Low Battery Warnings Again

[ms10]

 

Last winter we were getting low battery warnings on our 1.4TSI Octavia estate despite it being only six months old. We got it checked out at the dealer's but they reckoned both the battery and alternator were fine. It's a stop-start car with a non-AGM battery.  We saw no warnings over the summer.  I should also say that even over long journeys the stop-start rarely, if ever, kicked in.

 

This winter it's the same story, but worse.  Over the course of 8 days I performed a full charge with a CTEK MSX 5.0, then drove a round trip of 120 miles, then on the eighth day got a low battery warning. 

 

I don't have day time lights enabled, but do have a dashcam connected via USB ( this is not powered during engine off). We're also low mileage (11000 miles in 18 months) with a fair number of short tips.

 

I have the car booked in again for end of December for reevaluation. If the dealer says the same as last time what options do I have? Should I insist on an AGM battery?  Would it make a difference?

 

It seems crazy that I'm having to charge an 18 month old car every two weeks. 

 

Edited 9 December, 2017 by ms10
Additional text

[SWBoy]

Vehicles with stop-start should always be fitted with either an AGM or EFB battery.

 

AGM & EFB Batteries Explained

 

My 2015 Octavia is still on the original battery, tends to be only driven once per week when the stop-start works as I would expect it to once we've driven more than 5 miles, and the battery has never needed to be charged.

[ms10]

The battery is a MOLL EFB 59Ah

[MoggyTech]

1 hour ago, ms10 said:

The battery is a MOLL EFB 59Ah

My car (1.4SE) uses MOLL EFB 69Ah so it looks like your battery is 10Ah short of standard.

[ms10]

 

16 minutes ago, MoggyTech said:

My car (1.4SE) uses MOLL EFB 69Ah so it looks like your battery is 10Ah short of standard.

Interesting, as mine is the SEL. So with the added satnav (and other features) in the SEL you would expect a higher battery demand than the SE

 

[MoggyTech]

47 minutes ago, ms10 said:

 

Interesting, as mine is the SEL. So with the added satnav (and other features) in the SEL you would expect a higher battery demand than the SE

 

Indeed, either your battery has been replaced at some point, or the factory fitted the wrong amp hour capacity.

[SWBoy]

1 hour ago, MoggyTech said:

My car (1.4SE) uses MOLL EFB 69Ah so it looks like your battery is 10Ah short of standard.

Maybe not, my car is a 2015 1.4TSI Elegance with Amundsen sat nav and was also fitted at the factory with a 59Ah (CCA 320A) battery - build code J0S on the vehicle data sticker.

 

When it does give up the ghost I intend to replace it with a larger 70Ah (CCA 760A) AGM battery (and recode the battery management appropriately).

[ms10]

53 minutes ago, SWBoy said:

Maybe not, my car is a 2015 1.4TSI Elegance with Amundsen sat nav and was also fitted at the factory with a 59Ah (CCA 320A) battery - build code J0S on the vehicle data sticker.

 

When it does give up the ghost I intend to replace it with a larger 70Ah (CCA 760A) AGM battery (and recode the battery management appropriately).

 

Hi. Can you tell me what you mean by "recode the battery management"?

 

I thought replacing one battery with another is a simple operation. 

[octavia5]

Ross-Tech explain it here, if a new battery is fitted but the can is not recoded the battery management systems will not function correctly

 

http://wiki.ross-tech.com/wiki/index.php/Battery_Replacement

Edited 9 December, 2017 by octavia5

[MoggyTech]

46 minutes ago, ms10 said:

 

Hi. Can you tell me what you mean by "recode the battery management"?

 

I thought replacing one battery with another is a simple operation. 

Not these days. Systems are so complex they even need to know and learn the new characteristics of a replacement battery. The SOC module decides when the alternator needs to kick in, and the alternator is controlled by a clutch (fuel saving).

The days of car DIY for most people have long gone.

[BigEjit]

@ms10 when you recharge the battery, do you included the battery minder on the negative post or just fit the charger to the battery post clamps? 

 

You might need a quiescent drain check to see how much electrical load is present when the car is locked and sleeping. This will tell if there’s something draining the battery charge when parked up overnight or longer.

 

Dashcams or any plug in gadget put more load on the battery unless they have an effective power management system or are disconnected when the car is parked up for a few days. They can add to battery lifetime wear or hold it below full charge long enough to cause damage. 

 

Otherwise the battery capacity could be down slightly due to a discharge event in the past partially damaging the battery internals. Batteries are also sensitive to being held in a discharged condition too long. Even new cars in the assembly plant and esp dealerships, can get flat batteries from misuse that need changing out. Moreso if the car was stored for a month or more somewhere. 

 

And another one, If you park up in a garage and never lock the car, it keeps it electrically active for longer putting more load on the battery, draining it a little further, needing a little more time to get fully charged next time out on a trip. 

 

There will be a date code on the battery top somewhere. This should pre date the production date of the car by no more than 5 weeks if it’s the original one fitted. After the build date, it’s a replacement.

 

2D bar code snowflakes on the top labels of the batteries are for scanning the battery to the car build spec to prevent mix ups on the assembly line.

Edited 9 December, 2017 by BigEjit

[ms10]

@BigEjit,  Thanks for your reply and advice.  Much appreciated

 

I'm charging the battery now and when doing so always connect the negative lead to the earth post of the car chassis, not the negative terminal of the battery (see photo). 

 

The photo attached shows the battery. I can't see anything date-specific.  The car was built to order in April 2016.

 

The DashCam is permanently connected to USB, not 12v, so shouldn't draw power when ignition is off.  But i've now disconnected it to see if my problems go away.  The car is locked when not in use.

