[Bdenhow]

Bought a new UK model i20 Premium 48v mini hybrid at the end of June. ISG worked briefly Cruise Stop Start CSS only worked one day we took a run of 50 miles then neither worked for weeks.
Car needed a specialist technician (he was on holiday I was told) so 6 weeks later it went in and I was told the car battery was at 75% too low for these to work. You would think they would charge them up for delivery. I got it back after a day on charge and both worked immediately and frequently. Heaven!
However after parking for an hour on the way home the CSS hasn’t worked since. ISG is OK so far.
I guess I need to drive more having done mostly local trips in its 580 miles so far.
The 48v feature is new on i20 here but is installed on other models so has anyone had similar issues?

 

[Harry20]

Hi. I have exactly the same problem !! The only time it works is when I do a long drive of over 100m with over 90% on a motorway. Today I drove (daytime) over 60 miles with 75 % on a motorway and it still did not work. When i got home the Bluelink app showed a caution against the battery. My car has done 4.5k miles and it has never worked differently.
This cannot be acceptable. Stop start technology has been around for years and other vehicle makes with this facility do not behave like this. I dont believe that potential purchasers of the new 24V i20 are told that you have to drive over 100 miles down a motorway to get the stop/start/sailing to work and if you leave it overnight it won't work in the morning. I was not told this and the car will be going back to the dealers to sort out. I'm not happy.

 

[Bdenhow]

Harry
i demanded a new under bonnet battery, got it and both features worked fine within 5 miles. For the last month the car hasn’t done many miles but stop start works fine still. Hoping the CSS will kick in when I do a longer journey. Now got clutch judder problems though!!!

 

[Harry20]

Hi. Im going to demand a new 12volt as well when it goes in. Hopefully that will work. Don't mention clutch judder. I got a very brief spell of it today pulling away from cold. Seems from other posts it's a possible i20 problem . Glad to hear the battery change in your car sorted the problem. Gives me a bit of hope.

 

[Bdenhow]

My car was pre registered and I suspect had been in a car pound for ages before I got it. The demonstrator had a flat battery. I had to wait a month for the Hyundai garage to have a Hyundai technician in to fix it. They charged it up, it all worked for two hours till I parked up and never worked again. So I demanded a new one and the sales manager agreed.
my Stop start worked ok today after 3 miles though the car hasn’t been used all week.
Good luck.
There’s reports of clutch judder and failure on i20s since 2009, I started a new thread on that today Mine seems to be related to dampness in the atmosphere when I first start off in the morning, My daughter has a 2019 play i20 and it had the same problem. She’s getting it fixed under warranty with a new part. Waiting to hear what it is to get mine done.

 

[Harry20]

Strangely enough my car was a pre reg. I bet my car suffers from the same possible problem as yours did. I will bear all what you have said when I contact the dealers. Again i had minor judder when first pulling away this morning.

 

[potblack2win]

Strangely enough my car was a pre reg. I bet my car suffers from the same possible problem as yours did. I will bear all what you have said when I contact the dealers. Again i had minor judder when first pulling away this morning.

I'm suffering exactly the same issue where ISG only works once a week. My daily commute is on 6 miles to and from work.

My car was a pre reg aswell but was a demonstrator car and had 189 miles on it. I drove 120 miles from Birmingham to London and ISG worked fine. The next two weeks or so didn't really drive that car long distances as I was waiting for someone to fit front parking sensors to vehicle. Will a new car battery fix the issue?

Also when I start car the RPM tachometer needle moves when idling slighting but stabilises it self somewhat after 20 minutes of driving. Anyone else experienced this problem?

 

[Harry20]

Hi again. My car is now at the dealers waiting for a new battery under warranty. In my opinion there seems to be a possible problem with the batteries ( under bonnet 12v ) if the battery gets heavily discharged or runs flat. The battery seems to have a problem getting a full charge or retaining it. I am driving a 2 week old Byon curtesy car and I was gob smacked how well the stop start/start and sailing worked and how often and quickly they operated after starting from cold.

 

[Harry20]

Just an after thought. There may be a potential problem if the car had been jump started. The garage was very interested if that had happened. Just to say it had not but could it cause a problem with these batteries if it had. Another comment is that owner could not change the battery themselves as the system has to be 're calibrated and this takes 4-6 hours. Or so I'm told.

 

[Harry20]

Good new. The 12V battery was replaced under warranty. The stop start and sailing
Now works perfectly.

 

[Bdenhow]

Good new. The 12V battery was replaced under warranty. The stop start and sailing
Now works perfectly.

