Battery warnings - normal?

[Web Ferret]

Just to add my experience to this.

 

After 50K miles and 2 years 11 months from new, my battery tested at 21% capacity today at a local Bosch service centre!

 

I am having it replaced under warranty but my daily round trip is 62 miles including 18 miles of motorway each way (everywhere from 70 to 0 crawl though).

 

No warnings though.  I asked them to check the battery as some starts were sluggish.

Edited 27 March, 2017 by Web Ferret

[Warrior193]

I rather suspect that this is going to become an issue with premature failure of the AGM batteries fitted (to the Octavias at least) with the battery never being fully charged unless you are descending a lot of mountains. Perhaps Skoda will have a rethink of the charging strategy (software update?) - or start supplying a smart-charger with every micro-hybrid sold. Perhaps this was the real reason that Skoda removed the battery SOC meter - so that owners could not see that the battery was never fully charged.

Has anyone with VCDS attempted to get into the battery charging system strategy? 

[bouff34]

But does anyone actually have an AGM battery...I have a MOLL EFB battery (in my 1.8TSi manual) as it appears others on here are stating? Those that are mentioning AGM have you actually physically checked what is under the bonnet. Not saying that you haven't but seems odd that similar cars are being fitted with different batteries?

[fabdavrav]

Right then this is an OLD topic on the MK7 Golf forum, & the same applies in this case, same engines, platform etc.

 

I have the 1.4TSI 140Ps & had the mid sized EFB in the tray from factory, & I found it getting low on 36mile trips.

 

The stop start kills them, plus full electric steering etc., etc,. Loads of people have this problems with these cars, plus VAG skimped on the size as considering the increased load compared to my old Fabia, the battery wasn't much bigger!

 

I swapped to a bigger AGM battery, also had to get a bigger insulation cover, all info on MK7 Golf forum in my how to guide:-

 

http://www.golfmk7.com/forums/showthread.php?t=7926

 

I also have e Ctek charger which does AGM & 12v supply so I can remove the battery & still keep the ECU's & BCM's all ok...

Edited 31 March, 2017 by fabdavrav

[Warrior193]

My My16 Octavia is definitely fitted with a AGM battery - in fact it is on its second battery due to the original being diagnosed as faulty within 6 months of delivery. The alternator was changed first, but that did not cure the problem with non-functioning automatic stop start. I have a feeling that the energy recovery strategy from regenerative braking (ie. not allowing the AGM battery ever to reach full charge) may possibly be part of the problem. 

I have seen comments from owners of Fabias saying that their battery is EFB, but I have also seen claims from Skoda that only AGMs will stand up to the rigors of auto stop start.   

[gregoir]

Just checked mine and it's an EFB type.

Maybe the AGM type were dropped last year? Google says the EFB type is designed for stop start duties.

[NikEd]

On 1/13/2017 at 19:29, ms10 said:

 

 

Our Octavia is 8 months old now, and to be honest we don't do huge mileage, maybe 4000 so far.  We do mostly short journeys (school runs, shops etc) and run a dashcam from the USB (so only draws current when ignition is on).

 

 

more than likely going to make an idiot of myself now but are you sure the USB only supplies power when the ignition is on? I know the cigarette lighter supplies power even without the key in the ignition (I use it to power a tyre inflator sometimes), and you can also turn the headunit on without the key so perhaps there is power to the USB also?

 

 

[ms10]

Hi NikEd

 

Yep, it's only the 12v plugs which remain powered when the car is locked. USB requires the ignition to be on to be powered. 

[ms10]

I recently purchased a Ring voltmeter, one which connects to the 12v socket in the dash, and it's been an illuminating experience (I wouldn't quite go so far to describe it as interesting).

 

The  ignition-off reading varies from 11.4v (warnings seen) to 12.4v (after long journey)  

 

When driving it will show 14.4v, which is the alternator engaged. 

 

During a recent 4 hour motorway journey it showed 14.4v for around 2 hours, before dropping to 12.4v, at which point I assumed the battery was fully charged and the alternator disengaged. 

 

The eco charging can be seen to kick in when coasting in gear, and when braking. The voltage jumps to 14.4v. 

 

Despite a full charge, the stop-start rarely kicks in. The car status saying that power consumption is high as the reason. 

[SuperbTWM]

7 minutes ago, ms10 said:

I recently purchased a Ring voltmeter, one which connects to the 12v socket in the dash, and it's been an illuminating experience (I wouldn't quite go so far to describe it as interesting).

 

The  ignition-off reading varies from 11.4v (warnings seen) to 12.4v (after long journey)  

 

When driving it will show 14.4v, which is the alternator engaged. 

 

During a recent 4 hour motorway journey it showed 14.4v for around 2 hours, before dropping to 12.4v, at which point I assumed the battery was fully charged and the alternator disengaged. 

 

The eco charging can be seen to kick in when coasting in gear, and when braking. The voltage jumps to 14.4v. 

 

Despite a full charge, the stop-start rarely kicks in. The car status saying that power consumption is high as the reason. 

 

Sounds like its more of a programming of the BMS issue rather than anything else

[ms10]

Do you not think it's normal?

[SuperbTWM]

1 hour ago, ms10 said:

Do you not think it's normal?

Well if your start stop still doesn't work after doing a good journey then there is something wrong.

 

Your ignition off reading is low though at 11.4, if it is like this regularly I can see why the car is inhibiting the start/stop until the battery has been charged.

[Warrior193]

Charging voltage should Depend on what battery type is fitted, charging voltage for an AGM battery should be higher than 14.4 (should actually be 14.7 volts) - which is why smart chargers have different settings. I note that some Octavia owners say that their car is fitted with EFB batteries (unlike my AGM) and I wonder if it's possible that Skoda/VAG have messed up somewhere in the various charging strategies. Any 12 volt battery regularly displaying levels as low as 11.4 VDC (assuming the measuring instrument is reasonably accurate) is virtually fully discharged - and will fail prematurely due to these regular low charge states.