Start Stop Battery Replacement

[WelshRobin]

I raised this matter of the faulty support battery at the third service - like Bekster just before the end of the warranty. The dealer said the support battery was good but the main battery voltage was low because of low mileage in recent months. I’m not convinced.

[zjhiie]

Hi,
I had the usual symptoms of failed start stop battery when just out of warranty which is frustrating
I wanted to replace it myself but could find nothing on web to say how to gain access to the battery or video of replacement on XC40.
I knew that it is low down at front NS, and eventually found that access is by removing NS front wheel and removing screws for front half of wheel arch liner. (5 torx and 2 10mm hex)
Have replaced with Yuasa of identical electrical and physical specifications but found that the terminals of volvo battery are screwed bolts and standard battery has bolt and captive nut approach.
The volvo battery is therefore an OEM special due to the terminal arrangement.
The negative connector will not fit on standard battery with captive nut approach in the orientation volvo designed, however it will fit if rotated 90 degrees anticlockwise when viewed from above.
To do that I needed to cut back the sheathing around the two wires to extend the separate wire lengths.
So I got there in the end paying £45 for battery at Halfords and not dealer cost of £167.40.
The connections are not marked (which is poor) but once the sheathing is cut back a red wire is exposed (positive).
Old battery was under 11V, so had failed.
On restart with new battery all error messages are gone.
Hope this helps others - it would be good to have a youtube video of this, can't be long before someone obliges.
Having figured it out, the job will be under 1 hour when I have to do it again in 3 more years.
Photo of finished job attached.
Also a photo of the Volvo original borrowed from ebay scrap dealer!

Hi Jonathan, many thanks for your post! just would like to ask: the battery you have replaced is the one "The 12 V support battery is located down in the engine compartment", which is the one under the High beam light?

I found this picture from volvo website but still not sure which one should I change, my car has the same message: "start/stop not working", and also "park assist not working". Thanks a lot!

[jonathan66]

Hi,
yes - you are correct.
The start/stop support battery is the one located "down in the engine compartment".
If you read my post, you will learn that the access is obtained by removing the wheel and wheel arch liner.
Jonathan.

[zjhiie]

Hi,
yes - you are correct.
The start/stop support battery is the one located "down in the engine compartment".
If you read my post, you will learn that the access is obtained by removing the wheel and wheel arch liner.
Jonathan.

Thanks a lot Jonathan!

[eng59]

I finally got round to fitting a new battery today,all the tips before in the topic are relevant and here’s my input
1. Do take out the whole plastic cover,it will make life so much easier when doing the work.
2, Torx screwdriver and 8mm/10mm sockets needed to remove cover and battery/leads
3. I did trim about 1/2” of the wrap around cables to allow flexibility
4. The replacement battery (yusua) fitted perfectly and kept the cables in same position,using the nuts/ captive nuts that comes with new battery ( the battery cost £51)
5. You can rest the battery on the shelf that’s inside the wing,so connecting battery is easier than trying to hold and fir wires
6. Took around 1.5 hrs as I took my time
7. Started car and reverse alerts now work as well as stop/start sign now disappearing when other drive modes selected
8. Old battery showed 10.42v when out of car .

[Felindre]

What a nightmare! I'm glad they've changed it for the mild hybrid, regular full size 12v battery up front, and 48v starting battery (also full size) now in the spare wheel well in the boot.

[Steve H]

Hello.
I need some help please. I've got the stop start battery maintenance req on my dash. I've changed the auxiliary battery to a new Yuasa YTX12. But upon pulling away after the replacement the fault sign still appears. Do I have to disconnect the main battery at the same time as replacing the aux battery? Or is there a way to get rid of the message ony dash. Many thanks in advance.
S.

[Steve H]

Quick update. After I replaced the battery the fault light was still on dash. Left it overnight & fault now gone!!. Car must have needed to shutdown for a while to reset. Result!!

[Mooonte]

Hello,

I'm new in the forum, first post. I found very good info in this thread, thanks to all of you!

I got the "Start stop auxiliary battery service required popup" since more than a week.
Yesterday I used a 12v charger connected to the main battery but the fault didn't go away.
Today I got access to the auxiliary battery and measured the voltage after disconnecting the negative pole: 12,6V. But the pop up still shows up.

Any idea if there's a way to force the system to readout the new value? Maybe putting in a forced standby/hibernate mode? Or is the only way to clear it out with Vida?
Or could it be that the battery is holding charge (and therefore the 12,6v) but it has degraded when it comes to current draw/voltage drop, and that still keeps the fault active?

Thanks in advance!

[jonathan66]

Hi,
I could not find a way to isolate measure the start/stop battery voltage from within the engine compartment.
I believe that any measurement made from within the engine compartment will be false.
The only way I found to measure the voltage is directly at the start/start stop battery with one terminal removed.
To do that you will need to remove the wheel and wheel arch liner.
Have you done that?
Jonathan.