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Discussion Starter #1 (Edited)
Over the last month or so I started to notice that the "Stop/Start" isn't as active as it normally is on the same journeys, I just put this down to the system holding off due to engine temp or not enough miles since starting the journey, I don't do a lot of mileage from the house to work.

Anyway, last week I took a spin down to the local shops and when I switched off the engine and opened the door a warning message popped on the screen that said "Low Battery Charge", this is the first time in four and half years since owning the car from new that I've seen this ?

The message came on again when I arrived home and again the following morning, however, it has now stopped appearing over the last 4-5 days, but I've now noticed that the "Stop/Start" is not activating at all, and in the "My Car" menu it says "Stop/Start Not Available" ?
Obviously this is linked to the "Low Battery Charge" warning but if this warning message has now ceased why is the "Stop/Start" still not available ?

I've checked the battery with a multimeter and it shows as 14v with the engine ticking over and 12v with the engine switched off.
I was then thinking that perhaps the battery is not holding it's full charge and maybe I should leave it overnight before checking it on a cold engine, which I've done this morning, but it's still showing 12v !

Apparently there are 2 batteries on the V40 but I can only get access to the main one in the engine compartment, could I be checking the wrong one ?


Any advice appreciated.
Thanks
 

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Had same problem on my D3, same symptoms as yours,have the battery checked at dealers,just using multi meter on battery won't show duff cells in battery,new battery cured mine,any decent auto electric garage could do it,my main dealers are good,they checked and fitted the battery for free,I just paid for battery,was about £170 Inc Vat,I had looked at other prices but weren't much in it,main dealer could check the aux battery as well,it's a small motorcycle type one behind nearside bumper,accesed from under the wheel arch,it's shown in the handbook.12 volts on charged battery is too low.
 

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Discussion Starter #3
Thanks for the reply.
I was hoping that because the "Low Battery Charge" message had gone away so had the "problem", but now that the "Stop/Start" is showing as "Not Available", clearly one of the batteries must be faulty !!

What voltage should a fully charged battery be ?
I read that whilst the engine is running it should be around 13.5v to 14.5v and and cold it should be 12v , is this wrong then ?
 

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Normal fully-charged lead-acid battery should be at least 12.5V when idle, slightly more when in top-notch condition. 12v is pretty much dead.
 

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Discussion Starter #5
Really !
I think you've nailed my problem !
How would I now if its the actual battery not holding a charge or the alternator not putting out enough charge ?
 

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Take the car to main dealers and ask them to check the battery,or auto electrician,they can check for dead cells and charging system.personally I would take it to main dealer's,I know some people avoid them but we have had great service from what is now Shrewsbury Volvo,don't know who is near you ?
 

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Discussion Starter #7 (Edited)
Hi,
Booked in for tomorrow at main dealer (FRF Swansea) it's where I bought the car from.

Out of curiosity I just popped down to Halfords for a free battery check.
The 12 year old "Technician" reckons the car just needs a run up the motorway, this conclusion was made after it took him 10 minutes learning how to turn on the "Top of the range battery tester" that "No other company can afford" , his words not mine, and then running to ask his 13 year old " Technical Service Manager" what all the figures on the screen meant.

I guess you get what you pay for, so in this case the "Free Battery Test" actually cost me 45 minutes of my time !!

Oh, I was informed after explaining that the car had 2 batteries, that the "2nd hidden battery is probably just a spare that can be hooked up if the main one fails, not sure how you'd get the wires to it though" :eek:

At that stage it was time to close the bonnet and for me to go home.
 

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Well there you go then,one of my son's keeps saying take it to any garage it's cheaper rate than volvo,I don't disagree with that,and there are good garages \ mechanics, I do use a local garage for tyres and stuff,but I have found if it takes them twice as long too do the job where as Volvo know the car and what's proberly the fault and have the stock it's as quick and easier to go to them,nothing stopping you getting battery from somewhere else if it's cheaper,but that means more running around and time,my dealer checked fitted it for free,the car monitor's both batteries and that needs to be reset when having new battery,believe it's in the forum somewhere if you want to do it yourself .
 

