Battery change, step by step guide needed.

[Drive a Focus.]

I have a  March 2019 2.0 L ecoblue vignale  estate.

The battery has failed, so I need to replace it. I guess that it’s more involved than just undo terminals, swap battery and re-connect. Can anyone tell me exactly how to do it please?

The battery went flat during lockdown and never seemed to fully recover. Fully charged it yesterday, with CTEK MX 5,( apologies to Stephen Ford 😁) I checked the voltage this morning after leaving an hour for modules to shut down. Showed 12.48 volt. Tried to start it, got one revolution of the starter and then it stopped. Re -checked voltage, 11.51 volt. I think that it has failed!  I try not to do short runs in the car but it only gets used once or twice a week. I have had to charge it more recently,  keyless entry has only been working on driver’s door for a few months (4 door version) plus it keeps flagging up various things like “Hill start assist “, “Auto hold malfunction” etc after starting but these all work after a few miles. 

I have tried a search on You Tube but 2019 only brings up MK3.  Any help and advice would be appreciated.

[unofix]

9 minutes ago, Drive a Focus. said:

11.51 volt. I think that it has failed!

Agreed 👍

Disconnect the two battery terminals. Undo the clamp and then remove anything else that gets in the way like the airbox. Sorry don't have exact info for your model. Remember to give the new battery a charge before fitting.

After fitting the battery you will need to reset the BMS. Using one of the two systems posted below.

[unofix]

On 3/29/2023 at 8:13 PM, unofix said:

How to reset the BMS method 1

 

 

[unofix]

On 3/29/2023 at 8:14 PM, unofix said:

How to reset the BMS method 2

 

This is the method for a Focus Mk4

[Drive a Focus.]

Thanks Unofix, I knew that you would reply.

Will the window memory require a re-set? or the Panoramic roof?

What order should I disconnect/ reconnect the terminals please?

Need to decide which make of battery to buy next. Any recommendations?

[unofix]

Hi Michael,

In an ideal world, disconnect the negative terminal first. When refitting reconnect the negative terminal last.

Sometimes it's just not possible to reach the negative terminal after the battery is fully in place and there is no option other than to do it the other way round.

The windows will need the 'Bounce Back' reset. Full procedure can be found in the owners hand book. It is an absolute pain to get it to work, and i expect you will have at least 5 or 6 tries on the first window. It gets a little easier as you do each one and you get the method correct. There is no radio code needed. The roof should not need reset.

BEFORE connecting the new battery make sure to leave the drivers door standing open. Central locking can be a funny thing and many a person has been locked out when in the process of connecting the new battery.

[Drive a Focus.]

I bought a new Varta battery from Tanya, very good service and quick delivery. I fully charged it before fitting as was suggested.

Replacement was fairly straightforward, I had to remove the air box to allow the battery to slide forward out of the battery box. The positive cables were a bit of a struggle to clear the terminal post as they are held by tie wrap clips just below the battery box. A bit of careful wiggling allowed just enough slack to get the cables clear of the battery. Then it was just put the new battery in and re-connect everything, and re-set the BMS.

The car seems to drive better and smoother now. The stop/start even works now, ( it hasn’t worked for over a year.) When the engine stopped at the first junction that I came to I thought that I had done something wrong and had damaged the electrics before I realised what had happened.

 The air box has one broken locating pin and one of the other rubber grommets that another pin fits into is missing. The pin for the missing grommet has signs of distress from rubbing against the metal support and has obviously doing this for a while. The car has only been serviced by Ford dealership so I think that I can guess how this damage has occurred.

When I looked at the old battery I found that it still had one of the transport vent plugs still in place, the end nearest the bulkhead so not easily visible. Could this have contributed to the failure of the battery?

A big thanks to  Unofix for all the advice. 👍

 

 

[mjt]

I don't think it needs both vent plugs to be removed. In some applications it may have a drain tube fitted and I think it's designed so that the one that's most convenient for venting can be removed.

[unofix]

2 hours ago, Drive a Focus. said:

I bought a new Varta battery from Tanya, very good service and quick delivery.

As it happens my own battery is on it's last legs, has been for a few months. I'll have to replace it very soon and will most likely get the replacement from Tanya.

[unofix]

Just ordered my new Yuasa YBX7096 battery for £117.90 from Tanya. Despite all good efforts in the last few days I've not been able to get the SOC above 62% which is causing issues with the door locks.

 

[Karbonfaiba]

21 hours ago, Drive a Focus. said:

The car seems to drive better and smoother now.

I'm fascinated to hear that, it's not just placebo is it?

I had a similar feeling back on my old battery; once I gave it a full charge it just drove better, then 2 days later it was back to dragging itself around. I was fortunate enough to only have low voltage symptoms, not DTCs.

Now that I've had my uprated AGM Bosch S5A08 fitted, that "fully charged" feeling is a consistent experience. Auto gearshifts are smoother, power steering strength more predictable, faster folding mirrors and windows, and of course Start/Stop is working all the time, even 5 minutes on a cold engine - it will work with a SOC around 60%.

