Hi all,

Just signed up after browsing. I saw a topic on charging batteries but I can't seem to find it now.

I have a 1 litre Fabia estate that I purchased 19 months ago. It is a 16 plate and currently has only 14550 on the clock.

With the pandemic, I only use it to go to work at the hospital which is only 2 1/2 miles away and have now started getting a warning that the battery is low and to start the engine.

Because of this. I have purchased a smart charger from Halford (noco genius5) and would appreciate some advice.

If charging with the battery still in the car, I believe, after reading the thread that I now can't find, that I should connect the red lead to the positive battery terminal and the black NOT to the negative but to the earth bolt that is linked to the negative terminal. Is this correct?

Also, it was mentioned that the battery will only charge up to around 75%. Is this also correct?

Would I be better off removing the battery, thus enabling the battery to be fully charged connecting the leads to both terminals?

It is an EFB battery and the smart charger manual says to charge this on normal 12V mode NOT the AGM mode. Do you think this is correct?

Forgot to say.

 

Thanks in advance of any help.

 

Dave

Not familiar with that charger, but sounds like you have things correct using terminal by the battery and not where lead on battery fits.

 

It is generally safe to leave battery in the car, however if it is not an automatic charger then need to avoid over-charging by removing after a set time but sounds like you have a smart charger which should shut itself down)

 

I suspect if you are just getting a warning (rather than being so flat starting is a problem) then hour or two should be sufficient to boost up the battery

 

Thanks SJ,

 

Yes only get the warning. It starts fine.

The smart charger I have does say it shuts down when fully charged so it shouldn't over charge the battery.

I am not going to charge it until next weekend now. Took the car on a 40 mile run today to see if that helps. That's the longest it's been for months!

 

Dave

As far as I have read, that charger that you bought from Halfords is a safe smart charger, battery maintenance unit, so it will charge the battery safely while it is connected to the car, and fully charge it and eventually just restart trickle charging when the battery voltage has dropped by a certain level.

 

So like my CTEK chargers, fit and forget if that car is in a garage with power.

 

The reference to the battery only being re-charged up to roughly 75% is how the car looks after its battery, ie attempting to never waste energy/fuel/emissions by keeping it fully charged up - but for my money, getting it fully charged up with a smart charger is a better way to look after these EFB batteries.

 

If the correct/smart VW Group battery post covers have been fitted to that car, the -VE post cover should try to get the message across that always connect to the local body earth post, this originally would mean while carrying out a jump start with another battery, but more recently it also covers any connecting from another power source to a car battery that has a bolted on battery management system dongle. Obviously the +VE post cover will not have any pictorial advice because connecting directly to that post is still the way to do things.

 

Edit:- from my experience of only 2 cars that have stop/start and EFB batteries, the car that has been used most regularly prior to movement restrictions, and never used for extremely short journeys, and is now 5.5 years old, has a battery in much more health than the car that is 1.75 years old and was left relatively used for the first 4 months of its life.  So despite what is claimed for EFB batteries, if the car is not used regularly then the battery will age quicker.  Also due to lack of use, as soon as I return either of our cars to the garage, they are re-connected to their CTEK smart charger-battery maintenance units - maybe overkill, but it seems to work for me. AGM batteries seem to live a lot longer, my own car is almost 10 years old, but low mileage and spends most of its life sleeping in the garage - and its original AGM battery is still okay but will get replaced this year to try to avoid letting me down when away from home.  The second car that has stop/start and an EFB battery is my daughter's and I think that she still connects it up to a CTEK charger/battery maintenance unit "now and again" while lockdown is in place, it will get used once or twice a week to go into work and maybe once a week when necessary, for food shopping - but she can not get that car into their garage so using a charger is only getting done as and when she feels it is necessary.

Edited 31 January, 20215 yr by rum4mo

I had a similar problem, so I have a smart charger too. I connect it directly to the battery terminals in situ and it works perfectly and safely. 

