New Karoq battery issue

[mgm105]

Hi guys! I've just joined your forum.

To cut the long story I'm an electronics engineer (it's my profession for the last 46 years ☺️) and half a year ago I purchased Karoq. After three months  I found that the start-stop system doesn't work as it did before: sometimes - it worked, sometimes -not. After search in the internet I started to suspect that my battery supplies too low voltage. I measured it with my Fluke directly on the battery terminals immediately after I stopped the engine. It was 12.5V and during 20 seconds decreased to something about 12.1V. I started the engine again, asked my wife to keep the revolutions about 2000/min and the voltage increased to 14.1V. In my opinion the alternator worked as it should. Next morning before starting the engine I raised the bonnet and measured the battery voltage - it was 12.0V.

I connected to the cigarette lighter my mobile phone charger equipped with DC voltmeter. It showed 11.8V (I'm an old bore - I tested this toy in my laboratory  - in the range 10 - 20V the measurements accuracy was excellent!).

Also I found that the measurement difference between direct battery terminals test and the phone adapter is always the same ~200mV. I suppose the reason is the voltage drop on wires and fuses.

I think there are only two reasons for such battery voltage drop: or there is any device with significant current consumption when the ignition is OFF, or my battery is defective. So during afternoon break I raised the bonnet and measured the current in the wire connecting the "negative" terminal of the battery to the chassis with DC Clamp Meter while the ignition was OFF and the car was locked. The test lasted 3 minutes. In the beginning there was 6.5 Amps current but after ~35 seconds the clamp didn't see any current at all (@ the full scale 10 Amp)!!!  Now I was sure there is no load draining my battery at night!

I've came to the Skoda service with all the meters needed, explained the problem and required battery replacement. It was rather hard battle but I won and came home with a new battery. Their electrician made new battery adaptation routine also.

Do you think that the battery problems were behind?! NO!!! The next morning on the way to my job (about 25 miles on highway) I asked my engineer to monitor the voltage with the mentioned above phone adapter. He reported the voltage 14.2V. But after 10 miles he exclaimed "Wow! It's only 13.1V now!" The speed was ~70 m/h and the tachometer showed ~2000/min! I was so astonished that took my foot from the gas pedal. "Wow - he shouted again - the voltage jumped to 14.3V!" I made this trick five times with the same result: gas depressed - 13.1V, no gas - 14.2V! And all this bull**** happens at the same speed with no change of the engine revolutions! Fairy tale! I think the only change is the info the gas pedal sensor reports to the car computer...

Can anybody explain this? All ideas will be appreciated.

 

P.S.

I wanted to make sure the new battery is OK so I found and purchased electronic battery tester:

The test results: SOC (state of charge) - 80%, SOH (state of health) - 100%

 

Michael

 

 

 

 

[Karock]

A most interesting post.

 

You have probably read on here two significant problems that owners of the 1.5 TSI cars suffer from:

 

1. The so called "kangarooing" when setting off in first gear especially when the weather is cold

 

2. A sudden drop in power in second gear when entering a roundabout, that does not respond to more accelerator but just dies.

 

Not all cars suffer e.g. mine has never Kangarooed but has had the occasional 2nd gear power loss.

 

One owner reported that the problems seem to be worse when more electrical facilities were in use i.e. Electric windscreen, heater etc.

 

Perhaps these problems are in some way connected with a sporadic battery voltage?

 

 

 

[Kenny R]

The battery management system in stop/start car is very complex and the battery is never fully charged to allow for energy recovery from the alternator when braking or deceleration. 

Your worrying too much and your original battery was probably perfectly serviceable.

There are many conditions that prevent the stop/ start system operating apart from a duff battery. 

Conditions for the automatic engine shut down (stop phase)

› The gearshift lever is in Neutral.

› The clutch pedal is not depressed.

› The driver has fastened the seat belt.

› The driver's door is closed.

› The bonnet is closed.

› The vehicle is at a standstill.

› The engine is at operating temperature.

› The charge state of the vehicle battery is sufficient.

› The stationary vehicle is not on a steep slope or a steep downhill section.

› The engine speed is less than 1200 1/min.

› The temperature of the vehicle battery is not too low or too high.

› There is sufficient pressure in the braking system.

› The difference between the outdoor- and the set temperature in the interior is

not too great.

› The vehicle speed since the last time the engine was switched off was greater

than 3 km/h.

› The front wheels are not turned excessively (the steering angle is less than 3/4

of a steering wheel revolution).

 

Conditions for an automatic restart (start phase)

› The clutch is depressed.

› The max./min. temperature is set.

› The Defrost function for the windshield is switched on.

› A high blower stage has been selected.

› The START STOP button is pressed.

