It's possible that the glitches with the electronics and software in the Fabia 4 mc may be partly down to the car battery. I have therefore bought a Ctek CT5 Start Stop charger. We seldom do any long runs and from now on I'll charge the battery once per month to help maintain it. The car has a battery management system (BMS) so it's best if the negative Ctek lead doesn't go to the battery terminal. The Fabia mk 4 is easily upset so avoiding the negative battery terminal ensures it knows that the battery has been charged up.

I decided to fit the included eyelet leads permanently under the bonnet. There's a large cylindrical nut in the engine compartment near to the fuse box and battery with a negative symbol on top. The negative lead eyelet is fitted there. With the positive lead I pushed up the black plastic flap over the battery terminal. Undoing the nut with a small mole wrench was hard work because it was very tight. I put the positive eyelet over the protruding screw thread and replaced the nut. That was the worst part because it was much harder to get the nut back on and tighten it up. I didn't need to disconnect the battery but was very careful not to short anything or drop the nut. You could use just the crocodile clip leads on each charging occasion if it's too much of a fiddle to fit the eyelet cables but remember to use an earthing point rather than the battery negative terminal.

Push in the eyelets leads connector just fitted on to the charger's connector. Plug in the Ctek and as soon as you switch on the mains charging starts. The cable fitted to the charger itself is unlikely to be long enough to reach a mains socket. I've ordered a Ctek 2.5m extension cable to use in future.

The battery charger checks automatically the type of 12v battery, selects the required mode and gets on with the job. After four hours the charger showed a green light meaning a full charge. This charger is very easy to install and use but it'll be a while before we find out if it helps with the glitches.

Hi , I have a C tek battery charger that has 8 stages of charge and find as you say simple to use.

From memory C Tek suggest that you charge the battery every couple of months to keep the everything in order.

Skoda Fabia Mk 4 battery-charging was discussed at some length earlier this month.

This photo was provided showing a CTEK charger connected to the Fabia's battery using crocodile clips.

The small protective plastic cover over the battery's positive has been taken off in order to attach the (red) crocodile clip, but this takes just seconds to remove (and subsequently replace!)

The CTEK CT5 charger is a simplified version of the 8-stage MXS 5.0 charger that I (and I assume super717) use. I find the standard cables that come with the crocodile clip ends long enough to be led out of the engine compartment and for the charger to sit on the top of my Fabia's front-left tyre. (I can then close the car's bonnet.) The 3-pin mains plug at the other end of the cable is pushed under the car out of the rain. I connect a 10-metre cable to the 3-pin plug and lead that cable to the 230V domestic power-outlet in my garage that's next to where I park the Fabia.

A caveat - there is a CTEK CT5 POWERSPORT battery-charger, but this is intended for charging batteries with 5-25Ah capacity range (and includes lithium-iron type).

Edited 29 June, 202529 Jun by DerekU

On 28/06/2025 at 17:08, bazz2004 said:

...The battery charger checks automatically the type of 12v battery...

CTEK advertises their CT5 product as being "fully optimized for cars with Start/Stop technology, e.g. AGM and EFB batteries", but the CT5 does not check the battery 'type' (AGM, EFB, etc.).

CTEK has tended to indicate a charger's maximum output by the charger's product number (eg. MXS 10.0 = 10 Amps), but the output of a CT5 is actually 3.8 Amps.

While the Voltage output of a MXS 10.0 is given as 14.4/14.7/15.8/13.6 V, the CT5's voltage is simply stated as 14.55 V, suggesting (to me) that CTEK has chosen a voltage high enough to charge an AGM battery adequately, but not so high that it might damage other 12V battery types (WET; MF; Ca/Ca; EFB; GEL)

What the CT5 does when connected to a 12V battery and switched on is to carry out a battery 'health check' to confirm whether there's any sort of problem that would prevent it being charged safely/correctly - but that's standard practice for CTEK chargers and not unique to the CT5.

CTEK markets a wide range of battery chargers

https://www.ctek.com/uk/battery-chargers-12v-24v/vehicle-type/car-battery-chargers?srsltid=AfmBOopSDLlG2YGWvbm1qbYsXo3VpXmm7BUeezVsBtLgCKdKKfsMFtyL

I notice that at least one of these (the CS ONE UK)

https://www.ctek.com/uk/battery-chargers-12v-24v/cs-one-uk

can recognise the battery type - but the CT5 does not have that capability.

I often see showroom cars with an indicator lead discretely hanging out of the bonnet, I was told this is a Ctek option.

I use the power socket to plug into for charging and a weatherproof box on the end of my extension lead where

I plug in the Ctek into its socket in the box then sit it under the wheel arch out of the weather anyway, better safe.

