Focus MK4 battery replacement

[ADR91]

Hello there,

 

So my 2018 Ford Focus MK4 recently underwent its scheduled biennal service and according to the dealer, its battery needs to be replaced.

 

When I mentioned I was considering to carry out the replacement myself, he said that if I were to do so, he strongly advised against replacing the battery with anything but the exact same model that originally equipped the car from the factory.

 

According to him, the BMS on modern Ford vehicles is extremely picky when it comes to the battery type, and cannot correctly determine the state of charge of anything that doesn't precisely match the exact specifications of the OEM battery in terms of capacity, cold cranking amps as well as reserve capacity.

 

He went on to say that based on his experience, installing an aftermarket battery was guaranteed to result in some serious electronic disturbances, and that if I were to encounter any of those after replacing the battery with something else than the OEM model, he would just assume that it's because of the aftermarket battery and wouldn't even bother investigating the issue.

 

So the question is : is the dealer right about this or is he just talking rubbish as I suspect?

 

Has anyone here got any experience with replacing an OEM battery with an aftermarket model on a Focus MK4 (or any other modern Ford vehicle for that matter)? Did you run into any issues ?

 

Any advice would be appreciated.

[Wino]

Why does the battery need replacing ? 

[unofix]

2 hours ago, ADR91 said:

or is he just talking rubbish as I suspect?

YES !!

[unofix]

So as already asked by @Wino why does the battery need replaced on a 2018 Focus ?

please, please don't say the words "because Stop/Start doesn't work" 😧

[ADR91]

1 hour ago, Wino said:

Why does the battery need replacing ? 

 

45 minutes ago, unofix said:

So as already asked by @Wino why does the battery need replaced on a 2018 Focus ?

please, please don't say the words "because Stop/Start doesn't work" 😧

Thanks to both of you for your quick replies.

The dealer said the car has registered dozens of DTCs in the past few months related to modules having insufficient voltage. He tested the battery with some testing device which reported the battery was at 25% SoC.

I have also seen such DTCs myself about a year ago when I plugged in my OBD interface and read the DTCs with Forscan, and have also had a few electronic glitches that could very well be explained by a weak battery, for lack of a better explanation. For instance I sometimes get an error message stating "Hill assist unavailable" when I switch on the ignition without actually starting the engine, suggesting some module is getting upset when it's powered solely from the battery, as opposed to being powered by the alternator.

That being said, whenever I take my car for a couple of hours long drive or so, and then let it rest for about half a day in order to allow for the SoC to be recalculated, I always find the Stop and Start system to be operational, suggesting that the BCM is happy with the battery's condition. Considering how many Focus MK4 owners have problems with the Stop and Start system, I find this to be quite reassuring. Also it's worth noting the battery has already been replaced once before the car was sold to me, in January 2020, so the battery that's currently fitted isn't even that old. On top of that, given that I use my car mostly for medium to long distance trips, I use it rather seldom and it's not uncommon for it to stay parked for about 10 days or so without me starting it, so that could account for the voltage drops.

However the dealer says that even if I were using my car only once every two weeks there shouldn't be so many DTCs related to low voltage, and therefore recommends replacing the battery before matters get worse.

To be clear, I haven't decided yet whether or not I should be replacing the battery ASAP. I will look into this matter carefully by monitoring the voltage and using Forscan to see what the BCM has to say about the battery's SoC under different circumstances before I decide what course of action I should take.

However, if I decided to replace the battery (which eventually will become necessary at some point), I would like to know what my options are.

[Tizer]

The original factory fitted battery would most likely be a Varta EFB type and 600/60 Amps if it is a Manual Petrol model, probably 650/65 for an Auto. I'm not sure about the Diesel Engines.

If you want to play safe then there should be details on either the Varta website, or a lot of people in the UK buy there Batteries online from Tanya Batteries or on the battery itself if Ford fitted it.