As for the VW 75% charge limit, I find it preposterous. (Why not fit a 25% smaller battery and save weight and energy?) Any energy saving will be minuscule and extending battery life unproven. All it causes is problems! So I disconnect the battery sensor that connects BCM (battery control module) from the negative battery terminal that has the added benefit of permanently disabling start/stop (another battery killer). Some things are over-engineered! 

^^^^ 

Because!

http://briskoda.net/forums/topic/465217-battery-type-problem

 

Thank you all for the replies and links. All very informative.

As I said, I took the car for a 40 mile run on Sunday. Got in this morning and no error message. So it must be down to lack of usage.

This has got me thinking though. Going on a 40 mile drive to keep the battery charged during the current lockdown, would this be classed as an essential journey if stopped by the police?

 

Thanks again

 

Dave

Going on a 40 mile drive solely to charge the battery is an ecological and financial disaster. WTF were VAG thinking when they designed a system that stops the battery from fully charging at the same time as introducing start/stop that puts massive additional demand on the battery. 

It is not an essential journey going driving to charge a cars battery.

Just keep using the charger to have the car with enough charge to be able to start when needed for essential journeys like getting shopping, medicines / doctor appointments, going to work or doing caring duties.

1 hour ago, TerFar said:

WTF were VAG thinking when they designed a system that stops the battery from fully charging at the same time as introducing start/stop that puts massive additional demand on the battery.

Mostly about CO2 figures, for regulatory and marketing reasons, I suspect.

Agree somewhat with you TerFar but in my case it is down to not driving as much due to the current restrictions. I now only use the car for work which is under 5 miles round trip where as before I was using it a lot more. That said, I didn't use the car excessively. Only for driving to golf and visiting family but I suppose that was enough for keeping the battery ticking over.

Don't assume that driving the car will charge the battery.

The alternator will only cut in if the voltage is at its low point or there is a high demand.

Smart charging is the way to go.

 

Thanks, AG Falco 

Thanks AG Falco. Will use the smart charger this weekend. Probably use it regularly at weekends after as well.

13 hours ago, AGFalco said:

Don't assume that driving the car will charge the battery.

The alternator will only cut in if the voltage is at its low point or there is a high demand.

Smart charging is the way to go.

 

Thanks, AG Falco 

That makes the whole system an even bigger ecological and financial disaster. A fast drive along an A road or motorway and your battery isn't recharged! It's bonkers.

The laws of physics haven't changed. Max recommended recharge rate for lead acid is 1/10th of the Ah rating - so a 70Ah battery should not receive more than 7A. Now - assuming the car can supply this consistently (mostly yes) - it would take ten hours of driving x 7A to get to a full battery. Much simplification here but you see how you need a perfect 10 hour drive to get back up to full charge. A fast drive along an A road won't do it. Or sitting on the drive idling.

The alternator does not produce a charge all the time by design.

The car tries to keep the battery charged from about 50% SOC to 80% SOC.

It wont want to charge the battery fully so that when you are braking the alternator will kick in and fast charge the battery at 15 volts.

This is using the kinetic energy of the vehicle which would be wasted by using the brakes more.

Micro hybrid charging system. Look here:- https://www.yuasa.co.uk/info/technical/micro-hybrid-hybrid-vehicles-explained/

''When the alternator is running it can typically consume up to 10% of the power produced by the engine.''

If the battery was already fully charged you would be over charging it.

The idea is that on a long journey the alternator only works when required.

This can help with both fuel economy and low brake wear.

 

My own car I have had from new in 2016 and is now above 50000 miles.

The brake pads and disks are all original and are only about 1/2 worn.

After swapping the car from a diesel I was hoping to hit 50 MPG in the summer with the petrol Fabia.

I am actually achieving more than 50 MPG during the winter and above 60 MPG during the other seasons.

This is worked out using actual miles travelled divided by the gallons filled to the brim every time I fill up.

My original Battery is showing no signs of low charge and the stop/start system still works fine.