Edited 30 June, 202530 Jun by gumdrop

A friend with a just under 2 year sold Ford Kuga, which has an ELB+ doesn't use that car too often, so it has been back to Ford a couple of times for a battery check/charge - it is a personal purchase contract thing car so he feels that Ford should just re-charge/fix the battery, although I have been saying "get a smart charger on it every 2 months if for no other reason than to keep it in a "fit state to avoid any inconvenience".

So, their annual trip to France is happening soon, he became fed up with warnings of low power availability for 12V DC stuff in the car, so finally charged the battery using his smart charger (NOCO) - charger quickly reaches the green/good LED stage, but if a door is opened it immediately reverts to an indicated very low initial state of charge. After stopping charged from an indicated fully charged stage, and waiting 2 hours, the PD across the battery is 12.12V, I said that even although the car starts okay, still limiting auxiliary 12V DC use, I'd be less than happy about driving it a 1000 miles or so to reach my holiday destination. So, eventually he went along to Ford, "battery, if found to be degraded due to lack of regular use, will need replacing and is now not covered by warranty", today it goes in for another boost charge/investigation, I think that in his case, as a former car buyer and fixer/maintainer, the shift to one of these lease/buy schemes has switched him into a "clean hands all car stuff is included" frame of mind, which with his abilities and knowledge, has let him down!

Edit:- I tend to have a couple of CT5s, first one is "TEST and CHARGE" version ie MSX5- possibly not my best buy as the "Test" functionality is a bit limited as even with a new/good/charged battery, when the engine is cranked, the resulting voltage JUST stays within that unit's operating range - any slight weakness in a battery results with it switching off due to the resulting battery voltage when cranking! A basic CT5 bought after I lost confidence in the first one's ability to remain operating as intended, it tended to revert to "min safe voltage" state too often with both cars, so of that was due to it not being able to remember its "last set charging option" as claimed by the operators handbook - now if I need to use, I always select the mode I need even although it is always the same mode. Also have a CTEK Battery Analyser, that woks well, and for using when messing with VCDS, a CTEK PRO25S charger/maintainer/supply.

Edited 30 June, 202530 Jun by rum4mo

1 hour ago, gumdrop said:

I often see showroom cars with an indicator lead discretely hanging out of the bonnet, I was told this is a Ctek option...

This is CTEK's "Comfort" indicator. There are several versions of this and this is a sample advert.

https://www.mdsbattery.co.uk/ctek-m8-comfort-connect-led-indicator-56-382.html

I remember visiting a local Skoda dealership (15?) years ago and all the cars in the showroom had a CTEK indicator poking out of their bonnets. Next time I went there the indicators had gone.

If you GOOGLE-search on ctek comfort indicator useless you'll find plenty of criticism.

I've spotted them in my local Audi emporium, typically sitting on a front wiper arm.

I suppose these "comfort indicators" mainly do do what they set out to, ie give you a vague idea of "how things are" - ie "your charger is still working okay" or where a charger is not fitted "your battery has still got enough charge to stay healthy".

I've never considered buying any of that item, only having 2 cars and enough chargers to cover re-charging batteries has always worked for me, but in car showrooms they maybe save a bit of time - if they work.

The purpose of the CTEK indicator accessory is described here

Criticisms generally are about the relationship between the indicator's three LED lights and the genuine battery voltage.

I remember seeing, for a number of years, dealers using small solar panels, laying in the windscreen/bonnet area, with wires into engine bay. These give a small trickle charge to the battery. My local Kia dealer used them, but that was 13 years ago, so probably not “smart” enough, for modern electrics/electronics.

Thanks for the interesting replies.

Many of us won’t need a charger. If you are located in an urban area where reaching 30mph is a thrill and each journey is a few miles only, it makes sense to use supplementary charging over the winter months. I’m sure DerekU will be able to explain why I’m wrong though.

There was enough info about this charger to know it would be easy to fit and that compatibility with the type of battery wouldn’t be a problem.  There’s no way eyelet leads will be hanging out of the bonnet. These are nice and short, tucked away, ready to connect to the 2.5m extension lead and charger at the end of the month.

There is no detail provided by the charger about the battery after charging it up but that will do fine for me. It starts with an amber light and shows a green diode at the conclusion of the charging cycle.  If nothing else, regular charging should extend the battery life. It will be easy to make this into a monthly routine even in freezing weather conditions.  I’m not on commission from Ctek.

