Do other people have to keep on charging the battery on a weekly basis we use the car on a weekend but then it can stand for 4 days not used , its a 2024 focus St line X mhev just taken it to bristol street motors who say the 60ah battery is correct one and charging is right so frustrating we make sure nothing is left on dont use heated seats etc 

 

 

15 minutes ago, Nidge55 said:

Do other people have to keep on charging the battery on a weekly basis

Hi Nigel, welcome.

The short answer is "yes". If you have a good look round the site you will find several long running threads on the issue with Mk 4 Focuses, Mk 8 Fiestas and Pumas for those of us who use our cars on an irregular basis.

 

 

 

39 minutes ago, Eric Bloodaxe said:

 

 

Hi Nigel, welcome.

The short answer is "yes". If you have a good look round the site you will find several long running threads on the issue with Mk 4 Focuses, Mk 8 Fiestas and Pumas for those of us who use our cars on an irregular basis.

 

 

 

Thanks for reply 

do u think the 60ah battery is large enough as the car has powered boot lid and many electrical extras looked at a few threads where people have upgraded the battery but will that require coding ?

1 hour ago, Nidge55 said:

do u think the 60ah battery is large enough

No.

The amount of extras plays little part in what extra capacity you need.

Many owners of the petrol engined Focus have replaced the battery for the one used by the Ecoblue 2.0 which is a much larger capacity. Also using the software FORScan the battery State Of Charge can be changed from the factory default of 80% and increased to 95% which make quite a difference.

Fit the Yuasa battery YBX7096  75Ah 700A EFB Start/Stop battery as used by the EcoBlue engines. Also get the SOC set to 95%

 

That☝️☝️☝️

Just had my battery replaced for a 70ah VARTA. Unbelievably the factory fitted 65ah lasted 5 1/2 years and 75k miles !!! I think using it every day (no holidays for me) is the difference. Can’t believe Ford are still fitting batteries that aren’t good enough. About to trade the focus in ,thankfully RAC fitted it roadside. I’ve had a blast driving that motor ! Hoping the next one will be even better. 

 

 

You have to get into a new mindset for modern cars. On my old Nokia 6210, I could easily get 14 days use from a single charge. Obviously it didn't have much functionality to drain it. Compare it to a modern smartphone which most struggle to get a full day of use out of.

New cars have so much cr*p in them, with sensors/modules/functionality that they have developed way beyond the battery technology they've been fitted with.

Most on here will regularly now own a 'smart' charger which they use at least monthly to ensure their car has a fighting chance to operate close to what they expect from their new modern, all singing, all dancing fully loaded car.

I get your point but LED lights use a fraction of what power halogens use. The touchscreens probably use less power than a CD player. I’m no sure about air con but probably evolved too. 🤷‍♂️ That said heated seats and auto climate control will probably eat into my EV range. I only do short journeys so no really caring much. 

Took my 2023 Focus ST Line X MHEV in to Ford dealer six days ago to fix the air con which was blowing warm. Said they needed to keep it overnight to fully charge the battery and then perform software updates in the morning. Been getting low battery warning on dashboard last couple of mornings, which I wasn’t getting before. Use the car every other day on average.

18 minutes ago, trebor2 said:

Took my 2023 Focus ST Line X MHEV in to Ford dealer...

Did the battery charge sort the A/C out?

Wondering if I should get the battery swapped under warranty, as mentioned elsewhere on the threads? If that will make a difference.

1 hour ago, StephenFord said:

Did the battery charge sort the A/C out?

Yes, so far!

16 hours ago, trebor2 said:

Wondering if I should get the battery swapped under warranty, as mentioned elsewhere on the threads? If that will make a difference.

I would invest in an inexpensive 'smart' battery charger, and set a monthly alarm in your phone to charge your battery. This will be far more reliable than swapping out your battery every few months!

Something like this would be more than adequate...

Does driving in sport mode charge the battery quicker than eco or standard modes?

