Car battery MK8

[cjay1]

096 AGM is what I have now this is 15 mm higher than the original battery so I had to adjust the top bracket to make it fit. And to allow the car to take advantage of the faster charge aceptence and higher capacity you need to tell the car it has a h7 AGM 70ah battery fitted.

[Scorpion993]

1 minute ago, Eric Bloodaxe said:

Lol all this is making me think if/when I need a new battery I'm just gonna let the dealer do it!

It took me a month to decipher everything ahaha, I learned so many things, and I bought two battery because the first one was tall 175cm lol. Fortunately I've got the refund.

I like to do car things on my own, at least, simple thing such as changing battery, but yeah...Fiesta MK8 battery isn't very user friendly is you don't know anything about the situation. I guess it's easier to change the battery than pick the right one ahah. 

Changing battery requires to remove the airbox (not totally) but it's just the first time, then it become a simple thing. 

[Eric Bloodaxe]

12 minutes ago, Scorpion993 said:

I like to do car things on my own, at least, simple thing such as changing battery, but yeah...Fiesta MK8 battery isn't very user friendly

Yes, me too, and changing a battery used to be a very simple job!. The last time I needed to changed a battery was 2001, before that 1982, and both of those were around 10 years old and on cars that didn't do much mileage. It's concerning that batteries now seem to be failing at 2.😞

[robuk2]

The BMS is the cause of your problem, that`s the small sensor attached to the negative clamp of the starter battery, unplug it, this will get rid of stop/start and put the alternator into a standard continuous charging regime of around 14.2/4 volts, this will ensure the battery is kept fully charged even on short runs.

With the sensor connected the alternator is put into a smart mode of between the low 13 volts (no charge) and a high energy recuperation 15 volts, the longer the voltage stays at around 13 volts the less charge goes into the battery. The system is flawed, it saves marginal fuel and harms the battery by leaving it undercharged for long periods, especially when the car is used for mainly short journey`s.

The vid below shows a simple way to get rid of both stop/start and smart charging, the Merc is 2012 CGI and Had the disconnect over 13 months ago, it`s my daily driver mainly short journey`s, the battery on the Merc is dated 3811, that`s over 8 years old.

With the sensor gone you don`t need to code the battery and can use any battery you wish as long as it is sealed, AGM and EFB`s are only needed for stop/start.

 

[cjay1]

the bms should continuously charge the battery until it reached 80% charge it will then only charge when the car is in gear and moving without touching the accelerator. this is supposed to reduce fuel consumption and emissions. this shouldn't cause the battery to run flat as it will continuously charge when the battery is below 80%.

[Scorpion993]

Yes, I checked voltages and when is below 80% alternator charge with a voltage of 14.7. When is charged but you're using air conditioning or headlights, it runs at 13.6v. And, when the battery is near 100% and car engine is idle without any light or air, it just don't charge the battery that remains at 12.5v (with engine on).

When I had the poor battery, BMS keep to charge the battery with 14.7v, and...engine rpm in idle was a little bit higher, and start and stop just doesn't work. So, yeah, maybe it's better for battery but definitely fuel consumption and emissions is a little bit worse. And, the alternator could wear out early. I guess it's better to change a battery yourself rather than the alternator. 

[robuk2]

Quote

the bms should continuously charge the battery until it reached 80% charge it will then only charge when the car is in gear and moving without touching the accelerator. 

Exactly, the problem appears to be that an 80% charge is either not a high enough SOC for the EMU to engage stop/start or the SOC is not actually reaching that 80%. The point I am making is smart charging saves minimal fuel but can cause the battery to remain under 80% ( near to flat) for extended periods. This system is neither wanted or needed as has been shown with the disconnect on my Merc.

 

[robuk2]

Quote

So, yeah, maybe it's better for battery but definitely fuel consumption and emissions is a little bit worse. And, the alternator could wear out early. I guess it's better to change a battery yourself rather than the alternator. 

