Back with updates; I hooked up the charger, and Forscan and I could see the SOC increasing as I wanted to make sure the BMS does in fact detect that the battery is being charged.

Powered of Forscan and left the battery to charge. About three hours later the charger showed the charging has finished and the battery as being Ok. So it switched to trickle charging. I measured the current and it was about 80 mA flowing in the battery. I measured voltage and the charger was "trickling" at about 12.7 V. I did not wakeup the car again to check the SOC at this point.

So my next thought was that something is for sure wrong. I have used the same charger on other discharged batteries and it took at least 10 hours to recharge those batteries.

I left it over night, and this morning the voltage was around 12.5 V. Hooked up forscan, and SOC only 30%. So this idea did not work as I expected.

I have four options left as far as I can tell:

1. Go to a garage to get a battery test and buy a new battery (if test results are bad), reset BMS (sets me back about 200+ euros I guess)

2. Disconnect battery and upon reconnection maybe things get better. 

3. Reset BMS and see what happens. If SOC drops fast -> buy new battery.

4. I have an 8-9 hour trip coming in two weeks. Wait until then and see if somehow the SOC increases during this trip. If not, buy a new battery.

One correction I should make regarding the deep sleep current draw. It is about 35 mA, not 50 mA. Turns out I had to read the clamp meter manual to properly zero it 😄

 

Thank you all for your inputs.

8 minutes ago, RaduF86 said:

2. Disconnect battery and upon reconnection maybe things get better.

This option will cost you nothing but from what you say I think you need a new Battery.

 

8 minutes ago, RaduF86 said:

I should make regarding the deep sleep current draw. It is about 35 mA,

That is good for these cars, 50 mA is the maximum allowed.

Yes, in the back of my head I am quite convinced I need a new battery. I am just consciously trying to avoid the unavoidable.

The good point in all of this is that I have learnt quite a few new things.

40 minutes ago, RaduF86 said:

Yes, in the back of my head I am quite convinced I need a new battery. I am just consciously trying to avoid the unavoidable.

The good point in all of this is that I have learnt quite a few new things.

And the first sign of madness is repeating the same mistake over and over again 😁

So I got myself a trickle charger. Where is the best earthing point under the bonnet. 

8 minutes ago, Stevie H79 said:

So I got myself a trickle charger. Where is the best earthing point under the bonnet. 

There is a nice "stud" coming out of the body that the front suspension top mount fixes to, that is designed for this purpose. Just to the right of the battery that a big thick cable connects to, it's the main chassis ground point.

One final update from my battery analysis/issue.

I disconnector the battery and also removed it from the car. Turns out for the Focus mk4 mhev the only way to remove the battery is to remove the airbox as well. The battery slides inside its tray and it cannot be lifted (this is a really bad design in my opinion).

Anyways, I got it removed, recharged it, and left it in open circuit to let the voltage stabilize for some hours. Then I hooked up one of those cheap battery testers (the BM550 which got quite a few good reviews when compared to more expensive Bosch testers, but apparently the battery must be charged for it to be accurate) and it showed:

- Battery internal resistance 3.86 mOhm

- Battery State-of-Health 91% 

I am not taking these results as 100% accurate, especially the SOH which is only an estimation, but the internal resistance seems low enough for the battery to still be in good shape.

I reinstalled and reconnected the battery, locked the car and left it over night.

Next morning everything worked well, AC is back on, loud beeps, and no more battery saver message on the Synch 3 display. After a few short trips during the morning I connected forscan and the BMS/BCM recalibrated at 70% SOC. Seems a little low, but it is what it is for now. By the way, each test the brake-by-wire unit does after engine turn off draws around 6-7 amps, and that thing does quite a few tests before the car goes to sleep. Of course other ecus are awake also during this time, but the brake one seems to be a particularly high consumer.

 

Conclusions:

Indeed disconnecting and reconnecting the battery does force the BCM to do a recalibration of the SOC. SO thank you for this tip!

I will further keep an eye on it, and if the cheap battery tester shall be proven wrong, I shall order a Yuasa YBX 7096. I saw it is recommeded around the forum.

Since this is the first time the car no longer complains, I also disabled the Connected services to the FordPass app, and the keyless entry. When I shall find some more time to properly diagnose if these cause any unwanted high current drain which might cause the car to go in deep sleep mode again, I am leaving them off.

 

Thank you all for you help!

