Another roof thread - Fixed

[obewan]

Like myself, a mate had an issue with the roof not opening/closing properly and a constant flashing red light.
A local garage stated it needed the sensors re-aligned and claimed 'fixed'
A week or so later the fault returned, next they said it needed a new command module

My mate took it to the local BMW dealer yesterday.
They checked it over. Fault - battery low
Charged up over night, roof working OK
£50 please

Battery is 9 years old. They said there was nothing wrong with it, no need to buy a new one , use the car more!
They added that the roof is considered 'none essential' so when the battery is low it's the first thing to 'shut down'

 

[Anonymous]

Like myself, a mate had an issue with the roof not opening/closing properly and a constant flashing red light.
A local garage stated it needed the sensors re-aligned and claimed 'fixed'
A week or so later the fault returned, next they said it needed a new command module

My mate took it to the local BMW dealer yesterday.
They checked it over. Fault - battery low
Charged up over night, roof working OK
£50 please

Battery is 9 years old. They said there was nothing wrong with it, no need to buy a new one , use the car more!
They added that the roof is considered 'none essential' so when the battery is low it's the first thing to 'shut down'

Although they are in part correct, a 9 year old battery on an E89 is on borrowed time, so a preventative swap out to a new AGM battery is highly recommended.. your age E89 suffers from the 'flat battery has just f$%ked up my electronic handbrake' syndrome..so there are more than one good reason to do this..IMHO..

 

[obewan]

Totally agree Pbondar
I've advised him of the potential issues (he's already had the 'car on lift warning') and is looking to get a new one
Tanya have an Enduroline for only £75

It's a bit frustrating really as at the outset I said it may be the battery and eliminate that first.
We put it on my motorbike smart charger but with hindsight (and looking at the manual :wink: ) it didn't have enough oomph to charge the battery - or we didn't leave long enough

I've since bought a Foxsur AGM smart charger and use it to top mine up every few weeks
Like me he is now trying to get his confidence back pressing the roof button

 

[Anonymous]

obewan, apologies, I must chastise myself for speed reading the post..I missed the fact that it was your friend not you...

Once those batteries are flat it can take a lot of effort to recharge them..my almost new Varta 80ah one was flat after 3 months of lockdown and my Lidl chargers wouldn't start the process of charging them..so I put an old fashioned 4 amp Ring charger on for about an hour to get it going then swapped over..took 26 hours to get back up to full charge!!

 

[obewan]

obewan, apologies, I must chastise myself for speed reading the post..I missed the fact that it was your friend not you...

Once those batteries are flat it can take a lot of effort to recharge them..my almost new Varta 80ah one was flat after 3 months of lockdown and my Lidl chargers wouldn't start the process of charging them..so I put an old fashioned 4 amp Ring charger on for about an hour to get it going then swapped over..took 26 hours to get back up to full charge!!

No worries
I know what you mean. When I first bought the Foxsur charger the battery was at 20%, it still wasn't showing fully charged after 24hrs.
I thought I'd bought a duff
Anyway a few hours later it did reach 100% and turn off.
Now when I put it on it only takes an hour or so if that

 

[mcbutler]

I always find these battery related posts odd. We all know that once a car is running it does not use any voltage from the battery at all, indeed the alternator is designed to operate all electrical systems simultaneously AND charge the battery at the same time, for obvious reasons.
I know that changing a battery does help because I did it on my 23i.
Are the E89's just hypersensetive, is the alternator inadequate!!!!!!!?????

 

[BRC]

If a battery is on borrowed time at 9 years then my original at 12 years hasn't heard the news. Nearly always hook it up to a Lidl charger if I know it might not be used for a week or two. E85 I should add and frankly I cannot sense any lack of perforamance from the battery which cranks as well as it did when I bought the car 8 years ago.

 

[Anonymous]

I always find these battery related posts odd. We all know that once a car is running it does not use any voltage from the battery at all, indeed the alternator is designed to operate all electrical systems simultaneously AND charge the battery at the same time, for obvious reasons.
I know that changing a battery does help because I did it on my 23i.
Are the E89's just hypersensetive, is the alternator inadequate!!!!!!!?????

Several points specifically on the E89...

It was one of the first / few to use regenerative braking...by its very concept to work it means that the battery cannot be fully charged otherwise the energy used by the alternator on braking would have nowhere to go..if you read the details it means that in normal operation the battery is only ever partly charged...also have massive surges of current an order of magnitude much more frequently than auto stop start Means the battery will get worn out sooner than if it had just the job of occasionally starting an engine..

It was an early adopter of the engine DME controlling the remote shut down of all other systems..running coolant pumps, sat nav, amps, usb, Bluetooth and importantly electronic rear handbrake..

So either the basic 180amp alternator or the uprated 210 amp alternator fitted to E89s with extra equipment is more than upto it..but it needs time to charge and frequent use to offset long periods of current drain by the E89 systems even when locked..

The three premature terminators of batteries on E89s are

Auto stop start
Incorrect / faulty battery sensor reset
Long periods of no use with attendant short journeys

TIS states 6 weeks max between battery recharges with battery connected or 3 months disconnected

It’s all logical Jim..

 

[Anonymous]

If a battery is on borrowed time at 9 years then my original at 12 years hasn't heard the news. Nearly always hook it up to a Lidl charger if I know it might not be used for a week or two. E85 I should add and frankly I cannot sense any lack of perforamance from the battery which cranks as well as it did when I bought the car 8 years ago.

See previous post

E85 is in the dark ages electrically speaking compared to the E89 which from that viewpoint has a dramatic improvement in battery life expectations if treated similarly..

 

[mcbutler]

I always find these battery related posts odd. We all know that once a car is running it does not use any voltage from the battery at all, indeed the alternator is designed to operate all electrical systems simultaneously AND charge the battery at the same time, for obvious reasons.
I know that changing a battery does help because I did it on my 23i.
Are the E89's just hypersensetive, is the alternator inadequate!!!!!!!?????

Several points specifically on the E89...

It was one of the first / few to use regenerative braking...by its very concept to work it means that the battery cannot be fully charged otherwise the energy used by the alternator on braking would have nowhere to go..if you read the details it means that in normal operation the battery is only ever partly charged...also have massive surges of current an order of magnitude much more frequently than auto stop start Means the battery will get worn out sooner than if it had just the job of occasionally starting an engine..

It was an early adopter of the engine DME controlling the remote shut down of all other systems..running coolant pumps, sat nav, amps, usb, Bluetooth and importantly electronic rear handbrake..

So either the basic 180amp alternator or the uprated 210 amp alternator fitted to E89s with extra equipment is more than upto it..but it needs time to charge and frequent use to offset long periods of current drain by the E89 systems even when locked..

The three premature terminators of batteries on E89s are

Auto stop start
Incorrect / faulty battery sensor reset
Long periods of no use with attendant short journeys

TIS states 6 weeks max between battery recharges with battery connected or 3 months disconnected

It’s all logical Jim..

As I understand it the cars alternator charges the battery to an 'optimum' level while the engine is running (pulling the car along) and regenerative braking (when slowing down) is used to top up the battery above optimum level if it has already been reached.

 

[tintoverano]

also, as the battery ages, it won't able to hold the voltage for the same amount of time as before, and you start getting the "increased battery consumption" warning in the mornings, regardless you done your mileage the other day with lots of breaking