Battery pancakes

[brucemillar]

Non Merc - But the same principal.

Folks. I just want to check my sanity - methodology and sanity please.

Just bought the wife a BMW X5 4.8is from a dealer (Yes I know I can take it back)

After the car had stood at our place for a few days. The battery was flat enough not, to want to start the car - clicking only, no cranking.

I put this down to me having been farting about cleaning the car. Charged up the battery and all was good.

Same thing happened again a few days later when I had been out messing about with the Radio and Sat Nav with the doors open. A quick (15 minute) charge and all was good again.

That time I also stuck an alternator tester on the battery. This showed that the alternator was/is pushing out 13.9VDC at tickover and the battery was looking good on a DVM 12.2 standing - 14.1 at tickover.

Last night - having had the car stood for 48 hours. I popped out the local garage. Turned the key at the house and the car fired up but it did sound slightly flat as it cranked. It fired so quickly I ignored it.

Drove 3 miles to filling station - filled up with petrol - turned the key to start - click, click, click.

I have a small USB cigarette lighter charging socket. That displayed 11.2VDC dropping to 9.2 when it tried to crank.

Wife came out in our trusty Pajero and we jump started first turn of the key.

So, after al of this I am thinking duff battery??

Why?

1) Car has no other problems
2) No aftermarket electrical kit fitted - all standard
3) No interior lights left on
4) Alternator and battery pass muster "after' the car is started! This says to me that the alternator is pushing a good steady voltage 13.9 when running. But the battery may simply not be holding that voltage when stood?

I will check the standing voltages today (when it stops raining). The car will have sat all night at this point. We could have a parasitic drain? But my thinking is that the way that this happens with a good alternator, my first port of cal should be a new 'known good' battery?

What say the panel?

 

[moonloops]

Check how old the battery is..

 

[grober]

Charging voltage seems a little low? Should be around 14.4 volts. According to the following there could be several causes. A dodgy alternator diode could cause poor charging and a parasitic load? If its a water cooled alternator[ BMW seem fond of these] could be expensive new but reconditined ones are fine from a vehicle electrical specialist.
ps Always check earth returns in these cases alternator to engine block[ if there is one]and engine block to chassis [ corrosion or partial breakage inside insulation]

Alternator & Charging System Checks (Alternator Testing)

 

[Ted]

That is a smidge low on the voltage, Bruce, but not enough to give you any issues I don't think.
I would certainly get the battery tested first and if it passes muster, start looking for a parasitic drain.
Shame - I was down in Kent last weekend with a Foxwell battery tester in the boot.

 

[brucemillar]

Thank you all for the replies. I did a Google on x5 Voltages for the 4.8is. 13.9 seems to be correct when running.

Anyway. I checked the battery this morning with no load and without having started the car from last night? It was down to 10.21 on my DVM across the terminals with the battery completely disconnected from the car. Way to low.

So I have it on charge (out of the car) will let it charge up > Disconnect from charger > Check voltage every 15 minutes or so > See if the battery holds a charge?

Google does say that the 4.8s is hard on batteries (most V8's are).

I did have a good look around the car for any obvious lights on etc? Nothing obvious to cause a drain.

If the battery holds charge (I guess I would prefer it not too) then I I could use my own mobile Ted here in Kent. Finding a drain on this thing will not be easy. It has more fuses than a fuse factory during special offer fuse week. These fuses are also perfectly positioned within the car to allow access to an upside down double jointed Ostrich. Which I am not.

 

[MikeInWimbledon]

What kind of battery charger are you using?

I'm no expert on these things, for sure, but a lot of people use old fashioned battery chargers, rather than these new all singing, all dancing' battery charger / conditioners.

If you're using an old charger, it might be worth investing £50 in one of these new fangled 21st century battery jobs. They do do a great job of reviving and sorting out older batteries. Classic and convertible car owners swear by them.

Better men than I can explain why - but here's a useful video:

https://www.youtube.com/watch?v=HB-yWujGSUw

 

[Cymruambyth]

I'm no expert on these things, for sure, but a lot of people use old fashioned battery chargers, rather than these new all singing, all dancing' battery charger / conditioners.

If you're using an old charger, it might be worth investing £50 in one of these new fangled 21st century battery jobs. They do do a great job of reviving and sorting out older batteries. Classic and convertible car owners swear by them.