Not to state the obvious, but Ford's choice of battery is based on their minimum, not the cars optimum.

[unofix]

New battery installed and BMS reset (method 2 above).

[Tizer]

34 minutes ago, unofix said:

New battery installed and BMS reset (method 2 above).

And time for Stop/Start to get on your nerves unless you have disabled it 😁.

Was the new battery the same size or if not did it fit ok? 

[unofix]

5 minutes ago, Tizer said:

Was the new Battery the same size or if not did it fit ok? 

The new battery was an identical size to the original, so no problems fitting it 👍

I have a little gizmo fitted that automatically turns S/S off 5 seconds after the ignition is turned on, so I don't have to worry about that 🤣

You'll note that despite the SOC being 85% the battery is still being charged at a rate of 2 Amps. It will be interesting to see if continues up to the 95% that I have set.

[Tizer]

6 minutes ago, unofix said:

You'll note that despite the SOC being 85% the battery is still being charged at a rate of 2 Amps. It will be interesting to see if continues up to the 95% that I have set.

I did wonder about that when I saw your Screenshot. 

As far as I know, if you had left it at 80% it would only charge on the overrun and discharge when your foot was on the gas until you got back to 80%.

[Drive a Focus.]

7 hours ago, unofix said:

New battery installed and BMS reset (method 2 above).

Did you have to re-set the clock and widow bounce back ( as stated in the handbook)? Both of mine didn’t need it, which surprised me. 

 

[unofix]

The windows didn't need resetting this time. Previously when I've disconnected the battery for other reasons I've needed to reset them.

I've never needed to reset the clock, but as per normal I did have to reset the tyre pressures which had defaulted to 'bar' instead of 'psi' and also had to reset the Alarm system option which had defaulted to asking me if I wanted full or part guard each time I switched off.

Everything else seems to have remained unchanged.

 

[Drive a Focus.]

Yes I had to do the same for tyre pressure and alarm. BMS re-set was the second version also.

[unofix]

On 5/13/2023 at 2:27 PM, Tizer said:

As far as I know, if you had left it at 80% it would only charge on the overrun and discharge when your foot was on the gas until you got back to 80%.

Well below are some photos that have probably never been seen before !!!

I confirm that the SOC of my car is set to 95% (might reduce that to 90%). note the 'Charge Mode'

[Tizer]

5 minutes ago, unofix said:

Well below are some photos that have probably never been seen before !!!

I confirm that the SOC of my car is set to 95% (might reduce that to 90%). note the 'Charge Mode'

I've never seen a battery at 100%, and either that or the Slow Regen Allowed mode almost looks like knocks off the Smart Charging judging by the Voltage.

I have only seen my one above its Target of 80% once and it heavily discharged with my foot on the Gas and heavily charged on the overrun. I can't remember what Charging Mode mine was in at the time.

I'm surprised that the car has charged the battery above 95%, it will be interesting to see what happens to these figures in a few weeks time when things settle down.

[unofix]

1 hour ago, Tizer said:

I'm surprised that the car has charged the Battery above 95%, it will be interesting to see what happens to these figures in a few weeks time when things settle down.

Yes I was surprised that it was still charging, but I was on a road where there were lots of downhill stretches. So according to my vehicle tracker the current battery voltage is 12.69V after being parked for 1 and a half hours.

[archie2000]

On 5/11/2023 at 12:40 PM, Karbonfaiba said:

I'm fascinated to hear that, it's not just placebo is it?

I had a similar feeling back on my old battery; once I gave it a full charge it just drove better, then 2 days later it was back to dragging itself around. I was fortunate enough to only have low voltage symptoms, not DTCs.

Now that I've had my uprated AGM Bosch S5A08 fitted, that "fully charged" feeling is a consistent experience. Auto gearshifts are smoother, power steering strength more predictable, faster folding mirrors and windows, and of course Start/Stop is working all the time, even 5 minutes on a cold engine - it will work with a SOC around 60%.

Not to state the obvious, but Ford's choice of battery is based on their minimum, not the cars optimum.

Interestingly, last year I was having issues with occasional power loss and sluggishness from cold on my 2018 Vignale. I had it in and out of Fords a number of times. Besides changing the injectors (twice), software update, 4 oil changes they also replaced the battery and I swear it has never run better since the battery was replaced.

I upped the SOC to 90% via FORScan and I've not had any problems with stop/start, door locks, etc since and it's been well over 12 months now.

[unofix]

This mornings battery update (my SOC is still set at 95%).

[Nimrodmk8]

Blimey, seems quite a hassle to change the battery now, my last car took the old one out connected the terminals on the new battery, no charging required and drove off, when mine needs doing might take it to a dealer, I guess that's what they want though.

[Drive a Focus.]

9 minutes ago, Nimrodmk8 said:

Blimey, seems quite a hassle to change the battery now, my last car took the old one out connected the terminals on the new battery, no charging required and drove off, when mine needs doing might take it to a dealer, I guess that's what they want though.

It’s the first time that I have changed a battery in the last 40 years. I wouldn’t say that it was a hassle. It was fairly easy really. The prices for supply and fit was about £100 more than the online price.