The BMS on my 2019 Polo maintains a max SOC of 83%/85%, presumably to allow room for "more" as the voltage always rises to 14.5/14.8 ish (as per plugged in DVM) on the overrun and then returns to ~ 13.1V. I have a 3.8A Ultimate Speed smart charger but have never used it on my own cars, I will be doing a reasonably long run today of around 55 miles and when I return I will see what the Ultimate Speed does when I plug it in. The readings below were taken yesterday, immediately after the same 55 mile run.

The car has only ~21,00 miles done, all very short but daily runs and I often see the SOC down around 73/75% but the Stop/Start operates fine when I use it, selectively.

IDE01836 Battery current -4.924 A (engine off, ignition on)

IDE01837 Temperature of battery sensor 35 °C

IDE01838 Battery temperature 37 °C

IDE01839 Battery charge level 83 %

IDE01841 Battery internal resistance 8.0 mOhm

IDE01842 Usable battery charge 33 Ah (59AH EFB Battery, original, 6.5 years old)

IDE01843 Battery voltage at rest 12.6 V

IDE01948 Battery internal resistance not normed 5.6 mOhm

This long YouTube video on the Ultimate Speed ULG3.8 B1 charge may be of interest.

My previous car was a 2021 Hyundai i20 that proved to have a starter-battery high parasitic drain.

Assuming that the car's original Yigit Aku (Turkish) dinky little starter-battery was on the way out, I replaced it with a higher-spec Yuasa equivalent.

Assuming (again!) that this would address the SOC loss, I left the car standing for a couple of weeks and, when I came to unlock it using its central-locking key-fob, it wouldn't and, having manually unlocked the car, the starter-battery's voltage was found to be about 10V. I put the battery on charge using my elderly CTEK MXS 5.0 that happily brought the Yuasa battery back to full charge. (So no problems with the CTEK charger dealing with a heavily discharged, but otherwise healthy, battery.)

I keep the Yigit Aku battery in my garage and use it to power my 12V tyre pump. The battery retains its SOC very well and an occasional short blast via the CTEK (when I feel in the mood) brings it up to full charge very quickly.

The man in that video made a classic man mistake - he didn't read the manual (the instructions for the kit he was using) before using it. Like other battery chargers maintainers it doesn't charge batteries when they are below, a stated in the instruction on this unit, voltage.

This charger maintainer probably also had the information on the box it's sold in, perhaps he didn't keep the box, didn't look at the box or just forgot

Lots (all?) of charger maintainers are like this (and there are ways around this without opening it up and dealing with the electronics). The charger had a 3(?) year warranty so if it's faulty he could have returned it before taking it apart. If out warranty of course he can do as he pleases with it. If at the time (YT says posted 6 years ago but that's not always accurate) if he'd lost the paper printed instructions he could have downloaded a pdf copy from Lidl.

'Macho men' (those that don't read instructions) look away now - from the Ultimate Speed Car Battery Charger ULG 3.8 B1 (Lidl IAN 59146) instruction book, note the 3.8v, he set his machine a lot higher than that and his daughter would have had to leave the lights on a very long time to get the car battery down to 3.8v, perhaps she did or left other electrics on too. -

Internet Archive

ULTIMATE SPEED ULG 3.8 B1 Operating instructions : Free D...

Possibly he could easily get a job with VW, looking for something complex (to look "Simply Clever"?) when there's a perfectly good standard basic route that others use successfully. 😄

My CTEK charger is similar - 2.0V minimum battery voltage.

6 minutes ago, DerekU said:

My CTEK charger is similar - 2.0V minimum battery voltage.

And did you obtain that information from using an electronic program load machine or just looking at information given with the Ctek. 🙂

As these "smart" device computer really dumb you can fool it into working on a battery below 2.0V if you want to, how good and reliable that battery would be for actual use and on or with what depends on many factors but it could be done. Some chargers have a very high minimum voltage they don't want to work below so much more scope for batteries with those.

I read documentation...

I have the Ctek One.

My Superb is mainly used at weekends and can be stood a couple of weeks at a time.

As it's garaged I can use the aux socket adaptor with lead through the window.

As the Ctek one is bluetooth you can bring up the voltage and current at any time.

I believe the wake function allows connection to a totally flat battery.

Edited 13 July, 202513 Jul by logiclee

The "CS ONE" is CTEK's premier battery charger.

It's not cheap

https://www.ctek.com/uk/battery-chargers-12v-24v/cs-one-uk?srsltid=AfmBOoqQJQbWNuc7LPVM-Po7DH9GT4cl2Ne_53606fmtiVV7cSoOOwp-

but it should be fairly foolproof and (as logiclee has said) its WAKE UP option is designed to revive shut-down lithium batteries or seemingly dead lead-acid batteries. (Obviously it won't revive genuinely dead batteries, but - unlike less sophisticated chargers - there's no minimum voltage threshold.)