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My car also suffered from a 'Low Battery Charge' message. It never caused me any problems, cannot say whether or not it affected the Stop/Start as I always turn it off. On the day of my service there was a frost so front / rear windsreen heaters were used, the blower, headlights, heated seats ...
I was advised by the main dealer that the battery charge was low but the battery was testing ok. It was suggested I put the battery on charge, which I did and have not had the message reoccur. It's a 2014 original battery, but the vehicle is not used much. Before I could charge the battery I had to buy the proper charger as the Volvo needs one that is compatible with EFB and AGM batteries. Apparently the ancient one I already had for lead / acid batteries was not suitable.
 
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Discussion Starter #10
I've a feeling that charging the battery might solve this as well ?
It cranks over easily every time, it's just this message appeared (now gone) and the Stop/Start is "Currently Unavailable".
Oddly though when I pulled into the Halfords car park and stopped, the "Stop/Start" actually worked !!
I might invest in a charger if the Volvo dealer cant find anything wrong tomorrow.
 

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My stop\start would work after a long run,the car always started,but with winter coming and it was original battery on a 2013 car just didn't want to be caught out i have a Ctek battery charger which is suitable for AGM battery,I use it mostly on my motorcycle,but usefull on the car.hopefully your sorted tomorrow.
 

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Discussion Starter #12 (Edited)
So bit of an update.
The " Low Battery Charge" message disappeared a few days, and now the "Start/Stop Unavailable" message has now returned to "Available".
I did take the car on a long run this morning !
Therefore I decided not to take the car into the dealers and just see how things go ?

However, I have decided to bin my old (very old) charger and buy one of these "Smart Chargers".
So any tips on what to buy would be great, and also how do you charge these "newer" type batteries ?
I've read conflicting advice on the web about how to attach a charger or jump leads to the negative side of the battery, some advice says under no circumstances should any type of charger or jump leads be attached to the negative side of the battery, especially newer cars with Stop/Start facility, but other advice says a "smart" charger is ok to attach to both sides of the battery ?

This charger caught my attention ?

Any advice appreciated.
Thanks
 

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After a flat AGM battery on my taxi completely blew my old charger, I think the poles can reverse with AGMs when they go completely. I bought a suaoki ics4 from amazon on one of their offers, it works fine with the AGM battery on my V40.
Correct about neg side, I always connect to a bolt on the body near the battery.

BTW I also saw a smart charger in ALDI today, probably reasonable quality .
 

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I have a CTek MXS 5.0 and it works fine. You can use it to charge the battery whilst it is still connected to the car, but you should avoid connecting directly to the negative terminal because it will upset the battery monitoring software on the car and start/stop will be unavailable until the system has recalibrated itself. There is a bolt on a bracket on the nearside strut mount panel adjacent to the battery on my car, but anything that provides a good earth that the charger cable can reach will be fine.
 

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That's the one I use,it can take a couple of days to fully charge the car battery,put mine on over a weekend,it can be left on as long as you like,as above use the stud for the neg cable,I use the clips on the car,and fly lead is permanently wired to my bike so just plug it in,I have the same charger on my mothers car which spends weeks in the garage and it's fine,you might see the warnings come back if battery is on it's way out.
 

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I have a CTek CT5 time to go and permanently attached the provided fly lead. One side to the battery +ve .. the existing bolt that holds the clamp on was long enough to slip the fly lead on and then another nut to hold it. The -ve side I connected to a bolt by the nearside headlamp as this was the correct diameter to fit the connector on the fly lead without modification.
I must admit I find it hard to see what the difference is between connecting to the bodywork as opposed to the -ve terminal as they are both connected together, maybe more resistance this way?
Glad you seem to have sorted your problem jactac!
 
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I must admit I find it hard to see what the difference is between connecting to the bodywork as opposed to the -ve terminal as they are both connected together, maybe more resistance this way?
The battery monitoring system on the car uses a sensor (shunt) connected to the battery negative terminal to monitor current charged or drawn from the battery. This is continuously monitored by the start/stop system and the CEM. If you connect anything, be it a charger or consumer directly to the battery negative post, the current flow bypasses the monitoring shunt and throws the BMS out of synch. The car will realise something is amiss because the voltage and apparent current inflow or outflow don't correspond with its previous calculations and expected relationship, so it will disable systems such as stop/start and smart alternator charging which rely on it. Connecting to an earth on the chassis ensures that current from the connected devices passes from the battery through the shunt on it's route to earth.
 

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Discussion Starter #18 (Edited)
Thanks for the replies and advice.
It looks like the Ctek range of chargers are fairly common for cars with Start/Stop.

