Didn’t work for me. AA came out, jump started the car and then followed me to dealer 25 miles away to ensure I got there as the dealer had to test the battery after charging overnight before Skoda would authorise the new battery. Took nearly a week to do this and source a battery during which they lent me a car.

To check the battery state of charge, the voltage measurement must be performed with the battery as close to no-load as possible. That means waiting 10 minutes, giving time to various systems to go to sleep again, after unlocking and opening the door arose them.

Will have a look at that tomorrow.  

@DSLNot exactly SKODA coming out to you,

but the AA operative if you leave the battery flat if that is going to happen.

8 hours ago, DSL said:

After several hours on charge yesterday the battery should be fully charged but this morning it was only up to 12.5V and the green indicator still showing on the battery.  I won’t be out until middle of next week and will see then if SS is playing.  If it’s not I’ll see what I can do re getting it sorted after NY. That’s complicated by the fact that my closest Skoda dealer is over 100 miles away after the closure of the Inverness one.  There is still VW dealer, for now, will see if I get pointed that way.

I'm assuming you are charging it with the battery still in situ rather than out of the car. If in situ, then I believe that it won't go above 12.5V after charging because of the S/S system. It is so there is some 'space' for any regenerative charge to be stored, controlled by some electronic gizmo connected to the battery - and is why you shouldn't charge the battery using the terminals direct, bypassing this gizmo.

Re the battery indicator 'window' - on lead acids these are not particularly scientific, they tend to just be an indicator of the electrolyte level and are a green ball that floats on it (often shining a torch over the 'window' makes it more apparent that it is a green ball you are seeing). As the electrolyte level falls, the ball disappears down the float tube and gives the impression of a darkening the 'window'. If your window is green, then that is probably the green ball and if so means the electrolyte level is OK. 

Yes, charging in situ and using the “prong” instead of the -ve terminal.  I haven’t been out since charging her, will take her for a spin tomorrow and see if SS is working. 

47 minutes ago, VRT24 said:

I'm assuming you are charging it with the battery still in situ rather than out of the car. If in situ, then I believe that it won't go above 12.5V after charging because of the S/S system. It is so there is some 'space' for any regenerative charge to be stored, controlled by some electronic gizmo connected to the battery - and is why you shouldn't charge the battery using the terminals direct, bypassing this gizmo...

 

That doesn't sound probable to me. When the battery is being charged by an external charger, the car doesn't have control over the voltage being applied. So although the 'gizmo' can measure the amount of charge being added, it isn't able to control it in the same way that it could if the alternator was supplying the charge (by varying the voltage setpoint of the alt).

I believe further charging by the external charger will improve the state of charge of this battery.

I have a voltmeter constantly connected and my findings are that the battery will recharge to full state of charge (12.7 - 12.8 V at rest, depending on temperature) if the journey involves enough downhill driving and decelerations. As long as recharging can be done without extra fuel consumption, there is no reason for the system algorithm to hold it back.

 

But yes, when charging needs to be done while the engine is consuming fuel, it will stop before reaching full SOC in order to keep the extra fuel consumption as low as practical.

 

Edited 20 December, 20205 yr by agedbriar

The fact that the algorithm won't fully recharge the battery if it has to be done at expense of fuel (it can afford that strategy since the EFB batteries installed in S/S cars can start the engine from a lower state of charge than the regular ones), poses a bigger problem in periods of reduced driving,  as a battery left to rest not fully charged at the outset, will sooner drop below 12.4 V and begin sulfating.

 

I've mailed a question to Varta, asking if EFB batteries are equally susceptible to sulfation as the regular LA, but haven't received their reply yet.

 

Edited 20 December, 20205 yr by agedbriar

Post #7 perhaps explains the 'gizmo' better -

https://www.briskoda.net/forums/topic/465186-battery-charging/

Interesting read, esp re disconnecting the SS sensor.  Not quite brave enough to try that yet but is this the cable that would need disconnected?  Don’t suppose just switching it off religiously achieves the same?

 

 I am looking at a trip next summer to NE Finland, CV permitting, that will involve some reasonably remote roads (from experience few other cars and no mobile signal, unusual in Finland) so having a battery I know is as full as possible would be a weight off my mind.

3 hours ago, DSL said:

Interesting read, esp re disconnecting the SS sensor.  Not quite brave enough to try that yet but is this the cable that would need disconnected?  Don’t suppose just switching it off religiously achieves the same?

