2 hours ago, Nout said:

Just doesn’t seem right, maybe the car just wasn’t for them.

It does happen that people buy a car that just isn't right for them. Ask me how I know 🤣

1 hour ago, unofix said:

It does happen that people buy a car that just isn't right for them. Ask me how I know 🤣

I'm sure we've all done it at some time! I've certainly parted with a few mistakes asap.

I purchased my Mk4.5 from a Ford main dealer. Their own demo car, so I'm now the second owner. 

The "low battery" warning message came up within a couple of minutes into the test drive!  Salesman said "don't worry about that" .... well he would, wouldn't he?!

Anyway, I said I was worried so he said they'd  charge it before i took delivery, and all has been okay since.

Very occasionally Ford App tells me the car is going into battery saver mode.  But it always starts next time I go to use it, so it doesnt bother me now.

It's only since I've been reading this forum that I now know why it happens.  Thanks to everyone for their advice and experiences. 

I love the car.  It's a joy to drive.

Just to give an update.. I spoke with the dealer today and the reason for the additional registered keeper was that the car had been returned to them within the 14-day period due to rodent damage to the electrics.

Although this has now been repaired, based on my experience as the director of a pest control company.. once this type of damage has occurred it can often lead to ongoing issues.

As a result, I’ve decided to withdraw from the purchase. Disappointing, but ultimately the right decision. We’ve instead chosen to go with a Kia Proceed GT-Line, primarily for the 7-year warranty and its overall reliability.

On 1/18/2026 at 1:48 AM, captaincadet said:

Lovely car!

 

honestly there isn’t much you can do. It seems that Ford has underspecced the battery on these cars (I believe it’s a problem on kugas and pumas too).

If you have access to forscan, change the state of charge to 95% (though don’t tell the garage this). If you’re having battery issues (including fordpass) try to get the garage to change the battery. They’ll probably put the same (underspeced) battery back in.

Others have put bigger batteries in with success. I have the same OEM battery replaced (garage wasn’t interested in the issue being the battery too small) and I found in the cold it’s turned off the FordPass connection after about 2/3 days but otherwise in the warmer climate it’s fine 

The battery isn't underspecced, an AGM battery would have behaved much better than the standard EFB. Using a larger battery only makes the issue easier to live with. If you read my previous posts in the same thread you will find that the issue can actually disappear and that the behavior can become "normal" even with the EFB battery. At least on Automatic 155hp MHEV, don't know about other variants. 

I have a Focus Active 1.0 155hp mHEV. My issue is the mHEV goes haywire in cold weather. The electric assist doesn't work anymore. Or sometimes it does work, but only if I press the accelerator really deep. The regen icon however works completely normally every time I decelerate. But there seems to be no logic with the assist whatsoever.

The winters around here are typically around -5°C down to -15°C. Although exceptions either way are normal.

The 12V battery has been replaced once at the dealer last spring (they installed the same factory model underspecced 60Ah battery). That seemed to remedy the problem at the moment. But in retrospect, I believe the warming weather at that same time had something to do with it.

This winter the problem started again. Disappointed by the lack of enthusiasm from Ford's side, I bought a Yuasa 70Ah AGM and changed it myself. That sadly didn't fix the problem, but at least I probably won't be getting those low battery warnings as I did last winter.

I got the old battery out fairly easy and managed to shoehorn the new one in without removing the air box. Just pushed the airbox on its rubber mounts and the battery went in.
The factory mounted battery is shorter than the replacement battery and there was a spacer in the tray that needed to be removed before the new one went in.

The problem with my non-working mHEV still persists, though. What on earth could it be?

Just felt my mHEV battery and it gets quite warm. Even in the winter (-12°C). Measured 35°C on top of the battery casing after half an hour’s drive in the city.

The electric assist worked a little bit better towards the end of that drive, but still didn’t kick in when starting from a stand-still.

On 2/13/2026 at 10:20 AM, Don MC said:

Disappointed by the lack of enthusiasm from Ford's side, I bought a Yuasa 70Ah AGM and changed it myself. That sadly didn't fix the problem, but at least I probably won't be getting those low battery warnings as I did last winter.

I got the old battery out fairly easy and managed to shoehorn the new one in without removing the air box. Just pushed the airbox on its rubber mounts and the battery went in.
The factory mounted battery is shorter than the replacement battery and there was a spacer in the tray that needed to be removed before the new one went in.

That’s interesting to note that you managed the battery change without removing the air box. I’ve been wondering how straightforward an upgrade would prove to install and assumed it would be fiddly removing the air filter assembly.

Why an AGM rather than the usual EFB? Most others on these forums recommend the Yuasa YBX7096 EFB as an upgrade.

Back in ‘Battery Saver mode’ myself. Didn’t use my Focus much other than a short shopping run this week so back on trickle charge. Oh the joy of owning a modern Focus. Interesting, or new to me, that battery saver mode continues to display (on remote Ford app) even though the battery is now fully charged. Software is not clever enough to change status until car is started.

Hi Mike, the EFB Yuasa is not an upgrade, it is a replacement. I changed my Varta for the Yuasa in May 2024. Haven't had any issues with deep sleep since then. Charge state is always between 70-80% (usually I find it around 75-77%).

