Does Battery Drain mean new battery?

[DW35]

Having only picked up the car from BMW after major suspension failure, less than a week in the next fault has reared its head.

After using the car on Monday (for an hour journey each way), the car was parked up for 3 days...come Friday, it's started on the buzzer and drove it to the shops 10 mins away...after an hour shopping, when I got back into the car I noticed the car asked me to set the clock again which was a little strange...car started first time and I made my way home...

I unloaded the car for about 20 mins and then when I was about to set off again, the electronics were pretty much dead and the car would not tick over...not a good start to the long weekend away we were about to set off on...

Got the AA out and they started the car and tested the battery...everything seemed fine so with the car running, it was suggested I run it for 45 mins which was ok since I was about to go a 3 hour drive...

It was suggested the initial flat battery was due to the car draining whilst unloading the car...having been parked up for 4 days completely untouched, I thought it would be ok having been in sleep mode...just as I was about to checkout of our lodge, same thing, the car did not have the power to start...this time accompanied with 4x4, DTC and ABS failure messages...another call to the AA who again get the car started for me to make my journey home and the failure messages cleared up within a couple of mins...

When I got home, I needed to start the car 2 times which seemed ok...just earlier, we popped out for dinner and again car starts ok...hour later after dinner, key in...clock reset again...car starts ok...

I've googled and found alot of E70 battery drain issues but it's hard to see one route cause...i'm betting my usual short journeys definitely isn't helping!

I hooked the car up to a trickle charger and it reads 14.2-14.4v when the cars on and 12.2-12.4v when off...this is normal right? Could this still mean the battery needs replacing?

I've read BMW now fit AGM (?) batteries as they are better and more reliable...also could I expect a main dealer program / fit a battery I bought elsewhere?

[X5Sport]

These cars draw serious power in standby (but next to nothing in 'sleep') with a current draw in 'radio ready' of 60A!!

AGM batteries are used because they are safer, and for no other reason.  No nasty corrosive liquids sloshing about eating holes in the bodywork!  They do not like being deep discharged, and are far less tolerant of abuse than the old 'wet' batteries.  The voltages you are seeing both on and off charge are fine - which is a good sign.  It may just need a full charge over 12 hours or so.

I would not be surprised if the Dealer had doors etc open and the car battery just went down.  They could have jumped it and then given it back without saying a word - wouldn't be the first dealer to pull that stunt!

Batteries on these cars are different as they are 'paired' to the car.  I don't know if this can be done other than with special kit.  I'm told this means the on board systems monitor the battery's ability to take and hold a charge.  Straight swaps are no longer as simple as they were (on say an E53).  Whether this also means you need a special battery too isn't clear.

Richard

[DW35]

Thanks for the info.

It could be as you said with the dealers as the car was at there for almost 2 weeks whilst the suspension was being sorted.

I'll charge it overnight tonight and see what that does as according to the charger I have, when the car is off, it shows a next to 0 amp draw...hopefully that is all that it is as there was signs of this previously.

Should be fun trying to get the car up kerb and onto the drive...this is when I wish I had a garage!

[DW35]

Came back to the car last night to find the battery had dropped to just under 10v.

Put it on charge overnight and this morning it read 11.7v...not sure if this is because I had the charger on the wrong setting though...needless the say the car wouldn't start so i chose the correct setting this time and will check on it tonight.

The car is booked in for diagnosis this Friday and I'm hoping it's just the battery since once again, Leeds Audi have said they will cover it 

[X5Sport]

Sounds like a cell has gone bad.  A connected and fully discharged battery will give approx 10.5V

A fully charged battery (needs checking 4 hours after last charge) should be around 12.2-12.6V

New battery probably required by the sounds of things.  How old is the car/current battery?  6 years is the approx lifespan of a well treated battery.  If it's been deep discharged (yours has) then that lifespan gets steadily shorter!!

Richard

[DW35]

Ok, makes sense...probably a bad cell so it no longer holds it's charge...

I think it's the original that came with the car so it's approaching 5 years now.

I just want to be able to start the car...i feel bad calling the AA out for the 3rd time just to give me a boost so I can start it...although I guess that's what the memberships for!

[Horizon]

Newer BMW's have "Inteligent Charging", it monitors the charge rate and when you change the battery you have to take it to the dealers and get them to re initialise the module, telling it what sort of battery is installed IE Gell or Silver etc.  If you dont have it reset they say it may over charge the battery and cook it.
Knowing BMW this is probably a scaremongering ploy to get you ask them to supply the battery and re set the module, but read up on it first before you make a decision

EDIT The AA will only attend a few times as per your small print in the  contract. If you do not sort out the problem they will refuse to turn out, only fair really as people would not service their cars, and rely on roadside assistance every day !

[DW35]

Yep I have heard the battery will need to be "paired" to the car...it's booked in at a local Sytner for tomorrow morning as the selling dealer (Sytner Audi) have said they will cover the cost on the battery...makes it easier as they invoice Audi direct

With regards to the AA, I called them last night, went through the scenario and they said its ok for me to call tomorrow morning to get someone out to give me a boost since the car does not start now.

[DW35]

Just a quick update.  Car went into BMW yesterday after the AA kindly gave a boost for the 3rd time!

A new battery fitted as the old one wasn't holding its charge.

Grateful to Leeds Audi who covered what would have been a £414 bill 

[graemeX5]

Sounds like a good result on the battery 

[X5Sport]

£414.  .  It had better be made of more than lead for that!  Good result anyway.

[Rusty]

[quote="X5Sport"]
£414.  .  It had better be made of more than lead for that!  Good result anyway.
[/quote]
Probably not, what with the price for scrap nowadays.

That is one heck of a price. Was that just for the battery or diagnostics and labour too?

Sent from my GT-I9000 using Tapatalk 2

[DW35]

Yep difnately a good result in the end.

£414 was broken down as £90 diagnosis and £324 to supply and fit the battery. I asked for a copy of the bill but they were not keen on giving me a copy with how much they charged Audi though...i have a feeling it was somewhat less!

[X5Sport]

Ouch!!  And yeah - probably 'mates rates' for in the trade!!

R