[flybynite]

That looks like an 027 sized one. Easily upgraded to an 096 sized one. There is a bit of a write up for a golf MK7

 

However mine has an 096 sized 69Ah and it throws up warnings quite a bit too but nothing really wrong with the battery, I think it is just a bit over sensitive to be honest.

 

In fact infotainment is bleating that the 12v is almost flat just now. Haven't had my meters on it yet but it starts just fine. Although some things stop working. Bit of a cold snap always gets batteries, combined with less daylight, more lights and things like heated seats, heated screen, especially with a few short runs. These cars take a bit more power to run than a 70s Escort

 

Can't go much bigger than the one I have but will be having a look when the battery needs replacing. It did get the bigger 180A alternator though which is helpful.

[ms10]

@flybynite  It's an interesting point you make about over-sensitivity of the warnings.  Tbh, I've experienced no symptoms other the warnings.  Everything works fine and the car starts first time, every time.  We don't really use anything current heavy. We don't have heated seats, and rarely have to use rear screen heater.

 

I have a simple Ring voltmeter which connects into the cigarette lighter socket:

- When we get warnings it reads 11.4V

- Immediately after a short drive it reads 12.2V

- Three hours after a short drive it reads 11.8V

- I've just completed a charge with my CTEK and it now reads 12.0V

 

 

[BigEjit]

The Date code should be on the -ve terminal and be week and year numbers  in 4 digits.

 

I think the 2D code shows 20/03/16 so might have 16/12 on the -ve terminal. Therefore original battery for April build.  (Guessing mid April!)

 

Connections are ok.

 

So long as there are no abnormal power drains in the electrical system and the additional charge time is sufficient, the battery could just be on its way out. Cold weather highlights weakened batteries anyway. Batteries on an average vehicle usage pattern should be good for 10 years unless they have been mistreated in some way. The time period between factory assembly line and customer collection date is a high risk point for damaging batteries but impossible to check for instances where outside assistance was needed. Frequent short trips and long stand times also hurts battery longevity.

 

if you get a dealer to check it, by driving there you are adding charge to the battery which will hide it’s true condition. Will be best to have it checked after it’s stood for a few hours so it’s had time to stabilise (overnight would be best).  Also make sure it’s not been charged in the days ahead of the dealer visit otherwise it could show an artificially high output.

 

A hard reset has also been known to sort out Ecu glitches and misinformation (Disconnect and reconnect battery!!!)

[ms10]

@BigEjit The dealer told me they would perform a full charge, leave it overnight and evaluate it the next day.  Though, fat chance of taking it in with a low charge.  We're driving back to Sussex from Cheshire the day before....

 

Even if the battery is "healthy" I'm going to push as hard as i can for a replacement, preferably larger and/or AGM.  

[BigEjit]

2 minutes ago, ms10 said:

@flybynite  It's an interesting point you make about over-sensitivity of the warnings.  Tbh, I've experienced no symptoms other the warnings.  Everything works fine and the car starts first time, every time.  We don't really use anything current heavy. We don't have heated seats, and rarely have to use rear screen heater.

 

I have a simple Ring voltmeter which connects into the cigarette lighter socket:

- When we get warnings it reads 11.4V

- Immediately after a short drive it reads 12.2V

- Three hours after a short drive it reads 11.8V

- I've just completed a charge with my CTEK and it now reads 12.0V

 

 

Those figures seem a little low. Check the meter with the engine running. Should see 13.5 to 14v peak with the alternator engaged to verify the meter accuracy. Otherwise the battery is weaker than it should be. 

[ms10]

1 minute ago, BigEjit said:

Those figures seem a little low. Check the meter with the engine running. Should see 13.5 to 14v peak with the alternator engaged to verify the meter accuracy. Otherwise the battery is weaker than it should be. 

 

Yep.  Engaged, during driving I see 14.9V.  After an hour or two into a long drive the alternator will typically disengage to show 12.9V, which quickly degrades to 12.0V when off.

[BigEjit]

Down to the dealer then to see what they can find. They will only replace like for like as AGM cost more than EFB unless you dip your pocket.

[MoggyTech]

Those voltages indicate a battery that is about to fail. Optimal reading is 12.5 volts one hour after a full charge. Slight possibility something is drawing too much current when all modules have gone to sleep, but faulty battery is more likely.

[KevC_Derby]

A charging voltage of 14.9v is way too high! 13.8v is the standard output from an Alternator for a nominal 12v system (1.2v per cell for 12 cells).

[SWBoy]

11 minutes ago, KevC_Derby said:

A charging voltage of 14.9v is way too high! 13.8v is the standard output from an Alternator for a nominal 12v system (1.2v per cell for 12 cells).

The output voltage from an alternator is both charge and temperature dependent - at lower temperatures the voltage is higher - but having said that I agree that 14.9V is too high, the highest you should see is 14.5V and even then only with a well discharged battery at cold temperatures.

 

At 14.9V the battery will be gassing and drying out which will permanently damage it.

[KevC_Derby]

45 minutes ago, SWBoy said:

The output voltage from an alternator is both charge and temperature dependent - at lower temperatures the voltage is higher - but having said that I agree that 14.9V is too high, the highest you should see is 14.5V and even then only with a well discharged battery at cold temperatures.

 

At 14.9V the battery will be gassing and drying out which will permanently damage it.

Sorry, 14.2v for the Alternator Max for a 13.8v Battery.

[SWBoy]

1 hour ago, KevC_Derby said:

Sorry, 14.2v for the Alternator Max for a 13.8v Battery.

We'll have to agree to disagree on that one - my figures are based on when I was (a hands-on) Electronics Manager at a global automotive consultancy.

[KevC_Derby]

Similar experience, although mine off highway with less Power Management on my kind of products.