Advice on dispute with used car dealer

[vaud]

the-norseman said:

vaud said:

It has all the symptoms of needing a new battery...

Agreed we had similar issues on our Volvo turned out it was just a duff battery.

My Jag is throwing all sorts of random things recently and I've been advised it is the battery, which is hardly surprising after 8 years.

[OutInTheShed]

StuTheGrouch said:

I would change the battery. Do Astras of this era need the battery to be coded to the car, like BMWs do? I've had a faulty battery on a BMW before and there were all sorts of funky faults going on, all cleared by changing the battery.

Some BMW's don't need the batter coding to the car.

If you replace the battery, it just throws up an error light the first couple of times you drive it, then it's happy.

Some cars can benefit from disconnecting the battery and reconnecting it after a while. A total reset of the ECU etc.
Other cars, that's just a PITA because the radio will need coding and you won't be able to open the boot to put the battery back in....

Unless people know the preculiarites of the exact model and software release, or have read the factory manual, they are just guessing.

If you've driven some modern cars with a voltmeter plugged in, you might be aware that many modern cars faff with the charging and don't always leave the battery fully charged. Playing games with the alternator, deciding when to charge the battery, can help mpg and co2 ratings, possibly other emissions too.
It may be time to realise that an understanding of battery/alternator systems based on growing up with Cortinas is outdated!

[T0MMY]

OutInTheShed said:

It may be time to realise that an understanding of battery/alternator systems based on growing up with Cortinas is outdated!

I think I'm starting to realise that, having spent many years running unreliable kitcars for trackdays I thought I knew a bit about fixing cars but all this stuff is news to me.

Anyway, I tried disconnecting the battery and the voltage jumped up about 0.2V to 12.2 or so. I'll try charging it and report back.

If it really does just need a new battery I'd be overjoyed, even though these start/stop ones are about 3 times as much as the last car battery I had to buy.

Incidentally I started the car just now and it's still seemingly fine, starts and runs perfectly, no warning lights. I didn't actually drive it but no doubt it'll be ok, right up until it isn't again.

Edited by T0MMY on Wednesday 28th February 16:24

[StuTheGrouch]

OutInTheShed said:

Some BMW's don't need the batter coding to the car.

If you replace the battery, it just throws up an error light the first couple of times you drive it, then it's happy.

I'd like to say I only did it because I do things properly, but the reality is the BMW specialist was able to source a battery cheaper than I could and the cost of recoding it was not much extra. It was eye-wateringly expensive compared to the last battery I changed either way.

My current BMW has stop/start. I hope that doesn't need a new battery any time soon.

[OutInTheShed]

StuTheGrouch said:

I'd like to say I only did it because I do things properly, but the reality is the BMW specialist was able to source a battery cheaper than I could and the cost of recoding it was not much extra. It was eye-wateringly expensive compared to the last battery I changed either way.

My current BMW has stop/start. I hope that doesn't need a new battery any time soon.

I think some of the 'stop/start' batteries have come down in price?
You do have to be careful, all 'lead-acid' batteries are not the same, there re various flavours with added calcium, carbon, AGM and god-knows what.
Some have slightly different voltages, so the car may need coding to the correct profile.

The good news is that with these higher tech alternator set-ups, batteries seem to commonly last a very long time.
The last one I changed was about 9 years old, on a stop/start Honda. The old battery was down to something like 20% capacity, but the car was still starting OK! That's could be related to starter motors having improved since 'ye olde days'?
I think I spend more on motorbike batteries.

[rallycross]

Try a new battery then get a decent auto elec to have a look if still have the problem won’t cost much and easy way to sort it ( most likely but not guaranteed).

[lord trumpton]

It sounds like a problem with the thingymabob to be honest.

I'd suggest connecting a wotsit to the bit in the middle and see if you can smell anything.

Report back OP...

[Griffith4ever]

OutInTheShed said:

I think some of the 'stop/start' batteries have come down in price?
You do have to be careful, all 'lead-acid' batteries are not the same, there re various flavours with added calcium, carbon, AGM and god-knows what.
Some have slightly different voltages, so the car may need coding to the correct profile.

All the "coding" does is tell the ECU what AH (capacity) your battery has, so it has a headsteart on how it can handle stop start (i,.e., how low a voltage it will allow it before it disables stop start). Nothing more complicated than that. Its mostly a con as capacity makes little difference. 12.2 v on a 120Ah battery is the same as 12.2v on an 85 AH battery..... only real difference is a larger AH battery has more ability to recover.

