Can a CTEK overcharge a battery?

T

TonyP

Active member
 Dorset
Just gone to start my Mk1 Golf which has been tucked up in the garage since I SORN'd it at the end of October, CTEK was showing all of the LED's lit, disconnected the CTEK, turned off the immobiliser, fuel pump just about ran but slowly & then nothing, no cranking, 10v on the battery etc.

The battery was new a couple of years ago, it may even be under warranty still - I need to check, but the battery appeared fine when I tucked the car up for the winter & the CTEK has been on ever since.

I thought CTEK's were meant to keep batteries in tip top condition?, however either my CTEK is now kaput or the battery is.

Has anyone experienced a CTEK actually killing a car battery rather than maintaining it, can it overcharge a battery over a period of time?, I thought as it was processor controlled it would protect against this.

I've already been to ECP once today, it took about 30 mins just to get served to collect my click & collect order of engine oil, I don't relish the thought of going back with the battery.
 
I have been using my Ctek for years and has always brought batteries back to life or kept them in full charge. Mind, the longest I have left it connected has been about 2 months, so not as long as yours.
 
Just been out to the garage having had the battery on an 20+ year old charger (the sort with an ammeter built into the front), after only 20 or so minutes the car cranked & briefly fired but it didn't quite catch long enough for it to keep going, hopefully a couple of hours on the old charger will see it get enough to start, battery is currently pulling 3 amps from the charger, odd that the CTEK hasn't kept it charged over the winter.
 
TonyP said:
Just been out to the garage having had the battery on an 20+ year old charger (the sort with an ammeter built into the front), after only 20 or so minutes the car cranked & briefly fired but it didn't quite catch long enough for it to keep going, hopefully a couple of hours on the old charger will see it get enough to start, battery is currently pulling 3 amps from the charger, odd that the CTEK hasn't kept it charged over the winter.
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That’s not normal behaviour, the ctek sounds faulty or the battery is goosed :o
Rob
 
I don't think the CTEKs continuously charge, they monitor the voltage and only kick in once it senses the charge dropping. Ive used their chargers for the past 10 years and on my second now, the first the selector buttons became dodgy. Always found them to be good chargers generally.

Tim.
 
TitanTim said:
I don't think the CTEKs continuously charge, they monitor the voltage and only kick in once it senses the charge dropping. Ive used their chargers for the past 10 years and on my second now, the first the selector buttons became dodgy. Always found them to be good chargers generally.

Tim.
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I get this, but, clearly something has gone wrong with my CTEK, that's my initial thought anyway, I guess I'll know after a couple of hours on my old charger, even if it had locked up in some way & works again I'm not sure I can trust it for any length of time.

The only thing I'm wondering is if I have a parasitic draw on the car that the CTEK can't keep up with, but I wouldn't have expected it to reach the 7 'pulse' stage as per below from the instructions below.

"STEP 7 PULSE Maintaining the battery at 95–100% capacity. The charger monitors the battery voltage and gives a pulse when necessary to keep the battery fully charged"

It looks like CTEK offer a 5 year warranty, if I can find the receipt that it :x
 
A couple of years ago my previous model ctek went bad and discharged my battery completely over the winter sorn, but the battery re-charged fine and is still going strong. I've got a new ctek and all is fine. The battery is, unbelievably, the 2003 original! So hopefully yours will be OK.

I think the old ctek only had two years warranty, many of the later ones are 5 years now so worth checking your paperwork :thumbsup:
 
I've used an Airflow Battery Conditioner for years without any problems. I quite like the ability to get a battery charge indication when you disconnect from the mains.

http://www.airflow-uk.co.uk/Battery-Conditioner.html
 
I'm not sure what to make of this now, I charged the battery for only 90 mins or so on the old charger, as expected it wasn't long enough & provided only a few cranks before going flat again, I then hooked up the CTEK & left it again for a couple of days after which the battery had plenty of charge, car was a bit reluctant to start after a few months idle & so I would have taken quite a bit out of the battery, nevertheless it held up fine & must have had a decent charge.

To me it seems like both the battery & CTEK are ok & that somehow the CTEK had locked up having been charging for months, maybe I should just switch it off for a day or two once in a while.
 
Believe me, if your battery has been sat at 10V for any period of time more then a few days, the plates will be severely sulphated. This results in a large decrease in capacity and high impedance. Time for a new battery me thinks.
 
I have had different CTEKS causing issues on batteries, even on the M (which still has the same battery), on the service the dealer told me that they had to charge the battery even though I had it on the CTEK for the months before that time.

The Porsche battery had been on a CTEK as well and that died completely, but can not for sure attribute that to the CTEK though.

The Golf however has been on a CTEK for 10 years and that is still going fine.
 
TonyP said:
I'm not sure what to make of this now, I charged the battery for only 90 mins or so on the old charger, as expected it wasn't long enough & provided only a few cranks before going flat again, I then hooked up the CTEK & left it again for a couple of days after which the battery had plenty of charge, car was a bit reluctant to start after a few months idle & so I would have taken quite a bit out of the battery, nevertheless it held up fine & must have had a decent charge.

To me it seems like both the battery & CTEK are ok & that somehow the CTEK had locked up having been charging for months, maybe I should just switch it off for a day or two once in a while.
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I am not sure if it is just me but I try to remove mine from charge every now and then to avoid any chance of over charging. I have 2 Cteks (3.8) that I swap between 3 cars generally but at certain points we have had 5 vehicles that were all needing a charge at some point. Especially in the cold weather and when I lost my licence recently.

Our original Ctek died a couple of weeks ago after 7 years. It was charging ok but the mode button became a little temperamental.

I haven't heard of any issues with Cteks frying batteries but it is something I am a little paranoid about when I lock the garage on think my pride and joys could end up being barbecued.

H.
 
I have that mode button problem on one of mine as well, once I hook it up it is like a game of trying to press the button the right number of times as only one out of every 5 clicks actually works :lol:
 
Mine got to a point where it wouldn't move after 10 presses and the would jump 3 places. Nothing for another 10 presses and then the same again.

The good thing about the new model is that it stays in the same mode when you unplug it from the car and stays on standby. The old ones went barmy if you unplugged the car and left the power on.

H.
 
At least the later models don’t have that button and remember your last setting.
 
I’ve got a 12v golf cart maintenance charger. It cycles the battery between 12.7 and 13.5v - it has no bells or whistles, lights or mode selection - just connect to the under bonnet pins and forget it - It only cost me £8 from Makro years ago.

The zed hibernated in Nov 2017 and when I checked the other day the reading across the pins was 13.2v
 
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