Can I change the battery in a Mini Cooper 2009
Discussion
Morning All
This is the first time I have posted on a site like this so I hope I have put my query under the correct forum.
I own a UK registered 2009 Mini Cooper - it is the model with the stop/start technology. The car battery is nearing the end of it's life and I need to replace it. I will be buying a like for like battery so won't be taking an short cuts with a cheaper battery.
I have spoken directly with BMW and the cost to supply and fit a battery for me is just over £320. I have been told that I won't be able to fit a battery myself as the car will need reprogramming once the new battery is in situ.
I am capable of swapping a car battery over but I am concerned that I may end up with a non working car as I don't have the knowledge to re programme.
Is there anyone out there who can advise on whether it is possible to just swap batteries over on a 2009 Mini with stop/start technology without causing major technical problems or am I being spun a yarn by the garage?
Thanks for taking the time to read my post. Any advice would be much appreciated
This is the first time I have posted on a site like this so I hope I have put my query under the correct forum.
I own a UK registered 2009 Mini Cooper - it is the model with the stop/start technology. The car battery is nearing the end of it's life and I need to replace it. I will be buying a like for like battery so won't be taking an short cuts with a cheaper battery.
I have spoken directly with BMW and the cost to supply and fit a battery for me is just over £320. I have been told that I won't be able to fit a battery myself as the car will need reprogramming once the new battery is in situ.
I am capable of swapping a car battery over but I am concerned that I may end up with a non working car as I don't have the knowledge to re programme.
Is there anyone out there who can advise on whether it is possible to just swap batteries over on a 2009 Mini with stop/start technology without causing major technical problems or am I being spun a yarn by the garage?
Thanks for taking the time to read my post. Any advice would be much appreciated
£320 is a bit much isn't it!
Most stop/start systems require a reset using diagnostic equipment when replacing the battery, some will self adapt, not sure on the Mini though. You are more likely to suffer other electrical gremlins first though. You can get memory savers that plug into the diagnostic port that keeps the system alive while the battery is disconnected, this helps keep radio codes and ecu adaptation values from being erased, but it wont reset the stop/start system.
Most stop/start systems require a reset using diagnostic equipment when replacing the battery, some will self adapt, not sure on the Mini though. You are more likely to suffer other electrical gremlins first though. You can get memory savers that plug into the diagnostic port that keeps the system alive while the battery is disconnected, this helps keep radio codes and ecu adaptation values from being erased, but it wont reset the stop/start system.
Does that mean you can neither disconnect the battery or fit a cut out switch? My wife fancies a cooper, but she has 3cars so one may sand a month without moving, she can disconnect the battery when she leaves it, but if she had a cooper then this says you can't disconnect,so battery goes flag and then 300 pounds to replace/re programme. Is that right?
Thanks for all your replies to date
The £320 is to supply and fit the battery. I know BMW are a bit pricey but even they don't have the cheek to charge that much for a battery alone.
I shall wait and see if I get any further replies but from what you are saying it appears I am going to have to pay the price to get it reset. Ouch.
To BERW - i guess if battery just goes flat because the car has not been used for a couple of months, and the battery can be recharged then the garage would just be charging the cost of reprogramming.
In my case I know the battery is getting to the end of its useful life and I don't want to wait until car completely breaks down before replacing it.
It is all well and good having a nice motor but no so good when it needs basic maintenance as it seems most has to be done by BMW.
The £320 is to supply and fit the battery. I know BMW are a bit pricey but even they don't have the cheek to charge that much for a battery alone.
I shall wait and see if I get any further replies but from what you are saying it appears I am going to have to pay the price to get it reset. Ouch.
To BERW - i guess if battery just goes flat because the car has not been used for a couple of months, and the battery can be recharged then the garage would just be charging the cost of reprogramming.
In my case I know the battery is getting to the end of its useful life and I don't want to wait until car completely breaks down before replacing it.
It is all well and good having a nice motor but no so good when it needs basic maintenance as it seems most has to be done by BMW.
How do you know its coming to the end of its useful life? Are you just changing it because it's four years old and winter is coming? I've had batteries last much longer (the one in the TVR is ten years old). Have you had it tested (local motor factors will do this for free). Find your local independent BMW dealer and ask them as well. ''If it aint broke dont fix it'' 
Edited by SwanJack on Friday 13th September 13:54
I have not had it tested.
Thanks for the tip re free testing. I will get that done
Battery has been in there from new and I was told by BMW the battery lifespan is about 4 years. I have had a few intermittent electrical problems warning lights flash off and on and the boot occasionally opens as I am driving along.
I had a look on google and saw other people experiencing similar problems that were resolved by replacing the battery so I thought before paying BMW to do lots of expensive electrical diagnostics I'd take the common sense approach and replace the battery (when I had that brain wave I obviously thought it would be straightforward to just swap batteries over).
Thanks for the tip re free testing. I will get that done
Battery has been in there from new and I was told by BMW the battery lifespan is about 4 years. I have had a few intermittent electrical problems warning lights flash off and on and the boot occasionally opens as I am driving along.
I had a look on google and saw other people experiencing similar problems that were resolved by replacing the battery so I thought before paying BMW to do lots of expensive electrical diagnostics I'd take the common sense approach and replace the battery (when I had that brain wave I obviously thought it would be straightforward to just swap batteries over).
Cars fitted with stop/start systems do put a strain on batteries. Its not like our normal cars when the car is started and the battery recovers quickly and stays running to the end of the journey. Constantly starting the car even after a mile can shorten the battery life quite a bit.