Great a new battery fixed mine too. The clutch judder has continued, recently had a Check 48v battery warning. No mention of this in the handbook in fact no mention of the 48 battery. Was advised not to drive it no Hyundai garage could take it for 6 weeks so Hyundai assist couldn’t give me a lease car. phoned manager who agreed to put car on my drive and sanction a lease car. I’m told 6 weeks of a Mini Cooper cost over £1000 a week. Had the car fixed on May 30th only to find it reappeared today.
Garage told me this time if it was an amber triangle it was safe to drive, a flashing or red one wasn’t. So it looks like it needs another visit. I wrote to Hyundai about the handbook, the clutch the ISG and CSS and this new one and handbook. not sure what the garage did at the service but it needed a new battery module which took a month to get.
Demoralising!

 

[DLUi20]

This is just idle curiosity...

When I first looked under the bonnet of my 2021 Hyundai i20 SE Connect, I was surprised by the smallness of the factory-fitted 12V battery given that the car has an ISG system (Idle Stop & Go). I had anticipated something significantly 'meatier' and probably AGM or EFB type, but what's there is just a common-or-garden little 45Ah battery marked CMF45L-DIN(12V) and made by the Turkish company Yigit Aku.

What is (slightly) interesting is that this webpage relating to the Kia Rio

Kia Rio: Specifications - Battery - Charging System - Engine Electrical System - Kia Rio UB 2012-2022 Service Manual

indicates that a CMF45L 45Ah battery was used for Rio cars without an ISG system, whereas those cars with ISG had an AGM 70L 70Ah battery. The dimensions of the Yigit Aku 45Ah battery are 207mm x 175mm x 190mm (Length x Width x Height), whereas batteries with a width and height of respectively 175mm x 190mm would have a length of 242mm (60Ah) or 278mm (70Ah). I haven't accurately measured what maximum length of battery could be shoehorned into my i20, but a 242mm battery should certainly fit and probably a 278mm one.

So - if your i20's 12V battery was replaced under warranty - was this done on an exact like-for-like basis (ie. presumably another Yigit Aku 45Ah battery was fitted) or was a different make/size battery installed?

(A neighbour has a 2016 i20 Active and, while she was travelling abroad for several months, I kept an eye on her car. I remember - when I checked the Active's 12V battery's state-of-charge (SOC) - that the battery was a sizeable AGM type and I subsequently found that its SOC degraded very little during the time the car was out of use. I charged up the battery shortly before my neighbour returned home, but there was really no need.)

 

[Bdenhow]

Sorry but I have no idea what battery went in.
Don’t think I ever looked at the battery - before or since.
I’m getting rid of it after issues with clutch judder unresolved after 6 months as they need to see it themselves and it only does it when it’s cold or wet and most recently a Check 48v battery warning has appeared which took 6 weeks to be seen, four weeks to wait for a new module only for it to appear again a week later in early July. I can’t get it seen till August 26.
Now it’s disappeared!!

 

[Bdenhow]

The battery in it is
DP370APU044CHOU 44Ah 360AEN
No maker
Hyundai genuine parts

 

[DLUi20]

Thanks for identifying the replacement battery that was installed in your i20.

It seems that this 12V battery is commonly fitted to EV models where it provides the power source for the 'management' of the vehicle's electronics.

This 2020 SpeakEV forum thread refers

FFS Failed 12v Battery already...

and there are (on Page 2 of that thread) photos of the 44Ah battery that I've copied below.

And this 2018 Hyundai IONIQ forum thread queried the size of the 40Ah battery that was apparently fitted as standard to that model.

Does the Ioniq EV need a larger 12V battery?

There is a critical difference between the requirements of the 12V 'management' battery in a Hyundai EV and the starter battery of an i20 mild-hybrid. The CCA (Cold Cranking Amps) of my car's Yigit Aku 45Ah battery is given as 330A (EN) and the CCA of your replacement 44Ah battery is 360A (EN) - so there's not much difference CCA-wise. However, a good quality (eg. Bosch, Varta, Yuasa) EFB 'Start/Stop suitable' battery with dimensions of 242mm x 175mm x 190mm (Length x Width x Height) would have a CCA of over 600A (EN) with an asking-price from around £90 - and the higher the CCA the better when it comes to starting power.

I suspect that - if the original Yigit Aku 12V battery in my i20 were replaced free-of-charge under warranty - I'd accept the 44Ah Hyundai-marked battery. But if I needed to replace the Yigit Aku 45Ah battery and pay for the replacement, I'd probably opt for an EFB-type that was 242mm long.