I agree - I'd be reluctant to try disconnecting the SS sensor. Haven't given our under bonnet area anything more than a cursory glance since we took delivery, so haven't investigated the battery negative terminal set-up fully. But it would look as though the bit you have marked would be it - I think all it does is decide if charge being generated needs to go into the battery or not, so logically it would be the final 'switch' in the circuit going back to the negative terminal.

As to switching SS off religiously, I would think that would only stop the engine shutting down (when SS conditions would support) but the sensor would still be active in determining whether or not to charge the battery - and presumably it would still be seeking to only allow a charge to c.12.5V level. I'd leave SS on and see what happens. If the battery is on the way out, then I'd think the SS system would rarely kick in as it would be trying to keep the battery charged up, and if it does start operating then that would indicate things are relatively OK. I can't give examples from our car as its petrol and as yours is diesel then the SS set up parameters probably are not identical - for example the SS on ours will start working after just a few minutes / half a mile distance and that may not be how things should happen on the diesel.

14 hours ago, Wino said:

 

That doesn't sound probable to me. When the battery is being charged by an external charger, the car doesn't have control over the voltage being applied.

The car does have control - provided the charger is not connected directly to the negative terminal. As it says in the manual, you should connect the negative lead to the point behind the battery which should therefore mean the circuit passes through the 'gizmo'/SS sensor/call it what you will, and that will then enable it to control the level of charge it lets the battery reach before disconnecting the charging circuit. If you connect the charger directly to positive and negative battery terminals, then the state of charge is only controlled by the charger.

No mate, the gizmo just senses the current going in/out of the battery and - when engine is running - can instruct the alternator to modify its output voltage accordingly. The gizmo can't stop current from an external charger going in. It's not a switch.

Fair dos - but why then can't a charger be connected directly to both the battery terminals? The dealer was the one who told me about the negative connection to the negative block behind the battery as I was asking whether I could put my charger fly leads onto the terminal clamp bolts (the same as I have on another car)  without causing any probs.

So that the car can keep track of how much charge has gone in since it was last 'in charge of charging', I believe.

On 19/12/2020 at 19:17, agedbriar said:

To check the battery state of charge, the voltage measurement must be performed with the battery as close to no-load as possible. That means waiting 10 minutes, giving time to various systems to go to sleep again, after unlocking and opening the door arose them.

Did this first thing after leaving it for a decent charge yesterday, thanks fo the tip.  I’m beginning to sound a bit obsessive re getting as much juice in the battery but, cf my cars of the past, this is a bit of a learning curve and nothing better to do.  I’ve had a good read around the subject, and re disconnecting the J367 battery monitoring system and it varies from “no problems, I’ve run like that for umpteen tens of thousands of miles” to “it’s there for a purpose and removing it will invite the 4 horsemen of the apocalypse and plagues on us all at once” , hence I’m leaving it alone.  Well for now. 

 

Immediately after unlocking the car the DMM read 12.45v across the terminals.  Left it 20 minutes and then remeasured and it was up to 12.84v.  Will see what the SS does today but thinking it’s just coz it’s cold and the battery was a bit low from lack of use.  Paranoia mode = OFF!  

3 hours ago, DSL said:

 I’m beginning to sound a bit obsessive re getting as much juice in the battery...

 

For me, it's not only that EFB batteries cost twice as much as the regular ones and that installing another one calls for the input of the new battery data by the dealership, but it's also about taking proper care of my gear.

 

Edited 21 December, 20205 yr by agedbriar

I’ve seen posts where peeps have just bunged a new battery in and not reset anything, with no ill effects.  It does become a bit of a PITA of a new battery requires a trip to a dealer or indi to reset the system.  Batteries don’t look too expensive, ~£70 - £90, but the price goes up dramatically if you have to go in to a dealer for them to work their magic.

37 minutes ago, DSL said:

Batteries don’t look too expensive, ~£70 - £90 ...

 

EFB technology? Because that's what they should be in a S/S car (or the even more expensive AGM).

 

In fact, there are two S/S cars characteristics that shorten the life of common LA batteries. One is the numerous engine starts from only partly charged battery, the other the relatively high voltage quick charging (at up to 15 V), designed to best exploit the opportunities of charging for free.

 

Edited 21 December, 20205 yr by agedbriar

It was just a cursory look, was looking for 5TA915105B spec.  Will have a more thorough look later.