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Discussion Starter #1
Hi all,

Purchased a 2018 V40 T2 R-design in early March, and since taking ownership it’s been clear some sort of battery/alternator fault has been developing.

Around a week after purchase the auto stop/start begins working only intermittently, week after it stops completely (MY CAR shows that battery charge is too low or battery not up to temp), then before setting off on a long journey I get a low battery warning - no problem I think, it’ll charge on the drive.

The journey itself was maybe a week or two ago, and things seemed to be fine.

Had to travel again today (for food shopping during our lockdown) and get the low battery warning again.

I’m just wondering if anyone could advise on what course of action I should take here RE: contacting Volvo or the dealership, or some kind of repair under warranty.

Car was purchased at a UK dealership - I know things may be a little tricky with Covid-19, but I’m unsure who to contact for an issue like this so soon after getting the car.

Thanks all, hope everyone is staying safe!
 

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How much or little have you been using it, apart from the long journey? Modern cars with start/stop "start" at a disadvantage in that the system which controls the battery charging maintains it at 80% state of charge, to allow reserve capacity to absorb smart alternator charging under deceleratioin and braking.

So the car sits at 4/5ths charged and with a small but not insignificant battery drain from the onboard ECUs, which still draw some power, even in sleep mode (parked and locked car).

I find that if I leave my car parked and unused for a couple of weeks it benefits from a battery charge, although not critically low, but 4 weeks is pushing it.

Additionally, if you are only using it for short trips every few days or once a week say, bearing in mind the current lockdown situation, starting the engine is going to take power from the battery which it may not be able to fully replenish in a journey of only a few miles, so you may actually be taking more out of the battery than is being put back in, especially if you have things like auto-climate and the multimedia system on.

If it is sitting for several days at a time and only going to your nearest food shop and back, I would say there's nothing wrong with the car, but you would benefit from using a smart (microprocesser controlled) charger such as a Ctek or Accumate type, eithger left permanently connected between trips or just to give it a boost charge once every couple of weeks.

Normally I do the latter as a matter of course, as my car can sometimes be parked for 2-3 weeks at a time. In the current situation however, I have left it permanently connected to a Ctek charger in motorcycle mode, to supply a continuous low trickle charge for 7 days, and then monitor and charge automatically as detected by the charger.
 

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How much or little have you been using it, apart from the long journey? Modern cars with start/stop "start" at a disadvantage in that the system which controls the battery charging maintains it at 80% state of charge, to allow reserve capacity to absorb smart alternator charging under deceleratioin and braking.

So the car sits at 4/5ths charged and with a small but not insignificant battery drain from the onboard ECUs, which still draw some power, even in sleep mode (parked and locked car).

I find that if I leave my car parked and unused for a couple of weeks it benefits from a battery charge, although not critically low, but 4 weeks is pushing it.

Additionally, if you are only using it for short trips every few days or once a week say, bearing in mind the current lockdown situation, starting the engine is going to take power from the battery which it may not be able to fully replenish in a journey of only a few miles, so you may actually be taking more out of the battery than is being put back in, especially if you have things like auto-climate and the multimedia system on.

If it is sitting for several days at a time and only going to your nearest food shop and back, I would say there's nothing wrong with the car, but you would benefit from using a smart (microprocesser controlled) charger such as a Ctek or Accumate type, eithger left permanently connected between trips or just to give it a boost charge once every couple of weeks.

Normally I do the latter as a matter of course, as my car can sometimes be parked for 2-3 weeks at a time. In the current situation however, I have left it permanently connected to a Ctek charger in motorcycle mode, to supply a continuous low trickle charge for 7 days, and then monitor and charge automatically as detected by the charger.
Good idea on leaving ctek charger on motorcycle mode.
 

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Where are the recommended charging connections and do you have to disconnect the battery from the car?
 

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I had the same problem with low battery notification recently. Car has stood still for a week. I couldn't open the doors and the car wouldn't start. I started the car with the starter cable and is now good again after driving for a while. I have another persistent message now: Volvo on Call service required. Maybe it's the backup battery, because they used when the battery is completely empty and is not rechargeable. I am going to try ELM327 with VIDA to read or reset the notification if its possible. I have no Dice.
Also I have read that the VOC battery is built into the system so not something you can access. It is possible that it’s caused by being stood for a while.


I am also looking for a solution
 

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Where are the recommended charging connections and do you have to disconnect the battery from the car?
No need to disconnect if using a smart charger with limited current capacity. If using an old style bulk charger, then it would be prudent to do so.

Connect the charger positive lead to the battery positive terminal, and the charger negative to any suitable earth point of the chassis. There's a small earth lead connected to a bolt on the nearside strut mount turret near to the battery on my car - I use that.

Connecting the earth direct to the battery terminal bypasses the shunt for the battery monitoring system and confuses the BMS, disabling the start/stop system. In can be recovered by parking the car with all doors shut and locked for 6 - 8 hours, but it's extra hassle that's easily avoided and not connecting directly to the battery negative terminal also avoids a very slight risk of corruption or damage to ECUs due to voltage spikes.
 

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Discussion Starter #7
Thanks all - I’ll monitor the situation, maybe drive with the climate controls and multimedia off during the current Covid-19 restrictions!

I’ll try to give the car some longer runs for work/shopping too, and if it persists I’ll look into a charger, although I live in a flat/apartment so slow charging may be tricky!

If all else fails I’ll ask the aftersales team at the dealership know and maybe get the battery checked.

Cheers
 

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Would the system tolerate disconnecting the main battery terminal completely for a long period? Thus avoiding any drain.
I always do that with other older vehicles but I have never dared to unhook my V40 battery.
 

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Would the system tolerate disconnecting the main battery terminal completely for a long period? Thus avoiding any drain.
I always do that with other older vehicles but I have never dared to unhook my V40 battery.
I'm sure it would, but you'd lose the adaptations learnt by various ECUs and they'd have to start again from scratch. There's also a very minor risk every time a battery is disconnected and connected of damaging or corrupting ECU memories, so I feel it's something best avoided unless absolutely necessary for maintenance work or changing a battery.
 

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I'm sure it would, but you'd lose the adaptations learnt by various ECUs and they'd have to start again from scratch. There's also a very minor risk every time a battery is disconnected and connected of damaging or corrupting ECU memories, so I feel it's something best avoided unless absolutely necessary for maintenance work or changing a battery.
Ok thanks. last resort then.
 
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