, no solid state devices and often a dynamo with a carbon pile voltage regulator !! They didn't care about transient voltage spike at all.
The same can't be said for todays "sophisticated" electronics.. which are IMHO .. far too fragile at times .. given the environment in which they operate.
I would, also, never disconnect a battery with the alternator running.
:)
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Do as mentioned above for Battery condition and drain, also worth checking your alternator output voltage, when running should be arround 13.5 to 14.2, if its less than this then pull the Neg off the battery while running and measure alternator volts again. As where having hot weather now, check that the fans dont kick in and mess up the readings.
Chris.
:o
I would never disconnect a battery with the engine running. This could land you in an awful lot more bother.
Kevin
Been doing this for years Kevin, whats the problem?
Just my views .. nowt else ..
The battery acts as a "smoothing circuit" and "shock absorber" to the alternator. If the alternator is running and you disconnect the battery, then there is nothing in the circuit to "absorb" or "smooth" voltage spikes.
The voltage regulator will react to try and control voltages, but it is always reactive, so is a fraction behind what is actualy happening.
Thus it is possible for fairly large transitional voltages to occur. Many of the circuits in ECU's are very voltage sensitive, being solid state devices, such voltage spikes can damage them readily.
Older cars, like what I started on ( morris minor sidevalve, through to ford crossflows and upwards),, had very few electric circuits, no solid state devices and often a dynamo with a carbon pile voltage regulator !! They didn't care about transient voltage spike at all.
The same can't be said for todays "sophisticated" electronics.. which are IMHO .. far too fragile at times .. given the environment in which they operate.
I would, also, never disconnect a battery with the alternator running.
:)
Yep, nail on the head, basically. An alternator's output is regulated by altering the current in the field winding which alters the magnetic field strength in the alternator and thus the current induced in the stator windings which provide the output.
There will be a residual field with no field current which means under low load conditions the alternator output voltage is uncontrolled. In addition, a change to the field current doesn't result in an immediate change in output voltage (the field winding is inductive, so it is not possible to change the current instantaneously anyway). The magnetic field takes time to decay (actually the same mechanism by which the winding is inductive) and while it does so, the alternator is delivering more current than the electrical system is demanding, so the voltage rises.
If there is a sudden reduction in load from the alternator (e.g. cooling fan stopping) this means the voltage will spike to a high level for a few milliseconds before, hopefully, stabilising again. The voltage regulator in the alternator might even become unstable and oscillate between very high and low output voltages,
Normally the battery will damp down this tendency by absorbing the extra current and preventing a dangerous rise in voltage but without it present any devices being powered by the alternator will instead absorb the spike. This includes engine, ABS, Autobox, Air bag ecu, any In car entertainment equipment, etc.
This equipment is protected, so it may not fail the first time you do this, but each time a spike hits their electronics the protection components are stressed and may fail so the risk is there, and it can be avoided by testing the battery and alternator condition with a multimeter while they are both still connected to the vehicle.
Kevin
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wow...i feel dumb know :-?
but happy your here if i ever need it 8-)
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wow...i feel dumb know :-?
....
We can sit ..... . numb together ..... in a corner! :-[ :-[ :-[ ;)
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Well. Im not going to to argue with you about the battery being a smoothing component, yes it has a resistive load and acts like a form of a capacitor against the alternator controlled voltage regulator, hence a voltage regulator of a alternator only works effectively whilst some form of current is being drawn from it, but whilst the engine is running then some form of current is being drawn, which should limit the alternators voltage output ratting. Guessing were are not going to agree on that one.
Maybe an idea, if you slightly disagree is to inform the AA and RAC on this one, as this is one of the checks they do to apprehend wether the alternator is doing its job as roadside testing for the alternator.
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Maybe an idea, if you slightly disagree is to inform the AA and RAC on this one, as this is one of the checks they do to apprehend wether the alternator is doing its job as roadside testing for the alternator.
Doesn't surprise me in the least but they aren't exactly the model of automotive diagnostic excellence. I'd rather get a multimeter out. The fact a car runs on the alternator alone only proves the alternator can power a fuel pump, a set of injectors and an ignition coil. These will work over a wide voltage range anyway. Measuring the output voltage under various conditions gives you a complete picture.
kevin
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Doesn't surprise me in the least but they aren't exactly the model of automotive diagnostic excellence. I'd rather get a multimeter out. The fact a car runs on the alternator alone only proves the alternator can power a fuel pump, a set of injectors and an ignition coil. These will work over a wide voltage range anyway. Measuring the output voltage under various conditions gives you a complete picture.
kevin
Ahh, dont be that hard on them Kevin, they do carry cable ties and insulating tape on board these days you know.