C5A: New battery with higher capacity? Battery initialization?

[zakazak]

Hi there,
I wonder if a Battery with higher capacity e.g. Yuasa YBX7096 would mean that stop&start would work better?

Additionally I read about the need of initializing the battery by disconnected it, connecting it again and waiting 4 hours. Is this true and when is it required?

Thanks!

[GiveMeABreak]

Always get the best battery you can afford in terms of power. But make sure you replace with the same type as recommended, i.e. anf EFB battery should be replaced with an EFB battery or AGM with an AGM.

Stop Start systems will usually have an EFB battery or an AGM battery. Increasing the Amps means it will have more power and will likely last longer, but some vehicles have a specific battery 'level' configured to the vehicle (usually a level 1 , 2 or 3) depending on the electrical requirements and equipment fitted to the vehicle as well as the engine type. So it is important that the correct level of battery is configured as this can effect the charging and energy management.

Further, depending on your vehicle, you may have the older Stop Start system that uses additional equipment hidden under the front left wheel arch that includes a voltage maintaining device and an ultra-capacitor system used for the Stop Start. Many modern cars have removed all this to save money and instead use a different type of reinforced starter and battery for the system. Mine has such a system but never works as one of the conditions is for the battery to be at least 80% charged, which it never is as I rarely use the car once or twice a week, so it never gets charge back up to this capacity.

So it depends on the system you have, as replacing the standard car battery won't make a bit of difference if you have the older Stop Start system that I talked about, as that is likely to be a failing capacitor.

[zakazak]

Currently I have a Varta 9811722280 which seems to be the OEM version of the Blue Dynamic EFB 570 500 076.
It has 70Ah capacity and 760A cold starting / cranking power.

Replacing it with the Yuasa YBX7096 (also EFB) would change to 75Ah capacity and 700A cold starting / cranking power.
I would understand that capacity is more important for stop-start?

But would that different capacity need a re-programming in diagbox?
Also I wonder why the BSI reset (disconnect battery, reconnecting and leaving it alone for 4 hours) is required / recommended when changing battery?

Last but not least, would you know if my 12/2019 C5A (Shine PureTech 180) would have the additional equipment?

VIN: VR7**************[VIN obfuscated, can be read by forum staff]

[GiveMeABreak]

This vehicle came with a L3 760A 70AH battery and you shouldn't really replace it with one of a lower specification, but Citroen also show a cheaper battery EFB option that has 720A 70AH specs. However the YUASA battery shows in their images for the YBX7096 that it's 720A - when it clearly isn't from the specifications which state only 700AH.

So I would check with YUASA as they are showing one battery with different specs......

I wouldn't go for anything that is less than the minimum requirements though.

Your vehicle is already programmed for a L3 battery type, so needs no configuring.
The BSI Reset / Battery Disconnect / Reconnect Procedure is used to properly shut down the ECUs and networks before disconnecting the battery, to ensure all the data is written back for example and that the networks go to sleep. Follow the procedure to reduce electrical issues and for initialisation of the fobs after battery replacement.

[zakazak]

Thank you for explaining the BSI reset. I was worried that it might also "re-learn" the car batter to the ECU (which I would understand / know what there is to learn).

Regarding YUASA:
The lower parameter is the cold cranking power.
It would depend on how much cranking ampere the engines starter actually needs.
Sometimes this required power is on the sticker which also lists the tire pressure (on the driver side door frame).
No idea if the electrical fuse of the starter would be of any further guidance.
Besides that the battery capacity is actually bigger (75A compared to 70A).

I guess this also means that I do not have the special capacitor?

Does anyone know what the requires min battery volltage for S&S is?

As you recommended, I also asked yuasa via mail.
They didn't really give an answer other than stating that the YBX9096 (AGM Battery) could be a possible alternative as it has 70Ah and 760A.

I also measured the battery voltage with a multi meter:
- Engine off after driving home: 12,87V
- Engine off in the morning before starting the car: 17,75V
- Engine on, right after starting it: 14,40V

Still S&S for whatever reasons suddenly doesn't work anymore (AC off, temperatures in range, ...).

[GiveMeABreak]

As I suspected in your case your C5 Aircross is a Euro 6.2 vehicle, so the threshold for the battery alone for Stop Start to work is 80% minimum.

It is important the calibration by the Battery Charge Status Unit is undertaken by waiting (after battery reconnection to the vehicle) between 4 hours minimum and a full night after the end of the charge of the service battery without touching the vehicle. This is the time required for the charge state of the service battery recorded by the battery charge status unit to change from imprecise > 10% to nominal < 5%).

This is again required if replacing the service battery.

I have the same issue - my Stop Start never works more than a few times after recharging the battery, despite having a new one replaced by warranty only a few years old. As soon as the new battery went in, it worked a few times then stopped again. The batteries are useless for this type of system, but they've done it to reduce costs and not fitting all that previous equipment that was used separately for the Stop Start system operation.

Relying on a standard battery to start the vehicle, power the electrical equipment in the vehicle, and operate the alarm and equipment after the vehicle engine is switched off (like Adblue pump to redact fluid), EGR anti-sticking operation) for example, makes this a non-event to be honest. Who's going to be charging their battery every 2 days just for Stop Start to work? Will cost more to maintain the battery charge than it saves on fuel!

I suspect the same thing will start to happen even if replacing the battery with a different brand / newer one, but I will be interested to see how long it works with Stop Start if you do go ahead with the YUASA/ These are supposed to be good batteries.