On 8/10/2025 at 5:43 PM, trebor2 said:

Does driving in sport mode charge the battery quicker than eco or standard modes?

No, it makes no difference.

The BMS is programmed to mostly charge the 12V battery on engine 'over run'. In other words when the engine is slowing down. Driving in sports mode will increase the engine RPM while driving but will not charge the battery until you lift off the accelerator and allow the car to slow.

This is the reason that doing long runs at high speed on a motorway is less effective at charging the battery than doing lots of stop, start driving at low speed around town.

From my limited experience of driving MHEVs on test drives, using Sport seems to increase the amount of regen braking and thus, I assume, benefits the 48v battery. Owners report similarly.

This reminds me that I've never found a really good explanation of the battery charging "pecking order" on MHEVs, FHEVs, or indeed full EVs.

There's lots on the MHEV system, including Ford's own video below, but little on the 12v aspect. I see from other forums that many Toyota hybrid owners, for example, are baffled as to how their traction battery can be fully charged, but the 12v is flat.

 

15 minutes ago, Eric Bloodaxe said:

... are baffled as to how their traction battery can be fully charged, but the 12v is flat.

James May has a lovely YouTube on the issue of his Tesla 12v battery going flat!

 

54 minutes ago, StephenFord said:

James May has a lovely YouTube on the issue of his Tesla 12v battery going flat!

Thanks Stephen. That's a very clear explanation of the issue. Presumably the same applies to other EVs?

Rather stupid of Tesla to make it so difficult to deal with, though!

3 minutes ago, Eric Bloodaxe said:

Rather stupid of Tesla to make it so difficult to deal with, though!

Indeed, there's a car that needs a MayPole 🤣

1 hour ago, Eric Bloodaxe said:

Rather stupid of Tesla to make it so difficult to deal with, though!

Not really.  Cars are designed to be driven.  Not parked in a garage unused for months at a time.  

Sorry Tom, you've disappointed me with that comment. I hope it's just tongue in cheek.

1. There is absolutely no excuse for the designers making it so difficult to access the battery terminals.

2. Their explanation of why the 12V battery doesn't get charged is b*ll*cks. It's perfectly possible for the charger in the car to detect the SOC of the 12V battery and divert a trickle charge to it when the main battery is fully charged and still connected to the mains charger. The 12V battery must get charged from the main one in normal operation anyway so why would any designer think it's ok to stop maintaining it when the car is not in use?

My ICE cars have broken more parts since they've been left unused than when they were being driven.  That isn't the manufacturers fault.  I get fed up of seeing people abuse cars like that and then complain that the battery is flat or the rubbers have perished or the oil has degraded.  Cars are designed to be driven.  It takes a huge amount of resource to manufacture one, no-one needs garages full of them, that's a choice they've made, same as the choice I've made not to sell or scrap so far...

12v batteries shouldn't need easy access if the car is driven properly and the charging software is correct.  There were issues on a few early EV's not charging the 12v battery from the traction battery while parked, but that was easily rectified with a software update.  It's not so much of an issue now as far as I'm aware.

The MHEV battery on Fords doesn't hold charge long term, so it wouldn't be worth trying to charge the 12v battery from that one while parked.

Its certainly not a good idea to leave cars undriven, but unfortunately in life stuff happens. At one point I couldn't drive for well over 12 months due to serious injury, not through choice. Fortunately it was possible to easily open the car and access the battery, unlike Teslas effort, it seems.

What we don't know from the James May video (unless I missed something - it has been known😀) was exactly how long the car had been left. I only picked up James saying "a while"?

 

6 minutes ago, Eric Bloodaxe said:

Its certainly not a good idea to leave cars undriven, but unfortunately in life stuff happens.

During 'lockdown', my mums car was left in excess of 6 months (8?) without being touched, and when I did get round to starting it, the thing fired up on 1st twist of the key. Of course it's a 2003 Toyota Yaris, so I would have been surprised if it hadn't... 😁