The reset is required to recalibrate the voltage and capacity of the new battery as the system constantly monitors the voltage and re adapts as the battery gets older.
As the battery gets tired the system allows it to charge more before allowing the stop start to resume. Also if the battery gets low during a stop period it will halt stop start and restart the engine until the battery has recovered.
Its all a load of ecomentallist rubbish though, what you save in fuel you probably pay back in batteries, and what we save on the environment we put back in when recycling said dead batteries.
Next time just buy a normal car
The reset is required to recalibrate the voltage and capacity of the new battery as the system constantly monitors the voltage and re adapts as the battery gets older.
As the battery gets tired the system allows it to charge more before allowing the stop start to resume. Also if the battery gets low during a stop period it will halt stop start and restart the engine until the battery has recovered.
Its all a load of ecomentallist rubbish though, what you save in fuel you probably pay back in batteries, and what we save on the environment we put back in when recycling said dead batteries.
Next time just buy a normal car
Just curious..... if you called out someone like RAC battery service would they have some means of keeping the car "live" while replacing the battery?
Well they should do, plenty of tools on the market now for such a purpose and being a professional battery replacement service I would expect them to have one.
Its not about just saving the radio code though, the car has to know it is fitted with a new battery.
You could just buy a new battery from Halfords or A.N.Other battery supplier to the right spec then get a local diagnostic expert to reset the system. Probably cost half the price of BMW.
Its not about just saving the radio code though, the car has to know it is fitted with a new battery.
You could just buy a new battery from Halfords or A.N.Other battery supplier to the right spec then get a local diagnostic expert to reset the system. Probably cost half the price of BMW.
I've read Mikey G's post about the reasons why the car needs a re-set after fitting a new battery and everybody seems to accept that this is the case. However I still find it hard to understand. Surely it's just a matter of the system detecting when the battery is getting too low to start the engine and bye-passing the stop/start?
I can understand the need for a re-set if the car has regenerative braking. If you removed an old battery with low charge and fitted a new fully charged battery, it would not do for the car to try pumping a load of recovered brake energy into the full battery. Serious damage could be caused.
Sorry to side-track the main topic. I must confess that I was always a bit weak on electrics so I'm probably wrong.
I can understand the need for a re-set if the car has regenerative braking. If you removed an old battery with low charge and fitted a new fully charged battery, it would not do for the car to try pumping a load of recovered brake energy into the full battery. Serious damage could be caused.
Sorry to side-track the main topic. I must confess that I was always a bit weak on electrics so I'm probably wrong.
The BMW system does use a method of regenerative braking. The alternator doesn't activate all the time and is mostly used when the engine is slowing down. This means the engine is using less fuel to recharge the battery and makes use of the free energy deceleration gives it.
Normal lead acid batteries are meant to remain fully charged only being used for starting the car so they are designed for that one burst of use less often, they don't like being drained for long periods of time.
Batteries in stop start cars are similar in design to a leisure battery, i.e. designed to be drained to a lower voltage more times. As like any battery it loses its efficiency over time, the more it drains and recharges it loses a little bit of power/capacity every cycle, a battery has a maximum number of cycles.
The stop start system needs to compensate for this for it to work effectively, it will notice the nominal voltage of the battery will drop over time so it tells the alternator to work that little bit harder. It may not be much over a few days use but over the life of the battery could become significant.
Normal lead acid batteries are meant to remain fully charged only being used for starting the car so they are designed for that one burst of use less often, they don't like being drained for long periods of time.
Batteries in stop start cars are similar in design to a leisure battery, i.e. designed to be drained to a lower voltage more times. As like any battery it loses its efficiency over time, the more it drains and recharges it loses a little bit of power/capacity every cycle, a battery has a maximum number of cycles.
The stop start system needs to compensate for this for it to work effectively, it will notice the nominal voltage of the battery will drop over time so it tells the alternator to work that little bit harder. It may not be much over a few days use but over the life of the battery could become significant.
MsMini said:
I have not had it tested.
Thanks for the tip re free testing. I will get that done
Battery has been in there from new and I was told by BMW the battery lifespan is about 4 years. I have had a few intermittent electrical problems warning lights flash off and on and the boot occasionally opens as I am driving along.
I had a look on google and saw other people experiencing similar problems that were resolved by replacing the battery so I thought before paying BMW to do lots of expensive electrical diagnostics I'd take the common sense approach and replace the battery (when I had that brain wave I obviously thought it would be straightforward to just swap batteries over).
Of course mini will say the life span is 4 years.... They get to charge you that silly amount to change it Thanks for the tip re free testing. I will get that done
Battery has been in there from new and I was told by BMW the battery lifespan is about 4 years. I have had a few intermittent electrical problems warning lights flash off and on and the boot occasionally opens as I am driving along.
I had a look on google and saw other people experiencing similar problems that were resolved by replacing the battery so I thought before paying BMW to do lots of expensive electrical diagnostics I'd take the common sense approach and replace the battery (when I had that brain wave I obviously thought it would be straightforward to just swap batteries over).
Mikey G said:
The BMW system does use a method of regenerative braking. The alternator doesn't activate all the time and is mostly used when the engine is slowing down...
I think what you're talking about there is "intelligent charging" or some similar term, but not regenerative braking. It does some tricks to get the most efficient charge for the battery. As you say it increases the charge rate as the car is slowing and it also increases the voltage when the battery is cold, up to 18v I believe.Gassing Station | New MINIs | Top of Page | What's New | My Stuff