I do have one or two other questions, which might be a bit daft to ask !!
As you all know the V40 comes with 2 batteries, the main one in the engine bay and the back up one behind the bumper.
So which one gets charged ?
The main one, the back up one or both ?
Also when the"Low Battery" message appears which battery does this message apply to ?
Does the alternator charge both ?
I've also read on the Volvo site that even though both batteries are 12v, they are actually 2 different types of battery, which needs to be taken into account when charging.


"Important
When replacing the starter battery in cars with the Start/Stop function, a battery of EFB type or stronger must be installed.
When replacing the support battery, a battery of AGM type must be fitted."


I'm a bit cautious about charging the battery(s) on the car because when I first bought the car I jump started my father's car from the V40, connecting the leads straight to the battery, (didn't know at the time about NOT connecting to the negative terminal), a few days later I noticed the sat nav was playing up, the maps were all over the place, anyway I booked the car into the dealers and apparently something had shorted out inside the roof antenna which has something to do with the sat nav ?
It was repaired under warranty, but I can recall the service manager asking at the time if I had disconnected the battery or tried jump starting another car from the V40, obviously I told him the truth and totally denied I had :rolleyes: !

Since then I've been a bit apprehensive when it comes to the car's electrical system.

Once again I appreciate any advice.
 

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Thanks for the replies and advice.
It looks like the Ctek range of chargers are fairly common for cars with Start/Stop.

I do have one or two other questions, which might be a bit daft to ask !!
As you all know the V40 comes with 2 batteries, the main one in the engine bay and the back up one behind the bumper.
So which one gets charged ?
The main one, the back up one or both ?
The main battery. The secondary battery is monitored by the CEM and charged by the alternator when the car is being driven.

Also when the"Low Battery" message appears which battery does this message apply to ?
The main battery. I don't think the car will tell you directly if the secondary battery is low, although I may be wrong. It will be one of the numerous reasons for start/stop being disabled though and AFAIR if you go into the car menu you can bring up an explanation for the reason why start/stop is disabled.

Does the alternator charge both ?
When driving, yes. It's all controlled by the monitoring system.

I've also read on the Volvo site that even though both batteries are 12v, they are actually 2 different types of battery, which needs to be taken into account when charging.
If using a standalone charger, yes. The car takes care of it automatically, although if you replace the man battery with a different type or capacity, you need to update the system via a BMS reset routine using VIDA or other diagnostic software that has that function.

VIDA, and some aftermarket diagnostic equipment (including the android Car Scanner app) can show you the voltage and state of charge of both batteries, as well as diagnostic errors resulting from battery anomalies.

I think manual gearbox cars are fitted with EFB main batteries, and automatics have AGM type. Both have AGM support batteries. The batteries are specially designed to operate at around 80-85% state of charge, because cars with start/stop aim to maintain their batteries in that state to allow capacity for smart alternator charge acceptance under deceleration and braking. You will find that, although a smart charger such as Ctek or similar will fully charge the main battery, the car will very quickly let it return to 80% SOC once the charger is disconnected. One of the reasons why you can very quickly get a low battery warning if you have the ignition on without starting the engine, especially if the radio is switched on, as it doesn't take much of a load without the engine running to drop the voltage and SOC to warning level.

I'm a bit cautious about charging the battery(s) on the car because when I first bought the car I jump started my father's car from the V40, connecting the leads straight to the battery, (didn't know at the time about NOT connecting to the negative terminal), a few days later I noticed the sat nav was playing up, the maps were all over the place, anyway I booked the car into the dealers and apparently something had shorted out inside the roof antenna which has something to do with the sat nav ?
It was repaired under warranty, but I can recall the service manager asking at the time if I had disconnected the battery or tried jump starting another car from the V40, obviously I told him the truth and totally denied I had :rolleyes: !
Well, yes. The reason you shouldn't connect directly to both negative terminals when jump starting is different to the reason when you're using a low capacity "smart" charger though. It's to avoid voltage spikes possibly corrupting or damaging ECUs as you now know ;)
 

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Discussion Starter #20
Great Advice.
I appreciate your time in writing all this (y).
Can I ask is it ok to connect a smart charger direct to the battery (Live & Negative), or just the live and the negative to the chassis/car body ?

Another charger that I was thinking about was the Noco Genius 5 ??
 
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