Hi Chaps

So it's been a month and I thought I'd give an update. I bought the charger and connected it up for about 4 hours and got the battery back to full. All was well, the lights operated when locking/unlocking and everything seemed normal except the Start/Stop still isn't working. Fast forward to about 5-6 days ago and I woke up to message from FordPass app declaring that certain features were switched off to preserve battery. Working away for a few days meant that it had to wait till the end of the week before I could attend to it. Friday I connected the charger back up and got it to full again. This morning (Monday) I had the Pass App message AGAIN! I'm now considering getting a USB to OBD 2 cable and finding a way to alter the SOC for the battery. I've been looking at changing the car but unfortunately I'm probably stuck with it for another 16-17 months. My faith in Ford has completely gone, I waited a long time for this car and it's the first brand new car I've owned but the experience of 9 month's waiting back and forth with the dealer I was overjoyed when it finally arrived . Little over a year into ownership and I just want rid of it. I paid over £200 for a replacement battery on previous Focus and lost a days wage I'm not prepared to do it again. 

15 minutes ago, Stevie H79 said:

Hi Chaps

So it's been a month and I thought I'd give an update. I bought the charger and connected it up for about 4 hours and got the battery back to full. All was well, the lights operated when locking/unlocking and everything seemed normal except the Start/Stop still isn't working. Fast forward to about 5-6 days ago and I woke up to message from FordPass app declaring that certain features were switched off to preserve battery. Working away for a few days meant that it had to wait till the end of the week before I could attend to it. Friday I connected the charger back up and got it to full again. This morning (Monday) I had the Pass App message AGAIN! I'm now considering getting a USB to OBD 2 cable and finding a way to alter the SOC for the battery. I've been looking at changing the car but unfortunately I'm probably stuck with it for another 16-17 months. My faith in Ford has completely gone, I waited a long time for this car and it's the first brand new car I've owned but the experience of 9 month's waiting back and forth with the dealer I was overjoyed when it finally arrived . Little over a year into ownership and I just want rid of it. I paid over £200 for a replacement battery on previous Focus and lost a days wage I'm not prepared to do it again. 

What battery did you have fitted?

A lot of us have switched to the YBX7096 which is only £100 but higher Ah than the rubbish Ford fit from Factory.

13 minutes ago, alexp999 said:

What battery did you have fitted?

A lot of us have switched to the YBX7096 which is only £100 but higher Ah than the rubbish Ford fit from Factory.

I've still got the original factory fit battery. I don't know what the replacement was on the previous car, it was whatever the RAC man had in his van, I just had to get it going again.

37 minutes ago, alexp999 said:

What battery did you have fitted?

A lot of us have switched to the YBX7096 which is only £100 but higher Ah than the rubbish Ford fit from Factory.

When you switched to the YBX7096 did you also increase the SOC for this new battery? Or good to go as is? I'm so sick of this issue that I am going to buy this battery everyone is praising.

5 minutes ago, Gus T said:

When you switched to the YBX7096 did you also increase the SOC for this new battery? Or good to go as is? I'm so sick of this issue that I am going to buy this battery everyone is praising.

I'm still on 80% target SoC. I changed the battery type more out of curiousity, but it doesn't make much difference and you need to find the correct value for your calibration (Forscan UI values are wrong).

It only really needs a BMS reset when you change the battery.

Only other thing I'll say is that while it definitely is a better battery, if there is something about Sync 4, or the Mk4.5 causing proper battery drain, it will just give you bigger breaks between problems. But I haven't been on a long journey in ages and my stop/start is still activating, so it seems to be better than the factory 60 Ah battery at least.

2 minutes ago, alexp999 said:

I'm still on 80% target SoC. I changed the battery value more out of curiousity, but it doesn't make much difference and you need to find the correct value for your calibration (Forscan UI values are wrong).

It only really needs a BMS reset when you change the battery.

Only other thing I'll say is that while it definitely is a better battery, if there is something about Sync 4, or the Mk4.5 causing proper battery drain, it will just give you bigger breaks between problems. But I haven't been on a long journey in ages and my stop/start is still activating, so it seems to be better than the factory 60 Ah battery at least.

Okay good to know, thanks!

Having read some posts on Forscan it doesn't appear the mk4.5 is covered. There is a free download available but I really need to find someone with Forscan that can change the SOC to higher than 80%. 

1 hour ago, Stevie H79 said:

but I really need to find someone with Forscan that can change the SOC to higher than 80%

I've never tried on a Focus Mk4.5 but have set it to 95% on my Mk4 without a problem.

If you're passing A1(M) J61 Bowburn Interchange any time I'll give it a try for you.

