Unfortunately, battery issues are very common on the MK4/4.5, probably the most frequently reported/most abundantly occurring issue. You are definitely not alone with your problem, just llok for a couple of post here or at other forums/fb groups, you will see.

For some, charging the battery full and resetting it via FORscan resolved the problem, for others a battery swap, better yet upgrading to a bigger capacity battery from another brand solved it. Ford has proven to be quite reluctant with admitting there is an issue, let alone changing the battery. The usual advice from them: No issues with the battery, you just need to drive it more...

classic

 

Had to fit a new and bigger battery to my mk4 yesterday, then in the evening I was presented with this, coincidence (I don’t believe in them):

 

Had to fit a new and bigger battery to my mk4 yesterday, then in the evening I was presented with this, coincidence (I don’t believe in them):

View attachment 917674

You need to use FORscan to set the battery A/H size and then you must do BMS reset or it will never charge properly, the error could well be related to that. Personally I wouldn’t change the battery type, should never be required. Issues with charging are nearly always BMS related as it’s a poor system. A BMS reset or two after a full charge had always 100% solved mine and thats quiet a few.

 

Nope - I ain't a big believer in Coincidences either ................

 

Afternoon

I have had multiple issues with my car which I have shared with the group.
My most recent issue seemed to be a battery problem, flagging on the FordPass app and with previous issues such as the security system failure and this new problem, I raised this with the dealer, particularly referencing other members potential battery concerns as a possible cause.

Ford replaced my battery last week- hopefully time will tell if this was the trouble all along

 

Thanks for the update - How old is the car ??

Question - Does everyone else have a Varta battery installed from new on their 2.3L ST's ??
And do you know what the Manufacturers are quoting for Cranking Amps (CCA) and Battery Capacity (Ah) ??

You need to use FORscan to set the battery A/H size and then you must do BMS reset or it will never charge properly, the error could well be related to that. Personally I wouldn’t change the battery type, should never be required. Issues with charging are nearly always BMS related as it’s a poor system. A BMS reset or two after a full charge had always 100% solved mine and thats quiet a few.

Is FORscan something only Ford Dealers have ?? or is it some type of software you can get or use via the OBD port ??

Soz to be a pain but what is BMS ?? - Ah Googled that its Battery Management System - Yes ??

 

BMS is battery management system.

FORScan is a freely available diagnostic and programming system for Ford cars. You will need to pay for a license to use the programming features.

Ford use a more sophisticated system than FORScan.

 

This is the battery on my 11 month old Focus 2.3L ST - See photo

Surely this is the wrong battery it seems it only has 600 CCA (Cold Cranking Amps) and 60 Ah (Capacity) As a comparison my missus's 1.2L Corsa has a 65Ah battery, albeit I am sure CCA will be less !!!!!

Entering my Car Registration into Euro Car Parts (See Euro Car Part Batteries.pdf) it is showing batteries with 650CCA & 65Ah right up to 760CCA & 70Ah are available for my car

Even Halfords are suggesting a Yuasa 700 CCA & 75 Ah battery for this vehicle ??

What Battery was on everyone else's MK 4/ 4.5 Focus 2.3L ST on delivery from Factory when band new please ??

 

That's the normal battery fitted to the 2.3 ST (same as mine) and it's not really up to the job, so most, including myself, fit the battery Halfords recommend. However by it from Tayna batteries as it's much cheaper for the same thing.

YBX7096 Yuasa EFB Start Stop Car Battery 12V 75Ah | eBay

 

thats the same as mine, mk4.5

 

 

i had problems with mine as it seems the facelift had a smaller battery (ford probably saved a couple of quid) but since i had the charge rate increased its been ok so it will do for now mk4/4.5 battery | Ford Focus ST Forum
if i was keeping it long term then id deffo be fitting the bigger one

 

Hi @Rallyboy548 ... I feel your pain.

Similar boat as you. Love the car, really do. It's so frustrating, such a great package has been put together, then a pointless, cheapness and needless achillies heel has been laid bare with this issue. Your issue - It's all too familiar. same for me... I got to the point, when washing the car I would rapidly clean the inner doors and try and beat the dreaded Ford App messages that 'stuff had been shut down to preseve the battery' .. All because I had opened some doors without the engine running .. I'm sorry, but in 2024, with a car less than a year old... ? Is this really acceptable?

I have replaced mine (battery) today with the Yuasa 096 EFB that comes highly recommened on this forum, supplier websites and the interweb.... BMS manual reset... And the signs..... So far are good. SS working 5 mins after, so SOC should be good - It is a little fiddly as the cold air intake shroud needed to be removed ( two Fordesque clips), with the airbox to allow the 'right battery' to be installed .. For anyone else doing this, the cold air feed and airbox come out as one whole. Also, the 096 battery needs this out of the way to slot in. (Otherwise the insertion angle is too much for the bracket to receice the battery. Be sure to unclip the spacer at the back of the original battery used to adapt the smaller battery into the space... Cables are tight - don't rush it.....

I don't mean to post with any sort of authority on this, but I do feel I want to share my own experience. I waited until my first service to highlight it, with a hope that Ford would resolve the issue - how naieve and wrong was I .....

I still think, battery issue aside, this is such a great car !

Come on Ford! Why do 99% great and then save £20 and create a a £120 - £300 problem and frustrate your customers! Madness!

 

The original battery on my 2008 Mk2 ST lasted for 11 years.... 😛

 

Yes, it seems oem batteries now, aren’t what they used to be, my wife’s 2013 Kuga had to be changed after nine years and my Mercedes was still on it’s original eleven year old battery, until last week, it was still working ok, but I didn’t want to risk being stranded, now it’s winter.

