Hello,

 

I have a problem with Start Stop function that is not working since yesterday. Basically when I will stop ( for example at the junction )  on my cluster will appear a sign with A circled and crossed and engine stays on all the time.  

 

Any advice much appreciated before I will go to mechanic and spend god know how much. 

 

Bartek

Hi, just check you have accidentally switched it off.

Or, it might have to do with a low battery. My four-year-old battery needs the car to run for 10 or 15 minutes before the stop/start will start to work as expected.

Press the Car button on the infotainment a few times  - it will eventually say why stop/start isn't activating. Mine sometimes says "power consumption too high" which I presume to mean it's busy charging the battery/heating my backside/doing something electrical. It may also say that the engine needs to be on because of the aircon (to stop it misting up on damp days).

 

If you've only been doing short runs then the battery may also be low on charge as @freelunch says. I charge mine over the weekend every few weeks with a Ctek smart charger and that seems to avoid issues once the car is up to temperature (ie. water temp. gauge on 90 in my case).

Mine did that when the battery was low on charge, i.e. about to die.

Car/battery was about 3 yrs old at the time. 

Thoughts as above; I've a mate who ha to replace the battery in his Superb with stop/start at 3 years old.

If you have a decent charger and put the battery on charge for 48 hours continuous if possible. You will possibly find normal service is then resumed.

 

 

 

49 minutes ago, xman said:

If you have a decent charger and put the battery on charge for 48 hours continuous if possible. You will possibly find normal service is then resumed.

 

 

 

48 hours...blimey, is there not a possibility of overcharging it in that case?

(I have a CTEK MXS 5.0 but only have it connected until the lights tell me its charged...normally 4 or 5 hours.)

The start-stop system takes many parameters into account when deciding where to operate or not.

As discussed above, one of the main ones is the battery state of charge and the demand for electricity to run lights, wipers, seat/steering wheel heating, heater fans, etc.

Another big one is the aircon/heating and engine temperature.

 

If there is a big difference between the ambient temperature and the temperature asked for by the aircon/heat dials, the car will inhibit the start-stop if it needs the engine running to heat/cool the cabin.

I believe there is also an anti-fog censor which will keep the aircon running to provide dry air to the cabin to avoid a misted windscreen.

Any of these can temporarily prevent the start-stop operating, especially if the car is trying to satisfy combinations of these sorts of demands simultaneously.

 

I guess the message is - turn off all of these things and see if start-stop comes back before worrying about it.

I had the same issue due to a low battery charge. The Superb is not my daily drive car, so it sits idle, sometimes for weeks. I read about the Ctek chargers but then was told this is a better unit so I purchased this Victron IP65 12v/10 It is Bluetooth and the app has a nice interface, showing the stages of charge - Bulk, Absorption, Float and Storage. It also has a Regenerative function. It has a RRP here in Oz of $218.88 but I bought it on special here for $152.

5 hours ago, mandp said:

48 hours...blimey, is there not a possibility of overcharging it in that case?

(I have a CTEK MXS 5.0 but only have it connected until the lights tell me its charged...normally 4 or 5 hours.)

This is another reason I bought the Victron. It can be left on indefinitely as it will switch to Storage charge. See descriptions in the attached brochure.

Folder-A5-Blue-Smart-IP65-Charger-120V_EN_web.pdf

The Cteks can be left on charge and maintain the battery as necessary.

 

I remember when my dad used to bring his car battery in the house and connect it to a huge old battery charger when I was a kid (a few moons ago now). He'd top up the electrolyte and leave the covers off to vent. It hummed and fizzed a lot. Now we're all mollycoddled with new fangled self monitoring non-exploding technology   Don't get me started on making everything bluetooth enabled...

1 hour ago, unclerichy said:

Don't get me started on making everything bluetooth enabled...

Not a fan of BT?  I have other more sophisticated BT enabled chargers for my hobby of RC aircraft and find the information on Ah charged and history retention invaluable. Whilst I’d prefer WiFi, BT is a satisfactory alternative. 

BT is great but there's no need to put it in everything. Using an app to control my pressure washer? WTF! I'm talking to you Karcher 😅

18 hours ago, mandp said:

48 hours...blimey, is there not a possibility of overcharging it in that case?