3 hours ago, Stevie H79 said:

Hi Chaps

So it's been a month and I thought I'd give an update. I bought the charger and connected it up for about 4 hours and got the battery back to full. All was well, the lights operated when locking/unlocking and everything seemed normal except the Start/Stop still isn't working. Fast forward to about 5-6 days ago and I woke up to message from FordPass app declaring that certain features were switched off to preserve battery. Working away for a few days meant that it had to wait till the end of the week before I could attend to it. Friday I connected the charger back up and got it to full again. This morning (Monday) I had the Pass App message AGAIN! I'm now considering getting a USB to OBD 2 cable and finding a way to alter the SOC for the battery. I've been looking at changing the car but unfortunately I'm probably stuck with it for another 16-17 months. My faith in Ford has completely gone, I waited a long time for this car and it's the first brand new car I've owned but the experience of 9 month's waiting back and forth with the dealer I was overjoyed when it finally arrived . Little over a year into ownership and I just want rid of it. I paid over £200 for a replacement battery on previous Focus and lost a days wage I'm not prepared to do it again. 

Hi Stevie,

Before changing the battery I believe the car needs a proper diagnostic to see first of all if there is any high current drain during sleep. If there is, the next step is to figure out what is causing it. A new battery (even bigger one) will still discharge and your problems will not go away. Also hooking up forscan keeps the car awake so even if you check the SOC or you change the target SOC you won't find what is draining your battery.

One more thing you could do, but I am not sure how safe it is, is to check the charging while driving. Probably best to have a co-pilot to read the data on the laptop (once you have forscan) and see how this Smart Charging behaves. Ideally it should not discharge the battery, at least not too much, but it should only charge it during engine braking. That is the theory at least. I did not actually test this because it is hard to find the time for it.

I haven't posted in a while because it my case everything seems to be back to normal, except the keyless entry which I did not enable again because I did not find the time to properly test if the sensors are/aren't keeping the car awake. But I did enable the modem again and haven't seen a DeepSleep message in weeks, so the connected features are not an issue. True that I have an MK4 so no "Updates Over The Air" in my case.

Cheers!

On 4/29/2024 at 4:11 PM, alexp999 said:

I'm still on 80% target SoC. I changed the battery type more out of curiousity, but it doesn't make much difference and you need to find the correct value for your calibration (Forscan UI values are wrong).

It only really needs a BMS reset when you change the battery.

Only other thing I'll say is that while it definitely is a better battery, if there is something about Sync 4, or the Mk4.5 causing proper battery drain, it will just give you bigger breaks between problems. But I haven't been on a long journey in ages and my stop/start is still activating, so it seems to be better than the factory 60 Ah battery at least.

Going to buy the Yuasa battery today from here. One question I have though is do you know the proper way to reset the BMS on a MK4.5 Focus? I see loads of info and videos for the MK4 but nothing on the 4.5.. I imagine it is the same however I thought I'd ask you incase you knew? Also should the BMS be reset straight after the battery change? Thanks!

Hi, recently bought a 2022 Focus ST Estate. It's still got a year left on the warranty. Picked it up from Hills ford in Malvern.

The first day we collected it we did close to 300 miles. Got home, I sat in it's to check some bits out, the puddle lights and DRLs wouldn't come on, neither would the boot lights. I assumed that there was a setting in the SyNc menu - nothing. 

I emailed Hills Ford (51 miles from my house) and they suggested I take it to a local dealer.

However, day after the puddle lights worked. Which was weird.

Today my wife has gone to put something in the boot. Again no puddle lights, no boot lights.

I've never experienced start/stop on this car to date.

I keep getting the ford app message about battery saving too.

Having read the majority of this thread, I'm assuming I need to change the battery to the larger one and reset the Battery management system?

I'm going to throw the multi meter onto the battery tomorrow and see what it's reading to confirm.

Previous owner only did 5k in 2 years, so based on all of the discussions on this thread the battery might be destroyed too...

Also the rear view camera has stopped working 🤬. The view looks like I'm on acid. I'm assuming this isn't related.

Really annoying as the car is fabulous other than this.

 

6 minutes ago, BigRoundy said:

message about battery saving

The State Of Charge will be low.

Fit a new Yuasa battery and change the SOC from 80% to 95% with FORScan

2 minutes ago, unofix said:

The State Of Charge will be low.

Fit a new Yuasa battery and change the SOC from 80% to 95% with FORScan

Thanks unofix!

14 hours ago, unofix said:

The State Of Charge will be low.

Fit a new Yuasa battery and change the SOC from 80% to 95% with FORScan

Battery down at 12.3v after my wife has been driving it all morning...still getting messages about low battery.

Seems like it is time to change it.

On 3/5/2024 at 9:25 PM, Plimp92 said:

Ok.

Unlocked the car tonight. No drls, no interior lights.

Full overnight charge did exactly what we expected.

Now.... can I be bothered to go back to the dealer with it?

 

I have been having the same issues for 2 years. Every time I go back they just keep telling me they can't find an issue. They have changed BMS but that's all I have got out of them. 

Proper fed up with it, not getting another. Going to move to something else. 😕