 

[Harry20]

Hi. Just to mention. Probably the new i20 has a starter / alternator combo unit and not a conventional bendix flywheel starter. It would start the engine via the engine front belt. That's why it is very quiet when it operates.
.

 

[DLUi20]

Hyundai 'mild-hybrid' i20 cars have a conventional 12V battery, a 48V lithium-ion battery and a Mild Hybrid Starter Generator (MHSG). The mild-hybrid system was described in this 2019 Hyundai press release that related to the Tucson model but the principles apply similarly to i20 MHEV cars.

Hyundai 48-Volt Mild Hybrid System

I don't know if the i20's mild-hybrid system fully justifies having having such a small 12V battery (saving weight and potentially cost) but the battery tray of my i20 looks like it is designed to accept a longer battery.

It's possible that diesel-fuelled 'new' i20s marketed outside the UK (or petrol-fuelled i20s marketed in countries that have very cold winters) have a larger battery and that the tray is designed for such vehicles - but that's just supposition...

 

[5656]

Does anyone know what 12v charger would be best to use on my 2021 n line 120ps Reg. VK21MHL

 

[DLUi20]

That's rather like asking which is the best new i20 model...

The current UK Recommended Retail Price for a new i20 extends from around £19K for an SE Connect to over £25K for an i20N. If a buyer is looking for 140mph performance the i20N will provide this, but it's going to cost: if a buyer just needs a fuel-efficient 5-door hatchback, the significantly cheaper SE Connect will do. Choosing a battery-charger is similar - it depends on what it's to be used for and how much one is prepared to pay.

For quite a few years I've used a CTEK MXS 5.0 battery charger (sample advert here)

CTEK MXS 5.0 Battery Charger

to maintain the charge state of my vehicles' starter battery when the vehicle has been out of use for an extended period, and that's what I use for my i20. This photo shows my car's battery, with a CTEK 'eyelet' attached to it that allows my charger to be connected easily.

The Hyundai Owner's Manual includes battery-related guidance in Chapter 9 and advises as follows regarding recharging.

"The battery must be removed from the vehicle and placed in an area with good ventilation."

As I'm going to charge the battery without disconnecting/removing it (and given all the i20's techie electronic stuff) I do try to minimise potential problems resulting from battery-in-situ recharging. So - before switching the charger on - I ensure that the car is unlocked and that all its doors, bonnet and boot are shut. I also allow at least 10 minutes to elapse after those 'openings' have been shut before charging begins. These precautions should be enough for the car's electronics to become quiescent and, so far, my i20 hasn't taken offence.

An alternative to a CTEK product would be a Victron Energy charger.

Chargers - Victron Energy

Also not cheap and CTEK or Victron (and i20s) the higher the power output the higher the price.

 

[5656]

That's rather like asking which is the best new i20 model...

The current UK Recommended Retail Price for a new i20 extends from around £19K for an SE Connect to over £25K for an i20N. If a buyer is looking for 140mph performance the i20N will provide this, but it's going to cost: if a buyer just needs a fuel-efficient 5-door hatchback, the significantly cheaper SE Connect will do. Choosing a battery-charger is similar - it depends on what it's to be used for and how much one is prepared to pay.

For quite a few years I've used a CTEK MXS 5.0 battery charger (sample advert here)

CTEK MXS 5.0 Battery Charger

to maintain the charge state of my vehicles' starter battery when the vehicle has been out of use for an extended period, and that's what I use for my i20. This photo shows my car's battery, with a CTEK 'eyelet' attached to it that allows my charger to be connected easily.


View attachment 475143

The Hyundai Owner's Manual includes battery-related guidance in Chapter 9 and advises as follows regarding recharging.

"The battery must be removed from the vehicle and placed in an area with good ventilation."

As I'm going to charge the battery without disconnecting/removing it (and given all the i20's techie electronic stuff) I do try to minimise potential problems resulting from battery-in-situ recharging. So - before switching the charger on - I ensure that the car is unlocked and that all its doors, bonnet and boot are shut. I also allow at least 10 minutes to elapse after those 'openings' have been shut before charging begins. These precautions should be enough for the car's electronics to become quiescent and, so far, my i20 hasn't taken offence.

An alternative to a CTEK product would be a Victron Energy charger.

Chargers - Victron Energy

Also not cheap and CTEK or Victron (and i20s) the higher the power output the higher the price.

Thank you so much for your extensive support, I have just ordered the CTEK 5.0 charger and it will arrive tomorrow.
I will let you know how I get on, once again, thank you