This video

mentions the WAKE UP feature, but does not explain how it works (I expect it's magic!) and there's also this long in-depth 2022 review.

Bennetts BikeSocial Membership

CTEK CS One review | Motorcycle & car battery charger

At £219, this is the most expensive motorcycle and car battery chargers we’ve tested, but do its high current and connected features makes it worth it?

30 minutes ago, DerekU said:

The "CS ONE" is CTEK's premier battery charger.

It's not cheap

https://www.ctek.com/uk/battery-chargers-12v-24v/cs-one-uk?srsltid=AfmBOoqQJQbWNuc7LPVM-Po7DH9GT4cl2Ne_53606fmtiVV7cSoOOwp-

but it should be fairly foolproof and (as logiclee has said) its WAKE UP option is designed to revive shut-down lithium batteries or seemingly dead lead-acid batteries. (Obviously it won't revive genuinely dead batteries, but - unlike less sophisticated chargers - there's no minimum voltage threshold.)

This video

mentions the WAKE UP feature, but does not explain how it works (I expect it's magic!) and there's also this long in-depth 2022 review.

Bennetts BikeSocial Membership

CTEK CS One review | Motorcycle & car battery charger

At £219, this is the most expensive motorcycle and car battery chargers we’ve tested, but do its high current and connected features makes it worth it?

Over the years I've had MSX 5.0, 7.5 and 10.

Started with the 5.0 and then bought the 10. 10 was too powerfull for the 12V socket adaptor so swapped that for the 7.5.

I used the 7.5 for a couple of years until the One came out.

I watch most of the youtubers with big car collections Shmee150, Harrys Garage etc and they all use CTEK. I think I first saw the Ctek One on Shmee150's channel. If they are happy using them on cars worth 7 figures then that's good enough for me.

Also appears that brands like Ferrari supply re-branded Cteks.

I bought the wall mount bracket for the Cteck One and have it permanently mounted on my garage wall and it conveniently doubles as a cable tidy.

It's about two weeks since I fully charged the battery with the CTEK ct5 start stop. I hoped that keeping the battery fully charged would remove all the glitches, particularly the way the display changes itself. With that there has been no improvement and the display has changed twice. Maybe it's my wishful thinking but I think the car runs a bit more smoothly.

I bought a battery tester (Ancel BST60) for around £13 to get a bit more detail. This plugs into the cigarette lighter power socket in the arm rest using a short lead. It shows 12.1v after a fortnight of very little driving. It looked about the best of what was available at a cheapo price. It has a setting for checking whether the alternator is putting in a sufficient charge.

The auxiliary (cigarette) power socket on mine is only live with the ignition on, not much use really, also the DRLs (daylight running lights) are then also on with a total battery demand of 4.8A. My £20 charger is a Ultimate Speed ULGD 5.0 C1 (5amps max) and has a volt meter, it seems reasonably smart, I attached it 2 hours after my 50 mile trip today, it read 12.8V and after switching on went to 14.4V for a few minutes and then settled at 13.5/13.6V trickle charge?. These type of chargers are really only battery tenders but should do the job quite well IMO to maintain any battery during infrequent car use.

Edited 13 July, 202513 Jul by Johngerard

48 minutes ago, bazz2004 said:

It's about two weeks since I fully charged the battery with the CTEK ct5 start stop. I hoped that keeping the battery fully charged would remove all the glitches, particularly the way the display changes itself. With that there has been no improvement and the display has changed twice. Maybe it's my wishful thinking but I think the car runs a bit more smoothly.

I bought a battery tester (Ancel BST60) for around £13 to get a bit more detail. This plugs into the cigarette lighter power socket in the arm rest using a short lead. It shows 12.1v after a fortnight of very little driving. It looked about the best of what was available at a cheapo price. It has a setting for checking whether the alternator is putting in a sufficient charge.

Swap the battery

Wifes Skoda Octavia was doing wierd things for a couple of months. Displays changing, cooling fan running when cold and aircon off, radio swapping channels.

I'd condition the battery and it would be OK for a few days but then acting up again.

Alternator tested OK.

New battery has solved everything.

One of these Digital Volt Meters (DVM) that plug in to the auxiliary power socket give a permanently useful indication of battery voltage/Alternator smart charging etc.

19 minutes ago, Johngerard said:

One of these Digital Volt Meters (DVM) that plug in to the auxiliary power socket give a permanently useful indication of battery voltage/Alternator smart charging etc.

Yes, I agree, I've had one for maybe 16 years, possibly would get "unsettled" if I left home with it accidentally left in our other car!