Hi Guys.

 

Last service I was told battery was worn out.Fair enough,car is nearly 6 years old.Checked voltage,alternator putting out 14.1 volts,but resting voltage goes from 12.4 straight away and drops to 11.7-11.8 volts  the next morning.Weird thing is car never gives a hint of struggling to start.I know I have to get a new battery soon but my question  is - will a run down battery cause any other problems. 2014 Octavia manual estate

On 26/08/2019 at 03:30, shempy said:

will a run down battery cause any other problems.

As well as starting issues you could also get problems with an electrically assisted PAS, random fault codes with pretty much any system, weak lights,...

 

With those voltages the battery is goosed for sure. Murphys law states the battery will fail at the most inconvenient time. You will also be running at full alternator load all the time = slightly reduced MPG.

 

I guess start stop will stop working

I had my battery replaced after several attempts, over 2 years, to make a warranty claim. I did not have any real problems over this period, apart from the STOP/START failing to operate and I got the occasional '12 Battery Low drive to...'

All the diagnostics had shown everything to be fine and dandy. A new battery was fitted in the last month of the  3 year warranty and so far all is well.

On 26/08/2019 at 03:30, shempy said:

will a run down battery cause any other problems

While it has enough juice to start the car it shouldn't be too bad. The real problems may come when car fails to start. May be a good idea to keep stop start deactivated, although it probably won't be active if battery is low.

 

1 hour ago, OldBoyScout said:

While it has enough juice to start the car it shouldn't be too bad. The real problems may come when car fails to start. May be a good idea to keep stop start deactivated, although it probably won't be active if battery is low.

 

Automatic engine stop-start is disabled if battery voltage falls too low, Eg. faulty battery. With error message in matrix display status "LOAD TOO HIGH".

On 26/08/2019 at 03:30, shempy said:

Hi Guys.

 

Last service I was told battery was worn out.Fair enough,car is nearly 6 years old.Checked voltage,alternator putting out 14.1 volts,but resting voltage goes from 12.4 straight away and drops to 11.7-11.8 volts  the next morning.Weird thing is car never gives a hint of struggling to start.I know I have to get a new battery soon but my question  is - will a run down battery cause any other problems. 2014 Octavia manual estate

 

Don't know what bit of Oz you are in but in the UK that battery probaly wouldn't see you though the next winter. They are not the best fitted as standard, mine didn't last 4 winters. Replacing the crappy Moll EFB battery with a good Varta 096 AGM was best move I have made in a while.

5 hours ago, flybynite said:

Don't know what bit of Oz you are in but in the UK that battery probaly wouldn't see you though the next winter.

I believe they have winter in Oz when we have summer here, so the OP will have gotten through most of the current winter and be getting into spring.

 

9 hours ago, Warrior193 said:

Automatic engine stop-start is disabled if battery voltage falls too low, Eg. faulty battery. With error message in matrix display status "LOAD TOO HIGH".

That is almost what I would expect, but if it has happened to the OP he hasn't mentioned it. I have found that when the voltage is a bit low, e.g. after starting off when the car has been parked up for a few days, or if the battery has not recovered from previous stops and starts, the system will keep the engine running when the car is stationary rather than stopping the engine as happens when the battery is well-charged. I have never seen the LOAD TOO HIGH error message, but I once got a message telling me to drive the car to charge the battery, which I think must be the message that Gregoir is referring to above. There is a thread on here where people have permanently disabled stop-start by changing the value of the relevant voltage in the car's settings, and I don't think they would be happy doing this if they were going to be seeing error messages.

 

Even with a good battery there will be times with stop-start when the voltage has taken a hit and the engine keeps running when the car is stationary. If the battery is not so good there will need to be more engine running while stationary to maintain the charge, so there will be an increase in fuel consumption. Although the engine will be running a bit more and stopping a bit less, it may not be enough for the driver to notice, as it could still be very similar to what happens normally. This could be what is happening with the OP's car, as the battery still has enough power to start the car in the morning, and he seems to have been alerted to the battery condition by the people who did the service rather than by anything he noticed himself.

 

Assuming the deterioration of the battery is at a relatively early stage and the stop-start is still stopping the engine from time to time, would it be better to switch off the stop-start or to leave it on? Switching it off might prolong the life of the battery a bit more, but the car will use more fuel if the engine is running.

 

There is a lot of clever tech in these modern cars to warn you if something isn't right, and I am thinking that while the car starts OK and drives OK with no error messages it is probably OK.

 

Thanks for all the feedback guys.Car is bog standard-no stop start,thank god.Have replaced battery with a Varta D15 all good now.

4 hours ago, OldBoyScout said:

I believe they have winter in Oz when we have summer here, so the OP will have gotten through most of the current winter and be getting into spring.

 

I know, I lived there for a while, it depends on where it is as to how much of a 'winter' it recieved. Which is why I asked....

 

4 hours ago, OldBoyScout said:

There is a lot of clever tech in these modern cars to warn you if something isn't right, and I am thinking that while the car starts OK and drives OK with no error messages it is probably OK.

 

The only thing that warned me of my battery being knackered was start stop not kicking in (but lots of other possible reasons for that) and Kessy stopping working (as the BCM shuts down the non essential systems due to voltage drop). If you dont have that fitted you would not know.

 

Next indication was it did not start one cold morning, proper flat. Happened quite a few times that winter. No warnings the night before.

 

With a recharge and recondition it did the summer and found its rightful place at the tip before the next winter.

 

3 hours ago, shempy said:

Thanks for all the feedback guys.Car is bog standard-no stop start,thank god.Have replaced battery with a Varta D15 all good now.

 

Good move, the 1.4 is not the hardest of engines to start and you may have gone through another year, but at that age it is due for a change at some point.

 

You shouldn't need it, but others might benefit from fitting the biggest battery that will fit (which is the 096 size). If you live somewhere where cars are harder to start maybe worth thinking about. Very comprehensive write up by a member on here @fabdavrav on the VW Golf forum

 

Either way you really should have the car coded to tell it there is a new battery. It stops charging at the lower capacity of a failing battery. It learns this and does not seem to unlearn until you change the battery serial number (as detailed HERE)

 

It is not going to blow up if you don't but it won't charge the new battery to its full capacity and could in theory shorten its life.