Personally if I was changing my battery I would get the biggest capacity one that was the same size externally and reset the BMS with FORScan or use the sequence of button presses. I personally wouldn't go down the AGM route because the Smart Charging System has been set up for EFB and I don't think there is an option to change it in FORScan. This is maybe what the garage was hinting at.

You can also change the size of Battery programmed into the car with FORScan and an Extended Licence. I'm not sure how important that is given that a lot of our cars have been programmed at the factory with the wrong sized ones anyway.

[unofix]

2 hours ago, ADR91 said:

He tested the battery with some testing device which reported the battery was at 25% SoC.

Well i guess the car doesn't start and nothing works !!! or do I detect some Bull ?

Please see the State Of Charge (SOC) chart shown below.

To avoid what could potentially be a very long post I will keep to the basics as much as possible.

The Smart charging system on your car if still set at the factory default will be 80%. Therefore you could drive to the Moon and back and the battery will never be more than 80% charged. Using FORScan this can easily be adjusted to 95%

There is a list of types and sizes of battery available which can be viewed using FORScan. You (like most others) will probably find that the battery fitted to the car and what the car thinks it has is two different things. There is much speculation as to why this is, but as yet know one has been able to offer a definate reason. So I'd probably advise not to change this unless it is the wrong type of battery.

.......and of course your Stop/Start system doesn't work. I'm always amazed when some one says it does. The list of conditions that have to be met before the system will stop the engine is vast. At the end of the day the system is designed to work when the car thinks it should and not when the driver thinks it should.

To summarize: First change the SOC using FORScan and set it to 95%. Next check the battery type is set correctly, but don't adjust if it is only the capacity that is wrong. Don't ever reset the BMS unless you fit a new battery. Otherwise the 'Days in Service' will be set back to zero.

Lastly charge your battery with a Smart charger. Ensure that the positive lead is connected to the battery positive terminal. Connect the negative lead to the chassis main earth point - NOT the battery terminal. Leave it on charge for a full 12 hours even if the charger is saying it is complete.

The other thing that you should consider is, 'do you trust the dealer' ???

[aot871]

Where is the chassis main earth point  or is it any part of the body?

[ADR91]

4 hours ago, Tizer said:

Personally if I was changing my Battery I would get the biggest capacity one that was the same size externally and reset the BMS with FORScan or use the sequence of button presses. I personally wouldn't go down the AGM route because the Smart Charging System has been set up for EFB

That's exactly what I was planning to do in case I'd have to change the battery. My Focus is a manual 1.0 L ecoboost petrol model fitted with the Varta 60/600 OEM battery, which measures 278 x 175 x 175. However I think I heard some later models are fitted with a 278 x 175 x 190 mm battery, so if the battery holder happens to be compatible I might be able to go for that size.

2 hours ago, unofix said:

Well i guess the car doesn't start and nothing works !!! or do I detect some Bull ?

Please see the State Of Charge (SOC) chart shown below.

Yeah, I also found 25 % to be a bit low to be true, so I asked the dealer how he had determined that SoC and he replied : "I used a battery tester that's worth over a thousand euros and that we're required to use by Ford." as if the device being expensive and endorsed by Ford was some kind of proof of accuracy...

2 hours ago, unofix said:

.......and of course your Stop/Start system doesn't work. I'm always amazed when some one says it does

I'm not sure if you just didn't read my reply carefully enough, or if you are trying to dispel what I wrote about my Stop and Start system being operational, but I can assure you that it DOES actually work, and that it does so pretty flawlessly, provided I use my car on a daily basis. Be amazed if you will. The only circumstance where it doesn't work is when I don't drive my car for more than two or three days in a row, which admittedly, occurs more often than not.

2 hours ago, unofix said:

To summarize: First change the SOC using FORScan and set it to 95%. Next check the battery type is set correctly, but don't adjust if it is only the capacity that is wrong. Don't ever reset the BMS unless you fit a new battery. Otherwise the 'Days in Service' will be set back to zero.

Lastly charge your battery with a Smart charger. Ensure that the positive lead is connected to the battery positive terminal. Connect the negative lead to the chassis main earth point - NOT the battery terminal. Leave it on charge for a full 12 hours even if the charger is saying it is complete.

