Battery or CTEK charger issue?

[JamesK]

Just want to check what "normal" behaviour is for my CTEK 3600:

http://www.ctekchargers.co.uk/ctek-xs3600.php

The battery is either knackered or the charger is. Battery goes flat in about a week which isn't great. When I put the charger on it tops up the battery to start the car quite quickly but the charger gets quite hot. In theory if I leave it connected it will revert to pulsing once the battery is fully charged.

How long should I expect that to take? I've left it on most of a day, it doesn't get to that full stage and the charger is worryingly hot by then so I always lose my nerve and turn it off.

The battery is relatively new according to the docs (2 years or less) but the car didn't get used that often - would that reduce it's capacity sufficiently to stop it fully charging as well as retaining the charge?

[griffdude]

Deleted double post

[griffdude]

Hi James
My Griff flattens it's battery in about 10-14 days if left unplugged & undriven. Like you I have one of these CTek thingies & the Griff lives on it permenantly. Since using the CTek, the battery has caused no problems & the Griff always starts at the first attempt.

[BrianMillar]

The charge time can be calculated given the Ah capacity of the battery and the output of the charger

For example.

Estimating your battery is 75Ah capacity,
Given the CTEK max charge rate is 3.6A
Then time to fully charge battery is approx 25h

So maybe you are taking the battery off charge a bit too soon.

The CTEK is not really designed to charge batteries from flat it is just really to top them up and hold them fully charged so I am not surprised it is getting a bit hot.

[JamesK]

Thanks for that Brian. Interesting theory that I should leave it on longer to cool it down! I'll try and top it up over the long weekend in 6 hourish bursts and see if anything changes...

[alexcurtis]

Hi i have a ctek on the westie and it lives on it all the time ( 7 years) never noticed how hot it gets though it is quite compact compared to an accumate which the griff lives but as said they are designed not to charge the battery from flat, though i am sure they will have a thermal cut out on them to avoid any fire risk...

[ESDavey]

Like the guys above, I keep my CTEK connected when the Griff is in the garage. It gets hot so I prop it at an angle in the footwell to get max air around it. I suggest you keep it on all the time.

I have recently replaced my battery (Halfords £90 4yr warranty), the previous battery lasted 6 years which I think is normal service life.

[pxw]

Don't have your charger hard wired to the car, it has a discharge element to it's cycle so it'll flatten your battery if it's not plugged in the wall
I've taken mine out of the car for this reason