Charging profiles are the same - the difference between AGM and non AGM is about 0.2v, and not critical. The main types are flooded lead acid and AGM (which is lead acid with glass matting). Calcium added lead acid batteries basically last longer, for more money. Charging profile is the same.

All this "coding" stuff with batteries is rediculous. They whack a bar code on your battery - that's it. There are no chips or other magic items. Using your dash computer to enter "100 AH" would achieve exactly the same. But that would not allow dealerships to charge extra for fitting a battery....

[NRG1976]

Griffith4ever said:

OutInTheShed said:

I think some of the 'stop/start' batteries have come down in price?
You do have to be careful, all 'lead-acid' batteries are not the same, there re various flavours with added calcium, carbon, AGM and god-knows what.
Some have slightly different voltages, so the car may need coding to the correct profile.

All the "coding" does is tell the ECU what AH (capacity) your battery has, so it has a headsteart on how it can handle stop start (i,.e., how low a voltage it will allow it before it disables stop start). Nothing more complicated than that. Its mostly a con as capacity makes little difference. 12.2 v on a 120Ah battery is the same as 12.2v on an 85 AH battery..... only real difference is a larger AH battery has more ability to recover.

Charging profiles are the same - the difference between AGM and non AGM is about 0.2v, and not critical. The main types are flooded lead acid and AGM (which is lead acid with glass matting). Calcium added lead acid batteries basically last longer, for more money. Charging profile is the same.

All this "coding" stuff with batteries is rediculous. They whack a bar code on your battery - that's it. There are no chips or other magic items. Using your dash computer to enter "100 AH" would achieve exactly the same. But that would not allow dealerships to charge extra for fitting a battery....

That isn’t correct, for example copy and paste from a different website :


The downside of not resetting the BMS system is that the life span of the replacement battery may be shortened as they are sensitive to being overcharged. If the BMS thinks the battery is aged, it will charge it for longer periods than necessary. While you may save a buck by not paying the additional cost to register your replacement battery, you will likely loose in the long run. Another replacement battery may be required sooner if you do not complete the battery registration properly.

[OutInTheShed]

at the end of a the day, a battery is about a hundred quid, you don't get much main dealer faffing for that, so there's a case for just buying a battery and kicking the problem down the road, even if it's not optimum.

If that won't work for your particular car, then you may need specific advice.

[GasEngineer]

T0MMY said:

here's a more complete timeline: ......

Feel a bit foolish / waste of time offering you advice OP when you had already done all this without telling us in your OP.

Most people are telling you its the battery. Either tell the selling dealer or get one fitted yourself to save hassle to fix the issue or eliminate it as the cause.

[Griffith4ever]

NRG1976 said:

That isn’t correct, for example copy and paste from a different website :


The downside of not resetting the BMS system is that the life span of the replacement battery may be shortened as they are sensitive to being overcharged. If the BMS thinks the battery is aged, it will charge it for longer periods than necessary. While you may save a buck by not paying the additional cost to register your replacement battery, you will likely loose in the long run. Another replacement battery may be required sooner if you do not complete the battery registration properly.

Twaddle. A battery is a battery. Telling the car your battery is new makes no odds, and even if it did, why can't it be done through the dash ? "Menu, settings, battery replaced, confirm". I wonder....

That copy and paste is guff to justify it. ALL batteries are sensitive to being overcharged. You don't charge a new battery for shorter times and old ones longer, you charge them until the voltage tells you they are full, it is as simple as that. When they are full you back off to a maintenance charge (unless lithium then you stop completely ). Or, if it's a "smart alternator" like on VW blue motion vehicles, it lets the battery drop to 80% (based purely on voltage, there is no other way) to allow for regen braking.

Lead acid batteries charge to a set voltage (to 100% full) , and then require a gentle top off as they lose charge naturally over time. Lithium batteries charge to a set voltage and are left there - they like to be stored long term at around 80% capacity. The age of the battery does not infulence the charging method.

I work in this field.

There has been no magic change in lead acid batteries or their charging that has brought in the need for "coding". Its a con to stop you dropping into Halfords or buying for half the price at Tayna.

Edited by Griffith4ever on Thursday 29th February 09:41

[Unreal]

My experience with batteries is that they only need to be a bit off peak performance to start throwing faults.

