Mark-Surrey

I called Skoda today to book my 1.5 DSG in for its 5-year service, and they also informed me that it’s now recommended to change it after 140K miles. It was a very pleasant surprise, considering it’s only done a very low mileage

No, I changed it on December 13th

For those of you who were wondering whether my battery really was reaching end of life, or whether it was perhaps the BM2 battery monitor itself which was draining the battery, here’s the answer, from a screenshot which I took this morning in the BM2 app. You can see that since I changed the battery a couple of days ago, the daily drop in voltage is significantly less than it was with the old battery. I haven’t driven the car during the previous 2 days. The temporary dips in voltage were when I simply opened the car door, in order to pop the bonnet open.

Thanks @Kenny R! All sorted now, with your kind assistance

Thanks for your sound advice. I just checked, and you are absolutely correct. They have connected both the battery monitor cable and the CTEK charger cable to the negative battery post. Can I just attach the negative CTEK charger lead to one of the posts underneath the metal bracket where I would normally attach the crocodile clip? From what I can see, the CTEK lead is currently attached to the negative battery post using a secondary nut, so I should be able to move it without affecting anything else with the battery itself.

I just had the new battery installed today. I’ll monitor the voltage level over the coming days and weeks to see whether the battery discharges at a slower rate than the old one, which was losing between 0.1 and 0.05V per day, when not being used. Below is a screenshot which I took this evening, for the past 15 days. It was at about 12.29V this morning, before I took it to the garage to have the new battery fitted.

I ended up getting a brand new battery fitted by my local independent garage. It was £170 including fitting, for a Varta EFB battery. They moved my BM2 battery monitor to my new battery. The new Varta battery even has a recess on the top which is the perfect size for the BM2 battery monitor! They also fitted the cable for my CTEK battery conditioner to the battery, so I can connect the CTEK device more easily, without having to mess around with crocodile clips.

I had another look at the CTEK instruction manual, and there’s a separate section with more info on the Recondition cycle. It says “Choose the Recond program to add the Recond step to the charging process. During the Recond step, voltage increases to create controlled gassing in the battery. Gassing mixes the battery acid and gives back energy to the battery”.

It sounds like most car batteries typically last 3-5 years, so I guess it’s not surprising that mine is starting to lose performance. Does anybody have any particular recommendations on best brand or type of battery for a Skoda Karoq? When I plugged my car reg into the Halfords website, it proposes either Halfords own brand, or a brand called Yuasa, which I’ve never heard of before. Both of them are EFB type. The Halfords own brand is £122.99, the Yuasa is £159, plus fitting cost of £27.00. I was expecting to see battery brands like Varta or Bosch.

I recharged the battery last weekend, using my CTEK charger. It has been in the garage all week apart from Tuesday, when my wife used it for a couple of short journeys of 10 minutes each, and a couple of 30-minute journeys. When I checked the BM2 app last night, it was showing the battery level having dropped from 12.62V (“OK”) last weekend to 12.26V (“low power”) this weekend. You can see the battery level progression in the attached screenshot. The battery voltage is dropping by around 0.03V to 0.05V per day. Does this kind of drop in battery performance over the course of a week mean that the battery definitely needs replacing, or is this typical of what a battery would normally lose per day? The “Cranking test” last night was showing “Low cranking voltage” of 9.27V. I have put it back on charge with my CTEK charger again today. I’m slightly confused by the comments about the “Recondition” cycle on the CTEK charger. Why would CTEK be recommending to do this once per year, if it’s bad for the battery? Is it really completely discharging the battery? According to the CTEK manual, this stage comes AFTER stage 6 ie. after the battery has been fully recharged. If it was completely discharging the battery, I would have thought it would do this BEFORE it recharges the battery, wouldn’t it? Please forgive my ignorance, if these are all dumb questions. I’ve never had to change a car battery before, so I have never paid any attention to this issue previously. I previously had a diesel BMW with stop-start functionality for more than 6 years, and I never had any problems with it, but most of my journeys in that car were more than 30 minutes each, and it was used almost every day. Our other previous car which was used mainly for short journeys (a Toyota Verso), which we kept for more than 6 years, also never gave us any problems with the 12V battery, but it didn’t have stop-start functionality, so maybe that’s the difference compared to our Skoda Karoq which replaced the Toyota Verso.

I just checked the CTEK user manual. Under the setting for “AGM” option, it doesn’t list any other types apart from AGM. So I’ll just stick with the standard / normal profile for car batteries. But I noticed that there is also an option for “Recondition” mode, which it says should be used after deep discharge, to maximise lifetime and capacity, with a suggestion that this should be done once per year. I have never used this program, in the 3 years since I bought this CTEK charger. I’ll give it a try next weekend, to see whether it makes any difference.

On my CTEK MXS 5.0 battery charger, there is a specific setting for recharging “AGM” batteries. But I have just been using the standard car battery setting. Should I be using the AGM setting for an EFB battery? I have no idea what these terms refer to!

It says EFB on the battery. It was almost completely discharged a couple of weeks ago, after using it only infrequently, and only for short trips. But I have recharged it since then with my CTEK MXS 5.0 battery charger/ conditioner. The Skoda breakdown assistance guy said that the almost complete discharge was likely to have reduced the future performance of the battery somewhat

I checked it this morning, and it’s now showing 12.62V. Is that the level where a 12V battery in reasonable condition should be?

I just unplugged the charger now. I noticed the voltage drop significantly, just after I unplugged it. It then started increasing again slowly. I’ll see what voltage it shows tomorrow morning. Without this BM2 device to see what’s happening to the voltage in real time, I would never have been able to see what actually happens when you use a battery charger