Thanks for the advice. However, I don't think I'm going to change any parameters using Forscan because as I said, my Stop and Start system is currently working and I'd rather keep it that way. Setting the desired SoC to 95% would likely cause the system to operate much less often, if at all. Moreover, I paid for extended warranty and from my experience with Ford so far, I feel they'd be willing to jump onto any pretext to claim the warranty is void should I ever need it, so I'd rather not mess with settings unless I really need to.

As for charging the battery with a smart charger, that's only ever a temporary solution : given that the battery has consistently shown signs of weakness for at least 12 months now, despite the car being regularly driven over pretty long distances, it has clearly suffered a loss of capacity that no kind of charging is ever going to repair.

I guess that this loss of capacity is normal and that it would easily go unnoticed if only I drove the car more frequently. Actually, given how seldom I use the car, perhaps it would be advisable to use a charger in trickle charge mode whenever I'm not using the car for a prolonged period, but unfortunately I don't have any electrical outlet available near to where my car is usually parked.

So as things stand, I believe the only remedy to the issues I'm experiencing would be indeed to replace the battery, which raises the following questions :

1. How serious exactly is the issue with the voltage drops ? Can I still go on with that situation for several months ? Or perhaps even over a year ?

2. If I decide to replace the battery, what's my best option when it comes to selecting the right model ? Of course it should be EFB, but should I rather go for OEM or aftermarket ? And if I go for aftermarket, would it be advisable to choose for a battery with significantly better specifications than the factory-fitted model ?

2 hours ago, unofix said:

The other thing that you should consider is, 'do you trust the dealer' ???

Obviously, no, I don't trust him entirely, or else I wouldn't be asking for advice here.

Yet believe it or not, from the many car repair professionals I've had to deal with so far, this guy is probably one of the best I've seen...

Anyway, I've since long come to the conclusion that the only way to really take good care of your car is to take matters in your own hands, provided you've got the required skills and tools, that is. Unfortunately, not everyone has got that luxury.

[Wino]

10 hours ago, Tizer said:

The original factory fitted Battery would most likely be a Varta EFB type and 600/60 Amps if it is a Manual Petrol model, probably 650/65 for an Auto. I'm not sure about the Diesel Engines.

If you want to play safe then there should be details on either the Varta website, or a lot of people in the UK buy there Batteries online from Tanya Batteries or on the Battery itself if Ford fitted it.

Personally if I was changing my Battery I would get the biggest capacity one that was the same size externally and reset the BMS with FORScan or use the sequence of button presses. I personally wouldn't go down the AGM route because the Smart Charging System has been set up for EFB and I don't think there is an option to change it in FORScan. This is maybe what the garage was hinting at.

You can also change the size of Battery programmed into the car with FORScan and an Extended Licence. I'm not sure how important that is given that a lot of our cars have been programmed at the factory with the wrong sized ones anyway.

It's a 760/70 battery on the 1.5 diesel. 

[Tizer]

4 hours ago, Wino said:

It's a 760/70 battery on the 1.5 diesel. 

Thanks, It's good to know that size will fit comfortably in the tray.

Our Air Filter Ducting runs over the top of the battery so height may be the limiting factor when I eventually do have to change mine for something with a more sensible capacity.

[ADR91]

Juste to provide a little update: ever since my car was serviced, which was about a month ago, its stop & start system has been working consistently, even on one occasion where I started it after it had remained parked for about two weeks, which makes me think the dealer might have charged the battery when my car was out for service at his workshop.

So it might be a good thing to charge the battery with a charger every so now and then.

Still, in case I'd have to replace the battery, which will become necessary eventually, does anyone have actual experience with using an aftermarket battery as a replacement in a modern Ford vehicle? And does anyone have a recommendation regarding a specific brand?

Also, happy new year everyone!

[ADR91]

Hmm, I don't really see what there's to be sad about, @unofix...

Care to elaborate?