 

I had to charge the battery on our ST yesterday as the low battery warning came up. Two weeks old and just 300 miles on it!
As said above, a 60ah battery on a car with so many electrics??
I am hoping it was just because the battery had run down by being stuck at the dealer for however long. I did ask them to make sure the battery was charged when it was delivered, but would bet money they ignored that.
It took around 6 hours to fully charge on my CTEK (5amp), so was around 50% drained. This is despite the car being driven around 40 miles most weekdays.
I hope this is a one-off, or I will be having words with Ford.

 

Not good to hear, but most owners, myself included, have fitted a bigger capacity battery. The dealer charged the battery on my car, but it’s like filling a leaking bucket up!

 

I fitted a Yuasa 7096 battery to mine. Same type with higher capacity and Ah rating. I also changed the charge % from 80 to 90 using Forscan.

So far, so good. Everything working.

I don't think the standard Ford battery is up to the job.

 

I don't think the standard Ford battery is up to the job.

If it turns out not to be, Messrs Ford MoCo will be paying for a new one, not me.

 

I have had the same issues and have commented on them previously, however I changed my battery back in March for the Yuassa 75Ah 700cca unit and it solved the issues immediately. That proved to me for certain that Ford were being cheapskate and putting in a far smaller battery than what was required. Although it cost me for the new battery it was an easy fix for the issues we have all had.
However, about 6 weeks later I then changed the Target state of charge through Forscan to 95% and then all original issue began again. weird, so put the SoC back to 85 (slightly more than it was originally), but no difference.
So now, even with the larger capacity battery I am back to square one!
I tried disconnecting the battery and giving it a long charge, but that didn't help. I am tempted to do that again, but this time reset the BMS again.
Briefly I was happy with the car, but it didn't last

I didn't change the any other battery setting on Forscan, would it make any difference to change the Ah setting?

 

So back in March I enquired about my battery and the messages on the screen about turning off the radio to save battery power etc, Auto Stop/Start not working and I also noticed the boot light wasn't working and you could not unlock car on passenger side etc
Ford said there was a BMS (Battery Monitoring System, I think) module upgrade (or replacement) available under Warranty and they would do any software checks / updates / tweaks etc that are needed so I took them up on it
Auto Stop/Start worked for about a day and never since
It has been fine for 4 months or so and now messages on the screen about turning off the radio to save battery power etc, can not unlock car on passenger side (until you have done some miles then its fine) have returned again
Anyone else had a BMS upgrade / change etc ??

 

Can’t help with this specifically for focus ST, but I had similar issues with a mk8 fiesta st and if I didn’t drive it for a while (say a week or so) the back windows would go down really slowly, passenger door wouldn’t open with keyless and stop start didn’t work, the only way to sort it was to drive it for 15-20 mins and it all was fine again, so assumed the battery had gotten too low and so by driving the battery was getting some charge and that always worked, it didn’t happen often as I drove it most days. Also there was some kind of reset sequence for the fiesta picking in brake, clutch etc in a certain order and when I did that it resulted in the stop/start working again, no idea if there is a similar thing for the focus?

Do you drive your car regularly? (Not that you should have to!!!)

I now have a 2.5 year old focus ST and most days just do short journeys, say a 3 mile round trip and I haven’t had any issues with the battery so far, though only thing is my stop/start doesn’t ever work, though I do have air con on lots, but I don’t want to use it anyway and would turn it off, so am fine with that not working!!


See here: https://www.fordownersclub.com/forums/topic/121475-focus-mk4-bms-reset/

Though I have no idea when you should do this, so please don’t just do it without understanding what it’s meant for!

 

I had this exact same issue you had, before I had joined this forum my FoST was about 2.5 years old and was getting the messages you had then having to recharge the battery every 4 days, so did some searches and came across a post on this site mentioning the standard battery wasn't up to the job but thought being still under warranty let Ford do some diags and was expecting them to find battery at fault but it passed all the tests. so anyway from a week later I needed to recharge battery every 3 days & thought this is a joke let me check the heavy duty Yuasa option battery mentioned here and as soon it was fitted turned ignition on & did get a quick battery message flash up which I didn't catch what it fully said but car then behaved itself with no low voltage or switching modules off messages so that confirmed the cars electrics were good as dealer was blaming my hard wired dash cam, so problem was the battery afterall.

Now I did see people mentioning you have to do a BMS reset but I didn't reset anything and battery has been fine from august last year until may this year when I needed to hook up to the smart charger to top it up as it's not daily driven at all & after few hours of charging is perfectly fine again, now something I did come across was that the BMS only ever charges the battery to 80% not sure why if thats true.

I think the FoST should have come from the factory with a heavy duty fitted as standard. My stop/start does work if I let it lol, but normally I'm in Sport mode anyway but aircon would stop it working same for having tunes cranked up and was same with my previous Leon Cupra with A/C on and what it will cost you in extra petrol not using it will save you big repair bills on worn out engine components from all the stop start malarky going on.

 

Getting the sleep mode message and the stop start being disabled is not a fault, it is perfectly normal function , all Ford vehicles do it. My car is 5 months old, 6 months from manufacture, only done 400 miles in that period and never had a notification or the stop start being disabled. But importantly I dont have a dash cam bodged into the system which will and does cause issues.

 

I drive my ST once or twice per week and saw that if you turn off keyless entry you gain about three weeks before you get the message remote functions disabled bla bla bla and with they keyless function on about 1.5 weeks