(I have a CTEK MXS 5.0 but only have it connected until the lights tell me its charged...normally 4 or 5 hours.)

 

Smart chargers will tell you a battery is fully charged when the absorption phase charge current (with approx 14.5v applied) drops to around 10% of peak bulk/absorption current (i.e. down to approx 500mA in the case of a CTEK 5A charger), or the absorption phase times out (approx 8hrs in the case of the CTEK)

 

This of course is not true, at best the battery will be at 90% but could be considerably less if the battery is tired or got stubborn hard sulphation or the cells are unbalanced significantly. Most smart chargers then switch eventually to a maintenance or float mode where the charge voltage is lowered to around 13.6 volts. Initially charge current will drop to zero until the residual surface charge is dissipated, and then the current rises again to somewhere below the 10% level. The charger can be left on indefinitely in this state as the float voltage is well below the gassing voltage for a lead acid battery. Because of the chemistry and construction of lead acid, the battery will continue to charge, the charge current will continue to drop towards zero as the battery is fully charged. IME this topping off charge will take at least 2 days, considerably longer still with a tired battery to reach somewhere near full (provided the internals of the batterry aren't too far gone)

 

For information, the standby current taken by my Superb's electronics when its parked is approx 15mA average which means it will drain the battery by approx 0.3Ah per day. On top of this, batteries experience self discharge due to various reasons, age, temperature, internal condition etc. This internal discharge (and cell imbalance) is impossible to monitor externally and is likely the major reason the car's battery management gets out of whack with battery's true SOC and HOC.

 

So its always worth a good lengthy (min 2 days) charge before writing off a battery, but first check the charger supports the float/maintenance mode.

 

 

Edited 3 May, 20215 yr by xman

Thank you so much for that, `xman`.

Some of it I understood...most of it I did not.

So, can I ask...my car is less than 2 years old, has less than 6000miles on the clock, has never failed to start, the Stop - Start` has always worked as far as I know...I have the CTEK 5 charger...can I leave it charging for 2 days non stop, as you indicate above, without doing the battery any harm and hopefully some good?

Thank you.

1 hour ago, mandp said:

...I have the CTEK 5 charger...can I leave it charging for 2 days non stop, as you indicate above, without doing the battery any harm and hopefully some good?

 

Yes the CTEK 5 charger is safe to leave connected as it goes into float mode once the battery is "considered charged"

 

Ctek mxs 5.0 manual

 

 

 

Just make sure you connect your charger in the correct way to your car. Positive lead to the positive battery terminal, negative lead to the chassis tab on the engine bulkhead and NOT THE NEGATIVE BATTERY TERMINAL. This is so the battery mangement on the car can monitor the charge going into the battery.

Edited 4 May, 20215 yr by xman

Wow, what a lovely response to my question.

Thank you once again, `xman`.

I've got it now.

Best Regards

Mike.

On 04/05/2021 at 00:20, xman said:

 

Yes the CTEK 5 charger is safe to leave connected as it goes into float mode once the battery is "considered charged"

 

Ctek mxs 5.0 manual

 

 

 

Just make sure you connect your charger in the correct way to your car. Positive lead to the positive battery terminal, negative lead to the chassis tab on the engine bulkhead and NOT THE NEGATIVE BATTERY TERMINAL. This is so the battery mangement on the car can monitor the charge going into the battery.

Any chance of showing where exactly there's a good chassis earth point for this in the engine bay? I was looking for somewhere to clamp the neg to and didn't see an obvious good place

10 minutes ago, AlVal said:

Any chance of showing where exactly there's a good chassis earth point for this in the engine bay? I was looking for somewhere to clamp the neg to and didn't see an obvious good place

The chassis mount is here at the top of the picture.

I posted a similar pic elsewhere

 

 

 

How do people get on with undoing the nut on the negative point? I'm currently using clip-on leads instead as when I start to undo the nut the pressure of the terminals attached to the bolt means they push themselves up it and I'm worried that they'll push themselves all the way to the end and then fall off.

A bit late to the thread, but wondered if it was a DPF cycle clean, engine details weren't specific.