C30 battery drain

[MrB.]

I'm on my second C30 (fourth Volvo if you include my wife's previous 2 XC60s) and find them to be a great wee car. My first was a T5 that I had a few years back that I really liked, hence me buying another at the end of summer last year. This one is a 2009 2.0D R-Design SE with 100k on it.

Now I drive lots of other cars in my job, so the car does sit for periods of time not being used, and I was in the motor trade for nigh-on 30 years, so understand that cars don't like to sit around unused. A couple of months ago, my wife's Land Rover went flat, so I removed the battery, charged it, and all has been well since. Then it happened to the Volvo.

I managed to get it jump started, and I put it on charge overnight, yet the next day, nothing. I assumed that the battery (which I think would still have been the original) had had enough after 11 years and 100k miles, so I bought a new Bosch one and fitted it. Imagine my surprise that after a couple of days the car was flat again.

So, does anyone have a clue where to start? There is obviously a drain somewhere, but why now? The car has been fine for months, even when I haven't used it for days, even weeks, on end. And just to clarify, no lights left on, no other external sources of power fitted (such as Bluetooth, or anything aftermarket). I just find it odd that this has just started to happen all of a sudden.

Any help and advice appreciated.

[sherman]

Alternator would be my first guess. Its not charging the battery.
Its drained the battery to less than 12v and the car wont start with less than +12v

Starting the car takes alot of energy out of the battery and if nothing is charging it back up its going to go flat fast.

Edited by sherman on Wednesday 31st March 15:26

[MrB.]

sherman said:

Alternator would be my first guess. Its not charging the battery.
Its drained the battery to less than 12v and the car wont start with less than +12v

Starting the car takes alot of energy out of the battery and if nothing is charging it back up its going to go flat fast.

Edited by sherman on Wednesday 31st March 15:26

Even though I haven't driven it since fitting the new battery? In other words, I fitted it, started it, turned it off and then left it for a few days. So, in other words, I didn't go for a drive so surely if nothing is being used, the battery should still maintain its charge? Or am I being thick?

[Penelope Stopit]

MrB. said:

The car has been fine for months, even when I haven't used it for days, even weeks, on end

I just find it odd that this has just started to happen all of a sudden.

It's like that, it's just the way it is

All is good and then one day something starts going wrong

As long as there isn't a very high permanent drain on the battery (you'll know if it's a high current drain, when disconnecting and reconnecting the battery there shouldn't be any big sparks/arcing)

Use a multimeter that will measure up to 20 Amps, disconnect the battery negative lead, connect ammeter in series with the battery negative post and the negative battery lead and see what the current drain is

Make sure keys are out of the ignition and doors are locked, allow half an hour for all ECU's to shut down after connecting up the ammeter and arm any alarm that is normally armed - Then take a reading

[sherman]

If it only just had just 12v when newly fitted you could have drained it to just under 12v. You dont know how long the battery had sat before you got it. The car wont start with any less than 12v. The computer will just say no.

[MrB.]

Thanks for the replies. I needed some guidance of where to start looking, so this has been really helpful.

[MrB.]

It turns out this battery drain is coming from a fuse in the engine bay fuse box. It’s the one that controls the Climate Control element/additional heater (PTC). We’ve removed it and the car appears fine. Does anyone know what this does? Do I actually need this fuse?

Climate control system works fine, and all seems normal.