[alexp999]

14 hours ago, ADR91 said:

Juste to provide a little update: ever since my car was serviced, which was about a month ago, its stop & start system has been working consistently, even on one occasion where I started it after it had remained parked for about two weeks, which makes me think the dealer might have charged the battery when my car was out for service at his workshop.

So it might be a good thing to charge the battery with a charger every so now and then.

Still, in case I'd have to replace the battery, which will become necessary eventually, does anyone have actual experience with using an aftermarket battery as a replacement in a modern Ford vehicle? And does anyone have a recommendation regarding a specific brand?

Also, happy new year everyone!

I put a Halfords EFB battery in my mum's Kuga with no issues.

Just have to remember to reset the BMS so it knows the battery has been changed, but that's for any new battery regardless of brand.

[WarhawkCZ]

I update this topic as the title is most descriptive and many google hits may bring people here.

Today, I replaced the battery in my Focus. The config is 1.5L petrol, 134kW, estate, MY2020. The original battery was slowly dying. It all started during pandemic when my battery once depleted to ~3V. Forum members suggested that this occasionally happens when the car is stationary and some of the systems do not turn off properly. I recharged the battery and kept using the car. The start-stop system practically never kicked in. This was a good thing. The situation with a completely depleted battery repeated two years after the first incident. My car went through maintenance at the dealer this summer. The dealer confirmed that the car reports low battery voltage but suggested keeping it. The original ford battery was ridiculously expensive. Something like 2.5x of the normal street price. Now, as winter came, I could feel that the engine startup was somehow slower. Additionally, I got a notification to my cellphone that remote services were disabled. It was time to replace finally the battery.

The replacement is not as straightforward as I experienced with my previous cars.

1. It is important to release the air filter from the position. You must do this and there is no way around it. I removed the internal filter and then the top lid (1). Protect the engine intake!
2. You need to remove two plastic bolts (2) that hold the intake in position and the hose that goes to the engine (3)
3. What you want to achieve is that you have access to the bottom part of the air filter housing (4). There are ~3 rubber silent blocks that hold the plastic case in place. You remove it by pulling it up with reasonable force. It is type of a press-fit connection.
4. Steps 1 through 3 gain you bit more room for the battery removal.
5. Remove screws around the battery. Start with the BMS cable (5). Positive + negative terminals (6) and the bracket screws (7, 8).
6. I suggest you cover battery terminals with e.g. a duck tape during the operation. Shortening the battery is no fun.
7. Arrange cables such they allow for battery removal. Duck tape was helpful once again.
8. Now you can lift the battery and then slide it towards the filter. Without the filter removal the battery becomes loose but can't go out. About 2-3cm forward do the job and you can finally lift the battery from the base.
9. Install the new battery using the same procedure backwards. Connect the negative terminal last. Don't forget to remove yellow protective caps (they are shown on the picture).
10. Reset the BMS (detailed description somewhere in this topic)
    • Ignition ON
    • High-beam 5x
    • Brake pedal 3x
    • wait 15s
    • battery icon on the cluster blinks 3 times
    • done

Note: VARTA has battery finder (https://www.varta-automotive.de/de-de/battery-finder). I put there numbers from the original Ford battery (jx6t-10655-fa) to get the suitable replacement (Blue Dynamic EFB 570 500 076).

 

PS: Feel free to suggest what I could have done better. I am not a profi, just a guy who fixes his stuff.

PPS: English is not my first language. The terminology may be incorrect.

PPPS: My cellphone died in the middle of the operation. For this reason, pictures are not the best.

[alexp999]

You don’t need to remove the whole front air guide. You can disconnect the air box lid from the guide at that flexible part. 

[WarhawkCZ]

3 minutes ago, alexp999 said:

You don’t need to remove the whole front air guide. You can disconnect the air box lid from the guide at that flexible part. 

I was not able to remove it. It was cold and i could not make it free. What kind of trick is needed there? I could feel a knob from the bottom but could not figure it out.

[alexp999]

I just used a flat blade screwdriver to release the tabs. I could see it had been done before.