dead as a ..

[norseman]

Hi guys

Parked my old ('98) BMW on the drive yesterday & found out this morning that I had inadvertently left the key in the ignition all night; good job we don't live in some of the UK's inner cities !

Went to start the car, totally dead.
Battery is a 3 year old Bosch 95ah (as opposed to the standard 70ah for my model) & was fully charged. Put my multi-meter on it this morning, only reading 5.96v
The ignition was turned completely off & nothing electrical left on or doors/boot partially open (should go to sleep after 16mins. anyway) Is it possible that simply leaving the key in the ignition could cause such a drain overnight? Owned the car for five years with no history of any power drain, even when unused for several days.

Battery now on charge with a Cetek, car is not needed for a couple of days so fingers crossed.
Any thoughts appreciated.

 

[jurassic sparkk]

Is it possible that simply leaving the key in the ignition could cause such a drain overnight?

In the off position not really no... Even if it did it would take longer to drain as you've got a high capacity battery.

Let it trickle and see if it charges back up. If it doesn't then time for a new battery my friend. I would check for any parasitic draws. A 95ah battery shouldn't die over night with such a minimal load.. so the alternator may be worth checking too...

 

[carmanmemoranda]

In the off position, but key inserted, some cars do not fully close down. Some cars will even "ping" to tell you the key is still in.

But charge the batttery and get it tested ideally.

 

[norseman]

In the off position not really no... Even if it did it would take longer to drain as you've got a high capacity battery.

Let it trickle and see if it charges back up. If it doesn't then time for a new battery my friend. I would check for any parasitic draws. A 95ah battery shouldn't die over night with such a minimal load.. so the alternator may be worth checking too...

Thanks for that. It's just that I'm not really a believer in coincidence

 

[norseman]

In the off position, but key inserted, some cars do not fully close down. Some cars will even "ping" to tell you the key is still in.

But charge the batttery and get it tested ideally.

Does 'ping' when boot open/lights left on etc. but at nearly 26 years old not quite as modern as that !
Will check the charge indicators on the Cetek after 24hrs. & if looking encouraging leave the car on charge for another 24h.
Last time I checked the alternator output it was 14.2v but I can check again when/if the car is up & running.

Appreciate your reply.

 

[Murdochcat]

How old is the battery ?

 

[norseman]

How old is the battery ?

28 months.
Car not used every day, but several times a week & battery trickle charged every couple of months.

 

[Stivino]

28 months

If it turns out to be kaput, it might still be in warranty.