[zakazak]

As I suspected in your case your C5 Aircross is a Euro 6.2 vehicle, so the threshold for the battery alone for Stop Start to work is 80% minimum.

It is important the calibration by the Battery Charge Status Unit is undertaken by waiting (after battery reconnection to the vehicle) between 4 hours minimum and a full night after the end of the charge of the service battery without touching the vehicle. This is the time required for the charge state of the service battery recorded by the battery charge status unit to change from imprecise > 10% to nominal < 5%).

This is again required if replacing the service battery.

I have the same issue - my Stop Start never works more than a few times after recharging the battery, despite having a new one replaced by warranty only a few years old. As soon as the new battery went in, it worked a few times then stopped again. The batteries are useless for this type of system, but they've done it to reduce costs and not fitting all that previous equipment that was used separately for the Stop Start system operation.

Relying on a standard battery to start the vehicle, power the electrical equipment in the vehicle, and operate the alarm and equipment after the vehicle engine is switched off (like Adblue pump to redact fluid), EGR anti-sticking operation) for example, makes this a non-event to be honest. Who's going to be charging their battery every 2 days just for Stop Start to work? Will cost more to maintain the battery charge than it saves on fuel!

I suspect the same thing will start to happen even if replacing the battery with a different brand / newer one, but I will be interested to see how long it works with Stop Start if you do go ahead with the YUASA/ These are supposed to be good batteries.

Hmm I wonder how the 80% threshold is being measured. Because in terms of voltage, the battery is at nearly 100%.

Also my S&S initially didn't work for 6 months until I accidentally disconnected the battery for 2 seconds while working on the car.
I then reconnected the battery and since then the S&S has worked for about 1 month. I didn't charge the battery or do anything special to it.
For 3 days now the S&S hasn't been working again. I will try to just disconnect / reconnect the battery again and see if that fixes the issue again.

But I thought there would be a more "logical" way to figuring out what prevents S&S suddenly again.

[GiveMeABreak]

The battery voltage is not the same necessarily as what the battery charge status unit is determining. The battery charge status unit needs calibrating with the new battery attached so it can properly measure what it needs to do to determine the threshold.

You can’t test a battery using a volt meter for this. There’s a procedure where the battery is measured using specialist equipment where the battery has to rest after a period for it to be accurately measured. That’s why when I had my battery replaced under warranty they had to keep the car in overnight for both the charge and for time to disconnect the battery and to take the measurements. Only when they’ve done this, will they get an accurate reading of the battery's performance and be able to replace it under warranty.

[zakazak]

Alright so I did some further digging today with Diagbox and "Launch Creader Elite 2.0 handheld device".
First I used the Launch device to simply read for errors and I also found an option regarding setting the battery type. Originally there was no value so I set it to "sealed VRLA/VRLA2".
Anyway, that didn't fix anything and I couldn't find much more promising options (except also a disabling stop start option).

So I continued with diagbox and found some interesting things.

Here you can see some general information about the battery. The voltage is low and the the battery charge status is at 78% but that is after already standing for 20mins with ignition on and diagnostic tools attached.
What I find interesting is the status of "calibration of wake-up threshold of the battery" and you will see soon why.


Because here is the next screenshot (which I made while the engine was running) and it shows that the battery charge status is invalid and that the estimated voltage for an engine restart is at 10.xxV.
This is absolutely wrong and weird?


Additionally I found an option which lists you the reasons of why stop-start didn't engage during the last 20/40/60km but none of them show any reasons:



And here are just a few more options I found.




Any advice on what to do next? My guess is that there is something wrong with reading the correct battery charge status which is why the car shows an "estimated voltage for next engine restart request of 10V". That will ofcourse prevent stop-start from engaging!

[GiveMeABreak]

Yes, but if you look at the 10.13 V, on your screenshot, it tells you clearly it is ESTIMATED. This means that because it has not had the proper procedure done to calibrate it, it is being estimated - not actual. It's what I was trying to explain to you in my last post, about a new battery being charged, then installed and allowed to rest for 4 hours minimum, but preferably overnight, without any opening of the doors or switching on of equipment - otherwise you will wake up the networks and the calibration will fail.

[zakazak]

Yes, but if you look at the 10.13 V, on your screenshot, it tells you clearly it is ESTIMATED. This means that because it has not had the proper procedure done to calibrate it, it is being estimated - not actual. It's what I was trying to explain to you in my last post, about a new battery being charged, then installed and allowed to rest for 4 hours minimum, but preferably overnight, without any opening of the doors or switching on of equipment - otherwise you will wake up the networks and the calibration will fail.

Hi Marc,

I did that last night. When I started off driving from my office to home, the battery charge status was at 93%. So I imagine that when arriving at home, the battery charge status was even higher (highway, no stop-start engaged at all). I turned off the engine, closed the doors, waited 5 minutes and then disconnected the battery (red "+" cable) for a few seconds. Then I re-connected the battery and let it sit over night.

This morning stop-start was still not working.

In the mean time I also figured out that installing an AGM battery is possible when switching the battery type from "reinforced cyclable fluid" to "Sealed VRLA/VRLA2".
For example Yuasa YBX9096 would fit well then.
The AGM battery should have the potential to be better but in my case it seems like the installed EFB battery is just healthy and fine as well.

[zakazak]

So I drove the car to get the battery charged. I disconnected the battery, waiting 15mins without the keyless dongle beating anywhere near, reconnected the battery and waited 14 hours.
I then drove for 1 hour and waited another 14 hours.
Then I made the following screenshots from diagbox.

The battery seems to be fine although the "estimated voltage on next engine restart" is still ridiculous low.