Would it be possible to configure the BMS to target a higher State of Charge for the battery using HEX-V2 and VCDS? e.g. target 90% SOC instead of 80%

 

Related to below topics regarding frequent low state of charge and fast degrading batteries on a 2018 Octavia 

Battery issues

Charging diagnostics

 

Thank you!

AFAIK there are no coding or adaptation settings in the BMS for the SOC target and hence have to assume that it's hard coded.

Well we have @ords whose car is still on it's original battery after 10 years, so any "issues" will be down to abuse of the battery.  My own AGM 096 original battery was over 7 years old when I changed it prematurely as I didn't want to be stranded anywhere.

 

If you want to hack the battery, my only suggestion is to code the Ah rating higher.  Why?  Because we had someone whose battery got coded as 7Ah not 70Ah and it refused to charge, as it was measuring "full" once programmed to 70Ah it charged, so by extension, you may have to increase the Ah rating above target to make it charge above 80% SOC.

 

I DO NOT RECOMMEND THAT YOU DO THIS AT ALL.

Please note - I am not a mechanic or expert in anything.

 

Did you try try, if possible and allowed, disconnecting the start/stop connector the battery negative post and seeing how things go with the battery driving with that disconnected.

 

Or have you checked to see if your battery is fully charging or has a bad cell or other fault so shows as fully charged but is not - or does not hold charge with use, might need another new battery if the current one got badly injured.  Modern "smart" battery chargers and maintainers are not very smart and easily fooled by batteries and humans.

 

Have bought a VCDS or asking before you do?

 

Edited 21 February, 20233 yr by nta16
ETA: Please note - I am not a mechanic or expert in anything.

My understanding is that the % limit on alternator charging is to allow capacity for regenerative charging - under those conditions, there could be a possibility of overcharging the battery. 

Please note - I am not a mechanic or expert in anything.

 

If it's possible and allowed for a 2018 car, and in Nirrain's country, to disconnect the start/stop system then I've seen at least one poster put they've used their car for three years with the start/stop negative post connector disconnected.

 

Someone like varooom would have to do all the tests with readout figures or graphs but I fully 100% (if not more) charged the AGM battery before fitting it my wife's 2015 Fabia Mk3, from the previous EFB, and I left the start/stop negative post connector disconnected for a while before I could get someone to 'code' the battery in.

 

Like varoom I changed the battery prematurely to avoid the slightest hassle as my wife uses the car on lots of very, very short journeys and is not as thrifty with the electric as I and she'd not tolerate any car problems having already experience two or three lifetimes of them.

 

Nirrain's got an EFB battery that keeps losing charge so could perhaps risk a journey or two with the start/stop negative post connector disconnected especially if he can monitor the situation with some sort of VCDS or the likes - not that I'm suggest any plug-in should be left in too much.

 

Thanks for all the input!

  

15 hours ago, varooom said:

Well we have @ords whose car is still on it's original battery after 10 years, so any "issues" will be down to abuse of the battery.  My own AGM 096 original battery was over 7 years old when I changed it prematurely as I didn't want to be stranded anywhere.

 

If you want to hack the battery, my only suggestion is to code the Ah rating higher.  Why?  Because we had someone whose battery got coded as 7Ah not 70Ah and it refused to charge, as it was measuring "full" once programmed to 70Ah it charged, so by extension, you may have to increase the Ah rating above target to make it charge above 80% SOC.

 

I DO NOT RECOMMEND THAT YOU DO THIS AT ALL.

 

My "less smart" 2013 Citigo had it original battery last for 9 years with more or less the same usage as the 2018 Octavia with infrequent use, except the citigo was used more for the very short trips. That is why I suspect the newer car being too smart for its own (or at least its battery) good.

 

It was the authorized Skoda mechanic that programmed the new battery when the first battery died after 3 years on the Octavia so I am inclined to believe it was done correctly, though your comment regarding missing the 0 in 70 does raise some suspicion

 

14 hours ago, nta16 said:

Please note - I am not a mechanic or expert in anything.

 

Did you try try, if possible and allowed, disconnecting the start/stop connector the battery negative post and seeing how things go with the battery driving with that disconnected.

 

Or have you checked to see if your battery is fully charging or has a bad cell or other fault so shows as fully charged but is not - or does not hold charge with use, might need another new battery if the current one got badly injured.  Modern "smart" battery chargers and maintainers are not very smart and easily fooled by batteries and humans.

 

Have bought a VCDS or asking before you do?

 

 

I have considered it, but from the very thorough analysis done by @RicardoM in Charging diagnostics my understanding is that the start-stop connector should not affect anything else and to me it seems that the car simply does not charge the battery sufficiently for good health but the start-stop system works as it should as long as the battery is fully charged (when done manually with a corded charger)

 

I have not bought VCDS yet but trying to gauge if this issue would be another argument for getting one - I would also like to change the high beam assist to work at a lower speed but find it hard to pay the price just for that convenience

 

13 hours ago, Warrior193 said:

My understanding is that the % limit on alternator charging is to allow capacity for regenerative charging - under those conditions, there could be a possibility of overcharging the battery. 