However, this is for the pre-facelift. Whatever is draining the batteries in face lift models, is missing in pre-facelift. So itis hard to tell how well the EFB Yuasa would handle this constant draining.

I chose AGM over EFB because I've read that AGM batteries perform a bit better in the cold. Especially when it comes to recharging after a cold start. Even if it's just a little bit, it might be enough to avoid those Battery Saver Modes. At least together with the slight step-up from 60Ah/600A to 70Ah/760A.

I have a small voltmeter in the cigarette lighter outlet and it shows me the charging circuit is working differently now. There clearly are a lot more variations in the charging routine now than before. Before, it just stayed on 14,5V all the time. As if the battery was struggling with receiving a charge.

2 hours ago, mad-mushroom said:

Why an AGM rather than the usual EFB?

AGM can take higher charging current from the battery charging system. This means that if your driving profile is made of "mostly short trips", therefore less charging time, then the use of an AGM battery, with updated charging parameters favoring higher charging current, will make the issue appear less often.

56 minutes ago, Don MC said:

I chose AGM over EFB because I've read that AGM batteries perform a bit better in the cold. Especially when it comes to recharging after a cold start. Even if it's just a little bit, it might be enough to avoid those Battery Saver Modes. At least together with the slight step-up from 60Ah/600A to 70Ah/760A.

Did you make any battery type changes to the Forscan settings, e.g. EFB to AGM? Also, had you tried updating the target state of charge from 80 to 95%? Changing the later has definitely helped to reduce the frequency of battery saver mode activations for me – other than where I give my Focus too much time off!

Just now, mad-mushroom said:

Did you make any battery type changes to the Forscan settings, e.g. EFB to AGM? Also, had you tried updating the target state of charge from 80 to 95%? Changing the later has definitely helped to reduce the frequency of battery saver mode activations for me – other than where I give my Focus too much time off!

Nope. Just the BMS reset (5x high beam, 3x brake pedal). Car is still under warranty, so I didn't want to do anything that would affect it.
Had I done those changes with Forscan, then I prob wouldn't have had to change the battery in the first place.
The original battery is still in working order. It's just not sufficient with those stupid factory parameters in place.

E: There are instructions for changing the battery in the owner manual, so I figured Ford will allow for the owner to do that job. There are however no instructions for changing any parameters with Forscan, so I figured that could void the warranty.

11 minutes ago, Don MC said:

Nope. Just the BMS reset (5x high beam, 3x brake pedal). Car is still under warranty, so I didn't want to do anything that would affect it.
Had I done those changes with Forscan, then I prob wouldn't have had to change the battery in the first place.
The original battery is still in working order. It's just not sufficient with those stupid factory parameters in place.

OK, thanks for clarification. I had presumed it would be necessary to tweak the BMS programming when changing to AGM (from the preset OEM EFB type battery). Could you share the model number of the Yuasa AGM battery that you used? Presumably it is the same dimensions as the often used YBX7096 EFB.

Just now, mad-mushroom said:

OK, thanks for clarification. I had presumed it would be necessary to tweak the BMS programming when changing to AGM (from the preset OEM EFB type battery). Could you share the model number of the Yuasa AGM battery that you used? Presumably it is the same dimensions as the often used YBX7096 EFB.

Yuasa YBX9096 AGM 70Ah/760A
LxWxH: 278 x 175 x 190 mm
It says "Made in Korea".

A bit larger and far heavier than the puny original:
Varta K1BT-10655-AA EFB 60Ah 600A
LxWxH: 238 x 175 x 190 mm

10 hours ago, mad-mushroom said:

Interesting, or new to me, that battery saver mode continues to display (on remote Ford app) even though the battery is now fully charged. Software is not clever enough to change status until car is started.

I believe you will need to start the engine following the charge as the communication from the car to the app has basically gone to sleep to save battery usage.

12 hours ago, mad-mushroom said:

Back in ‘Battery Saver mode’ myself. Didn’t use my Focus much other than a short shopping run this week so back on trickle charge. Oh the joy of owning a modern Focus. Interesting, or new to me, that battery saver mode continues to display (on remote Ford app) even though the battery is now fully charged. Software is not clever enough to change status until car is started.

You used to be able to refresh the App by swiping down and you could get for example up to date Tyre Pressures, live tracking etc but Ford took away that ability a few years ago☹️

On 2/16/2026 at 11:30 AM, EmilC said:

AGM can take higher charging current from the battery charging system. This means that if your driving profile is made of "mostly short trips", therefore less charging time, then the use of an AGM battery, with updated charging parameters favoring higher charging current, will make the issue appear less often.

This may have been previously posted, but just as a cross-reference to recent discussion in this thread ... herewith useful web refs to changing the Ford Focus EFB battery to AGM. Although in German (mine is really not very good, so subtitles deployed) this outlines the process of changing the Focus battery and revising associated settings in Forscan.

My Ford Focus MK4

My Ford Focus MK4 - Changing car battery from EFB to AGM

The Ford Focus MK4 comes with an EFB battery as standard, measuring 278 x 175 x 175 mm. For anyone who wants to install an AGM battery, there are instructions in the video below. AGM batteries are usu

Something I won't do until the warranty runs out as I see switching from EFB to AGM via Forscan as an obvious void warranty problem if discovered (and I'm not lucky at the best of times)