Stop Start function and trickle charging

Faults and Technical chat for the Volvo XC40
Rifleman
Posts: 435
Joined: Wed Mar 21, 2018 2:21 pm
Location: Nottingham, UK

Post by Rifleman »

Wedgie wrote: Wed Mar 31, 2021 6:26 pm Had an interesting discovery today. I have been using a CTEK MXS 5.0 trickle changer on the car since new but the battery has never seemed fully charged and the stop start rarely functioned , perhaps not surprising given the lack of use due to Covid. I needed a second trickle charger for my motorbike and decided to use the MXS 5.0 on the bike and bought a new MXS 10 to use on the XC40. The battery is 70Ah in the XC40 and the MXS 5.0 is rated at 14-160Ah so should be fine. The MXS10 is rated at 20-300Ah . After 24 hours on the MXS 10 the car was showing fully charged and the stop start worked even after several short journeys and several starts.
I bought a CTEK MXS 5.0 a few weeks ago in an attempt to fix my non-working stop/start. Left the car on trickle charge for 48hrs. Stop/start worked again first journey and continued to work for the next few trips, each with no more than 1 to 2 days standing on the drive between trips. Then left the car on the drive for 7 days before next trip. Stop/start no longer worked.
It’s back on the trickle charger now...
XC40 | First Edition | 2.0 D4 AWD | Bursting Blue | 19" wheels | Ordered 11/03/18 | Delivered 19th October 2018.

Rollo
Posts: 5
Joined: Thu Apr 01, 2021 7:40 am

Post by Rollo »

I wonder if the carbon footprint/emmisions at the power station generating the electricity to supply the trickle charger, and the factory that made the trickle charger cancels out the pollution generated at the car end when the stop/start system is inoperative 🙂. Makes you think!!
WelshRobin
Posts: 161
Joined: Wed Jan 08, 2020 8:55 pm
Location: Norfolk

Post by WelshRobin »

With only low mileages my stop/start had not worked for several weeks. Early this week I did a 50 mile trip and the next day the stop/start function worked, as I expected. But today, after a couple of short hops and about 8 miles total, it is back to the not working condition again. I’m not too bothered because it is not a setting I generally use but I understand the auxiliary battery has other uses so it needs to be functional.
Felindre
Posts: 777
Joined: Wed Dec 23, 2020 2:19 pm
Location: South Wales, UK

Post by Felindre »

blastpipe wrote: Thu Apr 01, 2021 9:56 am Is there a difference between the T/D models and the newer B models with regards to batteries and stop start functionality?
Yes, the alternator and 'starter motor' is now a larger motor/generator belt driven off the side of the engine, and connected to a 48 v battery (in the boot). So it's this 48 v battery and motor that starts the car. I'm guessing therefore they've switched to ancilliaries running off the regular 12 v battery.

Starting's amazing, not the usual noise, almost totally silent.

I'll have to have a nose, see if this us the only generator, and it's stepped down to cover the 12v battery.

I would also say with this new system SS has worked faultlessly since i've had it.
B4 AWD Inscription , Fusion Red, Blond interior. Drivers Assist, Climate, Tinted rear windows and Towing pack.
Ordered 14 Dec 20, delivered 10 March 21
blastpipe
Posts: 565
Joined: Tue Aug 28, 2018 9:04 pm
Location: UK

Post by blastpipe »

Felindre wrote: Fri Apr 02, 2021 9:35 am
blastpipe wrote: Thu Apr 01, 2021 9:56 am Is there a difference between the T/D models and the newer B models with regards to batteries and stop start functionality?
Yes, the alternator and 'starter motor' is now a larger motor/generator belt driven off the side of the engine, and connected to a 48 v battery (in the boot). So it's this 48 v battery and motor that starts the car. I'm guessing therefore they've switched to ancilliaries running off the regular 12 v battery.

Starting's amazing, not the usual noise, almost totally silent.

I'll have to have a nose, see if this us the only generator, and it's stepped down to cover the 12v battery.

I would also say with this new system SS has worked faultlessly since i've had it.
Thanks - that's helpful. Corrects some of the earlier posts in this thread which really only apply to the B versions and not P/D versions.
T4 Auto AWD R Design March 2019
Deleted User 3359

Post by Deleted User 3359 »

Also, the 12v is charged by a Battery to battery charger...
Felindre
Posts: 777
Joined: Wed Dec 23, 2020 2:19 pm
Location: South Wales, UK

Post by Felindre »

Cornishman wrote: Fri Apr 02, 2021 3:58 pm Also, the 12v is charged by a Battery to battery charger...
That's interesting to know, guess it would have to be if the motor/generator is putting out 48 v.
B4 AWD Inscription , Fusion Red, Blond interior. Drivers Assist, Climate, Tinted rear windows and Towing pack.
Ordered 14 Dec 20, delivered 10 March 21
dnyoung607
Posts: 12
Joined: Wed Apr 01, 2020 2:03 pm

Post by dnyoung607 »

stop/start on my 2019 XC40 T5 has not worked in over a year... of course COVID cut driving way down. But now I am driving more again and still does not function. Dealer has offered no assistance; say battery is charged!! (member from USA)
eugen61
Posts: 1211
Joined: Sun May 10, 2020 7:33 am

Post by eugen61 »

dnyoung607 wrote: Thu May 06, 2021 7:57 pm stop/start on my 2019 XC40 T5 has not worked in over a year... of course COVID cut driving way down. But now I am driving more again and still does not function. Dealer has offered no assistance; say battery is charged!! (member from USA)
When was the last time your car got a system software update at your dealer’s service? Latest software patches seam to have ironed out the start-stop function bug.
Deleted User 3491

Post by Deleted User 3491 »

The stop/start function not activating due to lack of driving is not a bug, it's physics.

Don't drive very much? Then the stop/start system won't activate. It's working, just not activating.

Drive more - it will start to activate.
Post Reply