Better men than I can explain why - but here's a useful video:

https://www.youtube.com/watch?v=HB-yWujGSUw

I`ve had this model for a few years now...great piece of kit.

 

[CabrioDave]

I'm with your thinking, Bruce: duff battery.

They can go to a state where they'll start the car OK (if car starts readily), but hold so little charge that they don't like having to run anything like interior lights for a while.

I had a Ford which never showed any symptoms, until I spent 20 minutes packing it for a holiday - with the doors and hatchback open, and therefore all (thirteen!) interior lights on. Almost totally flat.

New battery time!

 

[MikeInWimbledon]

That's answered the question

I`ve had this model for a few years now...great piece of kit.

If you've used that charger to recondition your existing battery and it hasn't worked, then it's time to buy a new battery.

 

[wu56Shoozz]

Don't think for a minute that because your battery looks like its holding a charge that its fine.. I own a Jeep with a Merc engine in it and its a grave danger to play with it like this.. for some reason it doesn't like an unhealthy battery and will throw a wobbly, from alarm going off to electric windows dropping of their own accord to CEL light lighting up, what's worse as it's even more temperamental on a jump start.. done wrongly and you risk blowing the ECU and TCM even both at the same time.. so be careful is what I'm saying, Start at the cheap end, look at the age of the battery, look at all your connections, make sure all the earths are good and clean the work up from there...

 

[Chrishazle]

Visit your local Halfords and ask for a battery and alternator test. I had to buy a new battery from Halfords Ashford (the main one near Outlet/B&Q) a year or so back (at very short notice on a Saturday morning), car had been on the conditioner for a few days but no green lights, used the big charger to start the car. Anyway, they had the battery I needed, charge me £10 to fit it, then ran an alternator test FOC!

 

[Cymruambyth]

If you've used that charger to recondition your existing battery and it hasn't worked, then it's time to buy a new battery.

I haven`t bought a new battery for any car for years

 

[brucemillar]

All

Thank you again for the helpful replies.

The battery was NOT on charge so that is not applicable here ;^) I have several chargers all of which are modern maintenance chargers that will and do cycle the battery.

When I got the 'old' battery out of the car (this is no easy task in an X5) I find that it has a viewing lens.

Green = Healthy
Black = Dodgy
Red = Duff

Mine was black!!

I bought a nice new Halfords branded battery with a 5 year warranty £130. So far so good!!

Fingers crossed.

 

[CabrioDave]

I haven`t bought a new battery for any car for years

Yes, it can be a bit of a lottery. My dad's MX5 was sold on at 13 years old ... absolutely fine with its original battery. The Ford mentioned above was 14 months old, at 18,000 miles. Go figure!

 

[Cymruambyth]

Yes, it can be a bit of a lottery. My dad's MX5 was sold on at 13 years old ... absolutely fine with its original battery. The Ford mentioned above was 14 months old, at 18,000 miles. Go figure!

I only stated that due to confusing post #9

 

[brucemillar]

Just found an interesting article on Google. On the X5, if the car fails to go to sleep correctly? Due to it detecting voltage drop(s), the gear selector will stay illuminated after the 16 minute, pre-sleep window.

My selector light is switching off, at the sixteen minutes, as are all other interior lights, after 2 minutes.

I left my illuminated USB volt reader in the cigarette lighter, so that I can take a crafty peak at the battery voltage, through the window, without waking the car up. It has stayed firmly on 12.3 since I installed the new battery at 14:00 today. I checked this against my DVM - 12.29vdc. So it is reasonably accurate.

I am hoping that we have fixed it and was a dying battery on it's last hurrah.

Tomorrow morning will tell.

 

[markjay]

Modern car batteries can last for many years. As long as they don't go into deep discharge. So now you've got a new battery just make sure you don't let it go flat and it will last for as long as you keep the car

 

[190]

I'd be concerned to measure only 12.3 volts. Assuming there is no real load on the battery that voltage indicates only 60% charge or even less if it's an AGM. I measure 12.7 volts on a fully charged standard battery.

 

[jaymanek]

Need a new battery for sure.

Also a "quick charge" is the worst thing you can do to a battery. Use a slow charger if you want to give the battery another go.

In my opinion, just fit a new battery!

 

[BaldGuy]

Buy an ML.....