 

That is a very good point, but as I understand the 2018 Octavia does not have regenerative charging and even if the target was 90% shouldn't the BMS still protect the battery from overcharging?

3 hours ago, Nirrain said:

My "less smart" 2013 Citigo had it original battery last for 9 years with more or less the same usage as the 2018 Octavia with infrequent use, except the citigo was used more for the very short trips. That is why I suspect the newer car being too smart for its own (or at least its battery) good.

 

It was the authorized Skoda mechanic that programmed the new battery when the first battery died after 3 years on the Octavia so I am inclined to believe it was done correctly, though your comment regarding missing the 0 in 70 does raise some suspicion

That could be down to two different cars, so load on each battery is much different (heated seats/front and rear screens vs just rear) battery Ah, battery tech (Wet/EFB/AGM) and finally luck of the draw, where you got a duff battery fitted.

 

You might want to read this thread in full, to see how a car reacts to a 7Ah vs 70Ah rating being input, makes for a nice read.

 

As for VCDS, if you are planning to keep the car for any length of time, or a going to keep with the VAG stable, then it's a wise investment.  It's about 2-3 visits to the dealer/garage to pay for itself, a no-brainer in my book.  If not keep an eye out on here for 2nd hand VCDS sales (don't trust online auctions, they will mostly be fake)

Please note - I am not a mechanic or expert in anything.

 

3 hours ago, Nirrain said:

I have considered it, but from the very thorough analysis done by @RicardoM in Charging diagnostics my understanding is that the start-stop connector should not affect anything else

I'm not so sure as it's part of the very complex interconnected computer programming, I don't see any harm in giving it a go, see the last two paragraphs of one of Breezy_Pete’s posts in that thread.  J367 is Battery monitor control unit with battery sensor.

 

 

https://www.briskoda.net/forums/topic/486431-charging-current/#comment-5463199

 

As I see it your problem, or part of it, could be the current battery possibly weakened or damaged by another issue, the charging system (which includes computer programing) or the computer programming, perhaps an update to it is needed(?).

 

To confirm the battery it would possibly need to be isolated or removed from the vehicle and tested.  The alternator charging could be tested but as one element of the charging system it would need the charging system monitoring.  The computer programs might show a glitch from battery or charging system monitoring if no Recalls or updates are available.

 

The other side of course is the out goings from the battery what is drawn from it, what draws for how much and how long and should it, possibly items added to the car on constant if low drain or going faulty and working when they should not.

 

I think battery monitoring has been covered before and the others have covered VCDS, you could perhaps buy a different system that covers VAG and others makes if later you want to get out of VAG ownership but none of the better systems will be cheap.

 

Unfortunately swapping batteries in and out or around with cars to keep them going whilst testing or charging in another car or "bench" (shed) is not as easy as it once was.  My neighbour has an old spare battery that we move around between his car and van as both are rarely driven so one or the other has the battery too low for when they are used or need moving.

 

5 hours ago, Nirrain said:

Thanks for all the input!

  

 

My "less smart" 2013 Citigo had it original battery last for 9 years with more or less the same usage as the 2018 Octavia with infrequent use, except the citigo was used more for the very short trips. That is why I suspect the newer car being too smart for its own (or at least its battery) good.

 

It was the authorized Skoda mechanic that programmed the new battery when the first battery died after 3 years on the Octavia so I am inclined to believe it was done correctly, though your comment regarding missing the 0 in 70 does raise some suspicion

 

 

I have considered it, but from the very thorough analysis done by @RicardoM in Charging diagnostics my understanding is that the start-stop connector should not affect anything else and to me it seems that the car simply does not charge the battery sufficiently for good health but the start-stop system works as it should as long as the battery is fully charged (when done manually with a corded charger)

 

I have not bought VCDS yet but trying to gauge if this issue would be another argument for getting one - I would also like to change the high beam assist to work at a lower speed but find it hard to pay the price just for that convenience

 

 

That is a very good point, but as I understand the 2018 Octavia does not have regenerative charging and even if the target was 90% shouldn't the BMS still protect the battery from overcharging?

I believe that all micro-hybrids do, in fact, have regenerative charging/recuperation - you may be correct that the BMS will protect the battery from overcharging, but I have not seen any reference of this. I suspect that it might not, otherwise there would have been no real reason for limiting the alternator charging in normal running conditions.    

Please note - I am not a mechanic or expert in anything.

 

As with Warrior193 I have not seen refence to it, and Warrior193 has probably seen a lot more than me about it but on what I have seen so far I suspect the opposite in that as the battery is monitored for the start/stop and the start/stop can be deactivated (or not activated) for various reasons and info from sensors the various computer programming probably has allowances to stop or prevent the battery from being overcharged.

 

Having put that, some of the references I have seen made to some circumstances or conditions for the start/stop to operate or not didn't seem to apply to my wife's car but who knows when the programs are changed or updated from model to model or (part?) year to (part?) year and allowing for programming errors and omissions - as if!, sorry I take that back, such things wouldn't happen. 🙃