Sometimes the drain on starting the car, especially if has stood for a few days, can throw a fault on a start up component like ABS or an airbag. Those components call for a certain amount of power and if it's only slightly down due to the load on the battery then the fault may appear. It will then stay showing a fault until cleared.

Some of the figures being bandied about for a resting battery 12.3-12.4V would concern me. I'd expect high twelves and a minimum of 12.7 for a healthy resting battery. Charging at 14 or so is more a test of the alternator not the battery.

OP - you have been given good advice. Get a code reader and clear the codes. Fit a new fully charged battery. See what happens. Take it from there.

[OutInTheShed]

Unreal said:

.....

Some of the figures being bandied about for a resting battery 12.3-12.4V would concern me. I'd expect high twelves and a minimum of 12.7 for a healthy resting battery. .......
...

I think if you went around a selection of healthy modern cars with a voltmeter, you might find quite a few of them resting well below 12.7V

That's if you can find a car that's actually resting, mostly they wake up and draw a jolt of current to open the door before you can poke them with a meter...

[Unreal]

OutInTheShed said:

Unreal said:

.....

Some of the figures being bandied about for a resting battery 12.3-12.4V would concern me. I'd expect high twelves and a minimum of 12.7 for a healthy resting battery. .......
...

I think if you went around a selection of healthy modern cars with a voltmeter, you might find quite a few of them resting well below 12.7V

That's if you can find a car that's actually resting, mostly they wake up and draw a jolt of current to open the door before you can poke them with a meter...

That may be but perhaps those cars aren't exhibiting a range of faults that a number of people have highlighted can be associated with battery issues. This one is.

For reference:

https://carbatterygeek.co.uk/car-battery-voltage-c...

[OutInTheShed]

Griffith4ever said:

Twaddle. A battery is a battery. Telling the car your battery is new makes no odds, and even if it did, why can't it be done through the dash ? "Menu, settings, battery replaced, confirm". I wonder....

That copy and paste is guff to justify it. ALL batteries are sensitive to being overcharged. You don't charge a new battery for shorter times and old ones longer, you charge them until the voltage tells you they are full, it is as simple as that. When they are full you back off to a maintenance charge (unless lithium then you stop completely ). Or, if it's a "smart alternator" like on VW blue motion vehicles, it lets the battery drop to 80% (based purely on voltage, there is no other way) to allow for regen braking.

Lead acid batteries charge to a set voltage (to 100% full) , and then require a gentle top off as they lose charge naturally over time. Lithium batteries charge to a set voltage and are left there - they like to be stored long term at around 80% capacity. The age of the battery does not infulence the charging method.

I work in this field.

There has been no magic change in lead acid batteries or their charging that has brought in the need for "coding". Its a con to stop you dropping into Halfords or buying for half the price at Tayna.

Edited by Griffith4ever on Thursday 29th February 09:41

I think there have been some changes to battery systems in cars.
It's not 'magic' it's mostly software written by people who need a slap.

There have been subtle improvements and variations in Lead-Acid chemistry, improving battery life, reducing water loss.
Charging systems used to be an alternator set to 14.4V This is a good average voltage to use when a car is used for 1 to 3 hours a day, but tends to result in overcharging in heavily used car.
A 'modern' charging system has a current sensor at the battery terminal and gives the battery what it needs, while also choosing when to charge, ranging from boosting the charge during engine braking, through to diesel-gate style manipulation.
These systems 'notice' changes in the battery characteristics. A sudden change might be the battery has been changed, or it might be the battery is about to fail and that could be catastrophic.

Because the software is generally poor and not 'customer focussed', it's not likely to give a message saying "buy new battery from Tayna and press Reset", it will give random errors implying 'have car and wallet towed to main dealer'.

[T0MMY]

GasEngineer said:

Feel a bit foolish / waste of time offering you advice OP when you had already done all this without telling us in your OP.

Most people are telling you its the battery. Either tell the selling dealer or get one fitted yourself to save hassle to fix the issue or eliminate it as the cause.

Apologies for that, the purpose of the thread was originally supposed to be more about the dispute side of it than diagnosing the issue hence not going into as much detail originally. I'm really not ignoring the advice that the battery could be the cause but if I'm honest, were it not for bizarre electrical faults, nothing would actually indicate the battery is struggling in as much as it never struggles to turn the starter motor, it never disables the start/stop or throws up any battery warnings, the Kwik Fit battery tester showed the battery was fine and when we have had the issues with the car it's as likely to have been after it's just been driven on a long journey as when it's been sat for a week or more in the cold. I definitely will try a new battery eventually though but I'd like to eliminate any easy/free things first.