 

Conditions for an automatic restart without driver intervention

› The vehicle moves at a speed of more than 3 km/h.

› The difference between the outdoor- and the set temperature in the interior is

too great.

› The charge state of the vehicle battery is not sufficient.

› There is insufficient pressure in the braking system.

 

Edited 14 June, 2019 by Kenny R

[skoda1982]

My stop/start does the same can stop at on set of lights. 2 miles down the road traffic lights stop/start will not work. i think its just the way the system works

 

[silver1011]

What brand is the battery?

 

If it's a MOLL then chances are it is defective. Skoda have been replacing them under warranty across several of their models for almost a year now.

[agedbriar]

2 hours ago, Kenny R said:

The battery management system in stop/start car is very complex and the battery is never fully charged to allow for energy recovery from the alternator when braking or deceleration.

Many thanks for that revelation!

In fact, I was a bit worried too.

[StEdmund]

If I remember, I generally turn off the start/stop system in my Karoq - because it's a bloomin' nuisance - but are there potential benefits from it in other areas that I am not aware of i.e. in areas other than a very slight saving in fuel?

 

[mgm105]

2 hours ago, silver1011 said:

What brand is the battery?

Varta.

[silver1011]

The odds of it being a duff battery are significantly reduced then...

[mgm105]

Anyway after battery replacement the "drain issue" has gone, it was "replaced" with the new one.

BTW I tested the battery on my friend's Tiguan - 3 years old - SOC (state of charge) - 88%, SOH (state of health) - 47%, verdict: REPLACE

[AGFalco]

If you have an EFB or AGM battery you need to test it with a battery tester that is programmed to test this type of battery.

A normal battery tester will always show an EFB or AGM battery as needing charging.

Unless you have charged the battery off the car first.

 

Thanks AG Falco

[xman]

6 hours ago, mgm105 said:

 

Do you think that the battery problems were behind?! NO!!! The next morning on the way to my job (about 25 miles on highway) I asked my engineer to monitor the voltage with the mentioned above phone adapter. He reported the voltage 14.2V. But after 10 miles he exclaimed "Wow! It's only 13.1V now!" The speed was ~70 m/h and the tachometer showed ~2000/min! I was so astonished that took my foot from the gas pedal. "Wow - he shouted again - the voltage jumped to 14.3V!" I made this trick five times with the same result: gas depressed - 13.1V, no gas - 14.2V! And all this bull**** happens at the same speed with no change of the engine revolutions! Fairy tale! I think the only change is the info the gas pedal sensor reports to the car computer...

Can anybody explain this? All ideas will be appreciated.

 

 

All cars with Stop/start are what are classed as micro hybrid. They have battery management schemes that include energy management and recovery to reduce fuel consumption and emissions.

 

Simply put, when you accelerate, battery charging is switched off, when you coast/ decelerate, battery charging is turned on to recover energy using the alternator. Of course its a lot more complex than that as power consumers need to be managed and battery SOC needs to be monitored. Target SOC is around 80%, so that there is capacity to recover energy, but enough to restart the car, or keep consumers going when stopped. A current sensor on the battery negative terminal allows the car to manage the battery state, (coulomb counting).

 

Look up the term micro hybrid and get your 46 yr old car electronics knowledge up to date.

[mgm105]

Thanks to AGFalco and XMAN for  this interesting information.

Michael

[Kenny R]

Also I hope your not connecting that battery tester across the battery when it’s still connected to the car as the BMS is very susceptible to damage from voltage spikes, hence the warning to always connect the negative lead from any charger or jump lead to the dedicated terminal normally on the bulkhead, and not to connect to the battery negative terminal.

[mgm105]

4 minutes ago, Kenny R said:

Also I hope your not connecting that battery tester across the battery when it’s still connected to the car as the BMS is very susceptible to damage from voltage spikes, hence the warning to always connect the negative lead from any charger or jump lead to the dedicated terminal normally on the bulkhead, and not to connect to the battery negative terminal.

I really connected the Battery Tester across the battery terminals - referring the manual. Well, I'll try your way.

[Kenny R]

18 minutes ago, mgm105 said:

I really connected the Battery Tester across the battery terminals - referring the manual. Well, I'll try your way.

Yes the manual for the tester would say to connect to the battery terminals. What I was pointing out is that you may have caused damage if you connected to the battery terminals with them still connected to the car. 

If you insist on using that tester,( that has been pointed out as may not be the correct one for AGM or EFB type batteries), then disconnect the battery from the car before testing, removing the chance of you causing more damage.

Or just embrace the fact that modern technology works and just leave it to do its thing

Edited 15 June, 2019 by Kenny R

[mgm105]

5 minutes ago, Kenny R said:

Yes the manual for the tester would say to connect to the battery terminals. What I was pointing out is that you may have caused damage if you connected to the battery terminals with them still connected to the car. 