If you have dirty diesel then emissions should be a concern, petrol NO, co2 is a plant food not a pollutant. How long did past standard continuous charging alternators last?

The Merc in vid I refer to has the same 8 year old battery and alternator it had when the car was manufactured, you don`t need a computer to inform you when the battery needs replacing.

[Eric Bloodaxe]

1 hour ago, cjay1 said:

the bms should continuously charge the battery until it reached 80% charge it will then only charge when the car is in gear and moving without touching the accelerator. 

Just to get this clear in my head, the system will not charge the battery beyond 80% unless, in effect, you are coasting in gear? So if your daily driving routine is such that you are almost always on the gas while moving, your battery will never, or only rarely, get past 80% however many miles you do?

[cjay1]

correct but the system is smart enough to go beyond 80% every so often to refresh the battery to prevent sulfation 

[tef89]

2 hours ago, cjay1 said:

correct but the system is smart enough to go beyond 80% every so often to refresh the battery to prevent sulfation 

Thanks for the clarication.  Pretty surprisig really for me to learn that's how it works.

Although I wasn't impressed with the smartness of the system when, even though there wasn't enough power to even lock my car,  it was still happy enough to continously run the DRLS for a further 15 minutes 🤣 until the AA arived.

This thread has certainly opened my eyes to the technology involved in all this.

Am I being overly cautious replaceinng the battery after it went flat once ?  Keeping in mind my usage pattern.

[cjay1]

if the lights were still working then the battery is probably fine but i'd fully charge it with a battery charger to return the battery voltage back to healthy levels. if you really want to make sure no damage has been done many garages will test your battery for free and can be completed while you wait.

[tef89]

51 minutes ago, cjay1 said:

if the lights were still working then the battery is probably fine but i'd fully charge it with a battery charger to return the battery voltage back to healthy levels. if you really want to make sure no damage has been done many garages will test your battery for free and can be completed while you wait.

Thanks.  I don't have a charger or the environment to use one with the battery on the car so that's not really an easy option. 

The AA guy did a quick test after he got the car started and said just take it for a 30 minute run.  I have noticed the Stop Start didn't activate despite 3 good 45 minute runs in the last 10 days. 

The DRLs died just as the AA turned up. 

Think I'll call into the garage and get it checked properly. 

[williamweb]

15 minutes ago, tef89 said:

Thanks.  I don't have a charger or the environment to use one with the battery on the car so that's not really an easy option. 

The AA guy did a quick test after he got the car started and said just take it for a 30 minute run.  I have noticed the Stop Start didn't activate despite 3 good 45 minute runs in the last 10 days. 

The DRLs died just as the AA turned up. 

Think I'll call into the garage and get it checked properly. 

An alternator can't provide a comprehensive charge.At some point, the earlier the better, your battery needs to be on a charger👍

[Scorpion993]

I can confirm that, my S&S didn’t work until i charged manually my battery! It worked for some days because the battery was in poor condition, but it worked for a little. I guess if your battery is good, a good charging would be fine. 

[Eric Bloodaxe]

On 2/28/2020 at 12:04 PM, Eric Bloodaxe said:

Had the car in last week for service (car now done 10,000), all good on the inspection sheet except amber warning on battery charge - showing 11.96v as against 12.35v at last year's check.

Not the most scientific experiment I know, but found various reasons to drive about 90 miles yesterday, with only one switch off and restart en route and start/stop switched off by the button. Tested the battery voltage this morning - 12.5v.

Btw - FWIW as you might expect my battery appears to be identical to Gary's

[cjay1]

The charging system is able to output upto 110amps depending on demand this is more than enough to both run the car and charge the battery on most occasions if you have a high electrical load i.e. heated screens, heating and lights on etc then not much charging of the battery will occur. Not only does the system need to replace current used to start the car it also needs to be able to replace the power lost during S/S events.