I don't charge the battery with any external charger at all.

 

It works for me.

 

Thanks, AG Falco

On 02/02/2021 at 07:44, David62 said:

Thank you all for the replies and links. All very informative.

As I said, I took the car for a 40 mile run on Sunday. Got in this morning and no error message. So it must be down to lack of usage.

This has got me thinking though. Going on a 40 mile drive to keep the battery charged during the current lockdown, would this be classed as an essential journey if stopped by the police?

 

Thanks again

 

Dave

 

On 02/02/2021 at 08:01, TerFar said:

Going on a 40 mile drive solely to charge the battery is an ecological and financial disaster. WTF were VAG thinking when they designed a system that stops the battery from fully charging at the same time as introducing start/stop that puts massive additional demand on the battery. 

 

Considering how much (or rather, how little) the car's been driven over the past few months, a 2 mile journey isn't enough to fully recover the charge used to start the car and cold weather further limits things. I'm not surprised it's gotten to a point where it's warning of low battery.

 

With regular use and decent distances being driven, the system does not give fault. My car is 5 years old, yet gets driven daily on at very least a 10 mile each way commute, plus extras depending on how busy work is. Never missed a beat.

Had the same happening to my 2015 Estate (EFB battery) last year during cold weather and only 3-5 mile trips and doing a 10 mile trip made it happier. Eventually got in touch with my very knowledgable mobile mechanic in early summer. "Well it's probably nearing it's end, unless you turn off the stop/start, after 5 years it's been well used"

says he. On his advice got a new battery last autumn and surprise, surprise, no warnings since even in the last cold snap. I believe that VW recommend a new battery after 5 years too. I eventually found one for about £85 on ebay so don't get ripped off by Halfords or Quickfit who want about £130 I believe.

Yes, it seems like quite a "reasonable" proportion of people with EFB and using their cars for short journeys have ended up needing to replace their EFB, I think that with longer and frequent journeys even these EFBs along with Stop/Start can last  lot longer, I'm keeping an eye on the EFB in my wife's 2015 Polo and hopefully find the point when it needs changing before it lets us down.

 

There was also a quality/life issue with some brands over a manufacturing period, I seem to remember that that Polo has an Exide EFB.

Just to let you know, after 6 years with 59 Ah EFB Moll original battery died to the point of not even opening the car with the keys with outside temps of -13C. The low battery warning just showed up one week, and few months before only the start stop did not work.

 

So I bought a 60 Ah AGM battery of Varta for 90€ as EFB was around 30 to 40 euros more exp, replace it and coded as ''Fleece'' with the help of OBDeleven and so far everything fine :-).

 

Hope this helps if you don't find a cheap EFB replacement.

5 hours ago, NxRipper said:

Just to let you know, after 6 years with 59 Ah EFB Moll original battery died to the point of not even opening the car with the keys with outside temps of -13C. The low battery warning just showed up one week, and few months before only the start stop did not work.

 

So I bought a 60 Ah AGM battery of Varta for 90€ as EFB was around 30 to 40 euros more exp, replace it and coded as ''Fleece'' with the help of OBDeleven and so far everything fine :-).

 

Hope this helps if you don't find a cheap EFB replacement.

Yuasa is a good brand to go for, that's what i'll go for if mine eventually dies.

 

My Moll EFB battery seems in pretty good shape 5 and a half years in, halfords battery test comes back as being in perfect condition kicking out more than its rated CCA's. Start stop still works without issue. Obviously cant test capacity without an external tester that can fully cycle the battery. I might replace it come summer time anyway as that's generally when car batteries are cheapest, companies know car batteries most often die in winter and raise their prices accordingly, cheeky beggars lol

Just an update. Used my battery charger last week and haven't had a warning since so happy days. Hopefully lockdown might be eased a little soon and I will be able to use the car for longer journeys. I have now got another fault with the blower but will start a new thread for that. Thanks for all your help.

Dave.b