If you insist on using that tester,( that has been pointed out as may not be the correct one for AGM or EFB type batteries), then disconnect the battery from the car before testing, removing the chance of you causing more damage.

Or just embrace the fact that modern technology works and just leave it to do its thing

The Tester has two modes: for standalone battery and for connected to vehicle battery...

[Rayc6779]

I have one of those distribution sockets connected for my dash cam, satnav and phone charger.  It has a voltmeter display to show it is switched on.

I have notced the voltage is 13.3 when power is applied but jumps to around 14.5 when slowing under engine break.   This is how the regenerative breaking is working.  Low current charge when driving but greatly increased current when slowing.

My car is 1.6TDI SE manual

[33q]

My car battery was totally flat last Sunday. No dash lights at all. AA got it started

 

The dealer identified a battery fault and replaced it. The new battery is 70 amp/hr and whilst I’m not certain the battery appears to be larger than the old one. 

 

1.5 DSG......anyone know if my battery has been upgraded?

[agedbriar]

Mine came with a Varta EFB Technology of 59 Ah.

As I understand, on start/stop cars the battery should be either EFB (Enhanced Flooded Battery) or AGM.

[rayx]

All new VAG cars and not just them have the new "green" energy management system, which utilise brake energy recuperation ... This stay behind the flat batteries left at 12V and lower state ...

It is based on Start-Stop system, but it can not be switched off by the switch as Start-Stop. Pulling the connector from unit J367 out can do the trick for both systems

 

 

Energy management.pdf

[33q]

1 hour ago, agedbriar said:

Mine came with a Varta EFB Technology of 59 Ah.

As I understand, on start/stop cars the battery should be either EFB (Enhanced Flooded Battery) or AGM.

 

As I thought....the new battery is bigger...checked my friend's Ateca and that is 59 Ah too.

 

They have applied a TPI update too (Battery related) ...I asked what it was and 'they are not allowed to tell me!!!!!!!!!!!!!!'.....but they did give me a TPI number 2031034/11

 

Anyone know what this is ....or why etc?

[agedbriar]

If they increased the capacity on account of fitting a common flooded battery, that probably wasn't a good decision, as the old tech batteries don't like the 15V charging bursts. (Even 15.2 V in my case.)

 

Edited 15 July, 2019 by agedbriar

[DaveWK]

My 1.6 SE-L dsg  td Karoq was delivered in September 2018. A couple of months later the dash panel screen showed a warning, "Battery voltage low. Take a drive or Recharge". That only occurred the one time.

1st July, Manchester Airport car park after two weeks away - battery completely flat. In the event of such a calamity I had taken the precaution of bringing my battery booster which was secured in the boot.

Without battery power the doors and boot won't open. Called the RAC.

Whilst waiting (a long time 'cos he went to the wrong car park) I had a look at the manual, which for some pedantic reason I had downloaded to my phone.  Discovered that the manual key concealed in the fob can open the driver's door when the plastic cover over the secret keyhole is prised off. Great, I'm in the car but cannot open the bonnet 'cos the passenger door panel covers the release lever; and the other doors and boot are still locked!

The manual provides the answer to the locked boot. Drop the rear seats, crawl in to the boot space, unclip a plastic cover near the lock, insert a screwdriver or similar implement and turn. Decided to wait for the RAC.

RAC technician arrived and immediately leaned in and popped the bonnet release. "How you do that?" I ask. "Brute Force", he replies. Checks the battery and gives it 'Nil Points'. Connects a booster, not even a click. Adds another-nothing. Connects long leads from his van and adds them. Looks like a hedgehog of connectors. Revs the engine of the van - gets a click and nothing.

Agrees the battery is completely not very good. New RAC branded replacement fitted.  All is good.

I had left a Nextbase dashcam on 'shock' setting to record only if the car received a good smack whilst parked. Will not do that again but I think the car battery was faulty to start with.

To avoid the problem in future I'll connect the dashcam to the battery booster, not the 12v car socket.

No doubt the dashcam pulls a little current in standby but shouldn't be enough to flatten a good car battery in a couple of weeks.

 

 

 

 

 

 

 

 

 

[DieselDriverVRS]

I find all this very interesting and possible Skoda may have issues with their batteries?  I have an issue were my alarm will go off in the middle of the night.... another thread..... but when the dealer looked at it they couldn't see a reason (logged it went off, but no fault code)....very odd....  having the need to take to a different dealer (long story) they informed me it was likely a battery issue and I should take the car on a long drive..... I questioned that as I do about 100 miles a day - motorway/a roads so suggested that would not be the fix.....

 

Maybe with all this "clever" tech the batteries are just not upto the job?