[tef89]

So, an update.  Measured the battery and it turns out mine is 175mm(H) 278(L) and 175(W).  Next time your under the bonnet could you give yours a check Roger pls m8 ?

I've got a bunch of warranty items I want looking at so I've booked my car in at a nearby dealership.  They're gonna look at the battery etc as part of the warranty items.

So either they'll swap the battery under warranty or I'll buy a new one once it's been in.  I've nothing to lose by waiting a week or so.

I do appreciate the advice of getting it charged asap but it's not practical / cost effective at the minute.

Did some testing with a multimeter:

Engine off = 12.4V

Startup = Drops to 11V

Running = 14.7

[Eric Bloodaxe]

53 minutes ago, tef89 said:

Measured the battery and it turns out mine is 175mm(H) 278(L) and 175(W).  Next time your under the bonnet could you give yours a check Roger pls m8 ?

Just for you, I've battled through glorious sunshine to get to the car. Yes, same dimensions as we might expect (but you can't take anything for granted with a Ford.😀)

[tef89]

4 minutes ago, Eric Bloodaxe said:

Just for you, I've battled through glorious sunshine to get to the car. Yes, same dimensions as we might expect (but you can't take anything for granted with a Ford.😀)

You're a King amongst men Roger, thanks m8.  Makes it a lot easier choosing a replacement nearer to our Ah number.

Yeah I agree about Ford, always keeping us guessing.  Wierd ours are different to Elio's in Italy... Must be to do with Brexit 😮

[williamweb]

1 minute ago, tef89 said:

You're a King amongst men Roger, thanks m8.  Makes it a lot easier choosing a replacement nearer to our Ah number.

Yeah I agree about Ford, always keeping us guessing.  Wierd ours are different to Elio's in Italy... Must be to do with Brexit 😮

Code 100 it is then😁I'm so interested in this because my next car is probably going to be a Fiesta unless any of you good folks persuade me it's not a good idea👍

[tef89]

6 minutes ago, williamweb said:

Code 100 it is then😁I'm so interested in this because my next car is probably going to be a Fiesta unless any of you good folks persuade me it's not a good idea👍

Cheers Richard - looking like this one:

https://www.tayna.co.uk/car-batteries/exide/el652/

As for the new Fiesta, well I've had quite a few annoying little (electrical / tech) issues with mine but lots of people are super happy with theirs.

I've been looking for an alternative for later on in the year but I'm struggling to find anything suitable so, if the warranty issues are sorted (and none other occur), I may keep mine a bit longer.

[Eric Bloodaxe]

3 minutes ago, williamweb said:

I'm so interested in this because my next car is probably going to be a Fiesta unless any of you good folks persuade me it's not a good idea

Ha ha that's a whole new can of worms and probably needs a seperate thread! Have to say though, other than low battery charge mentioned earlier (which has not caused any problems, car always starts first press, so far) only issue I've had is with GPS signal disappearing and even that seems to have mysteriously corrected itself.

[williamweb]

3 minutes ago, tef89 said:

Cheers Richard - looking like this one:

https://www.tayna.co.uk/car-batteries/exide/el652/

As for the new Fiesta, well I've had quite a few annoying little (electrical / tech) issues with mine but lots of people are super happy with theirs.

I've been looking for an alternative for later on in the year but I'm struggling to find anything suitable so, if the warranty issues are sorted (and none other occur), I may keep mine a bit longer.

i couldn't see the code 100 on the battery but then i seen it in the heading Exide 100👍

[williamweb]

17 minutes ago, Eric Bloodaxe said:

Ha ha that's a whole new can of worms and probably needs a seperate thread! Have to say though, other than low battery charge mentioned earlier (which has not caused any problems, car always starts first press, so far) only issue I've had is with GPS signal disappearing and even that seems to have mysteriously corrected itself.

i'm thinking of going full fat st3 👍I think i'm right in saying the MK8 has a slightly smaller footprint than my Focus MK1 which suits me because i'll have slightly more space when travelling down my driveway👍