To that end, I used the car for work today which involved visiting several sites, multiple stops and starts etc. The car was fine all day (actually I quite enjoy driving it!) apart from at one point when I put it in reverse and it threw up the warning lights and messages and went into limp mode. That got me wondering about the parking sensors which are aftermarket and thus slightly bodged. I've disconnected the power supply to them and haven't had the faults since although that doesn't mean much at this stage, especially as before I did so I'd tried replicating it by reversing again multiple times without a reoccurence. I'll keep using the car for at least the next few weeks and see what happens.

Edited by T0MMY on Thursday 29th February 22:03

[Unreal]

T0MMY said:

GasEngineer said:

Feel a bit foolish / waste of time offering you advice OP when you had already done all this without telling us in your OP.

Most people are telling you its the battery. Either tell the selling dealer or get one fitted yourself to save hassle to fix the issue or eliminate it as the cause.

Apologies for that, the purpose of the thread was originally supposed to be more about the dispute side of it than diagnosing the issue hence not going into as much detail originally. I'm really not ignoring the advice that the battery could be the cause but if I'm honest, were it not for bizarre electrical faults, nothing would actually indicate the battery is struggling in as much as it never struggles to turn the starter motor, it never disables the start/stop or throws up any battery warnings, the Kwik Fit battery tester showed the battery was fine and when we have had the issues with the car it's as likely to have been after it's just been driven on a long journey as when it's been sat for a week or more in the cold. I definitely will try a new battery eventually though but I'd like to eliminate any easy/free things first.

To that end, I used the car for work today which involved visiting several sites, multiple stops and starts etc. The car was fine all day (actually I quite enjoy driving it!) apart from at one point when I put it in reverse and it threw up the warning lights and messages and went into limp mode. That got me wondering about the parking sensors which are aftermarket and thus slightly bodged. I've disconnected the power supply to them and haven't had the faults since although that doesn't mean much at this stage, especially as before I did so I'd tried replicating it by reversing again multiple times without a reoccurence. I'll keep using the car for at least the next few weeks and see what happens.

Edited by T0MMY on Thursday 29th February 22:03

A battery can be failing or the source of weird problems and remain capable of starting the car so I wouldn't take starting as a guarantee it's ok.

The other issues I'd consider would be water ingress - either to a fuse box or a multi-connector. Might be worth checking any of those that are easy to see - probably under the bonnet.

[poo at Paul's]

T0MMY said:

My partner bought a car from a very well known online car seller about 5 months ago which has now started intermittently throwing up various electrical faults (spurious warning lights, going into limp mode, tachometer going haywire, failing to start, etc.).

She only got a 90 day warranty but obviously CRA 2015 states that within 6 months of purchase the fault is assumed to have been there at the point of sale unless the seller can prove otherwise. So the onus is on the seller to provide this proof but what does one do when you don't agree with their proof?

The dealer has stated that as the car was (apparently) showing no diagnostic fault codes when sold and had passed all of their other pre-sale checks then that constitutes evidence the fault didn't exist at the time. As such they are now basically ignoring us completely, not returning calls or replying to emails.

What defines "proof" in this situation? There were various other faults with the car in the first few months which were evidently also not picked up and which they did acknowledge existed so clearly their checks are fallible.

why not say what car it is? Maybe someone will know what the cause is, you say later at youve been told it is common ecu fault. IME, there is no such thing, ECUS very robust. But you do get issues if they get wet etc, eg passats and their BCMs.
Tell us the car and get some advice on fixing it i reckon.

[poo at Paul's]

Stick a battery on it, a good one Bosch Silver from EuroCar parts, something like that, 5 year warranty.

If it doesnt sort it, it will do no harm and is only a ton or so. Dont mess with cheap batteries, get bosch or vartas. And euro will change it under warranty, i have had two on a little used ducato under warranty, no messing at ECP.

I's also check all the under bonnet fuse and relay boxes for any water ingress or corrosion, and also go over them and "seat" all the fuses and particularly relays to make sure non are loose.

We had an audi with a turning over but not firing issue, a diesel, and it was a relay in the end, 18 quid from audi. Also Porsche DME relays are carried by most savvy Porcshe drivers as spares in the glovebox! Turns many a complete basket case car into a german perfection all for about 9 quid!