Battery

[BeardyJon]

I really need to get to the bottom of a bit of an annoyance with the battery of my 20i. It's mostly fine, but there are a couple issues that crop up every now and then.

The auto start/stop rarely, if ever, works. I've read a lot about how it should work and its subject to a lot of variables, however all being aligned, it still sometimes doesn't work. I've determined its likely that the battery isn't holding enough charge to do the stop/start properly, as if I do a 300 mile journey, it will work fine. Which also tells me the alternator is working (although how efficiently, I don't know).

The other thing is that sometimes the car doesn't start up easily. The starter motor will turn over quite slowly as if the battery is flat. Especially if it's been standing for a couple of days.

I've had the battery tested a few times all with different results:

• I've diagnosed it with Carly, and that says its fine.

• I bought a voltage meter (one that sticks in your cigarette lighter) and the voltage looks fine.

• One Halfords said that it was probably at 70-75% capacity/health and would likely need replacing soon.

• Another Halfords said the battery is good and that there's a "system noise issue" (what does that even mean?). He pointed at some switches to the side of the battery and said they might be causing the problem.

It's an original Exide battery (70AH) from factory on a 2012 car, so might be due to be changed anyway, but before I replace it (with an 80/90AH battery) I just thought I'd throw this out there to see if anyone here might have any idea? or a way to definitively test whether the battery is good or not.

 

[Gwest44]

Where are you based - I have an unused battery for sale on the forum following the departure of my E89 the other month?

 

[Jembo]

A few points I’ve noticed:
- Start stop is typically disabled during the first few minutes of driving - the more inclement the weather gets, the longer it will take to kick in
- Our Volvo tells us when S/S is & is not available, Typically after SWIMBO goes shopping or visiting family locally, it hibernates for a while when I drive it
- a CTek 5.0 has a recon function that seems to restore more power for longer, might be worth investing in one or asking a friend to borrow

 

[enuff_zed]

Not sure, but I think it was Smartbear who discovered you can code the Start Stop to off.
If you're thinking of keeping the car for a long time, consider all the extra, unnecessary wear on the starter for one thing.
Personally I find it an annoying function, put there merely to shut up the greenies and to help it pass the initial model type emissions tests.
Not got round to coding, but switching it off is one of my cockpit checks every time I get in.

However, in your case I think it is pointing to the battery not being in the best of health and would look to replace it.

 

[Smartbear]

Hi, when you say the voltage looks fine what reading do you get after the cars sat for a couple of days?
Rob

 

[BeardyJon]

Hi, when you say the voltage looks fine what reading do you get after the cars sat for a couple of days?
Rob

Not too sure, I'll have to check that next time the car is left for a few days. I can't remember if it had been standing for a few days last time I checked the battery.

Curious about what the Halfords guy said about system noise though. What doest that even mean? He showed me the digital meter he used to test it and pointed towards some numbers that said there was noise. But what is that?

 

[enuff_zed]

Hi, when you say the voltage looks fine what reading do you get after the cars sat for a couple of days?
Rob

Not too sure, I'll have to check that next time the car is left for a few days. I can't remember if it had been standing for a few days last time I checked the battery.

Curious about what the Halfords guy said about system noise though. What doest that even mean? He showed me the digital meter he used to test it and pointed towards some numbers that said there was noise. But what is that?

My guess would be that even when you think the car is switched off, there is something still drawing power.
I have noticed with mine that once I park it in the garage and lock it, there are still clunks and whirrs happening for quite a while as it gradually nods off. So I wonder whether the Halfords gadget was seeing all that stuff going on, or whether you do have some kind of parasitic drain?

 

[Ole gits rule]

Did you say the battery was the original one, will the roof open off the key without the engine running, if it won't open then IMHO the battery needs to be changed

My car can sit for several weeks with no issues starting the car although it does not like opening /closing the roof off the key untilI have driven a fair few miles.

S/S is a pain anyway, SWMBO has it. on her DS and it very rarely works and has been that was since the day we picked it up brand new.

 

[Mr Tidy]

Not directly related but the only car I had with Stop/Start was a 2007 123d.

The AGM battery didn't quite make it to 55,000 miles or 5 years, so once the new one was fitted I turned Stop/Start off every time before I drove away! But despite that the starter motor died at 77,000 miles and 6 and a half years.

If I ever buy another car fitted with it I'll be turning it off!

 

[BeardyJon]

Where are you based - I have an unused battery for sale on the forum following the departure of my E89 the other month?

Thanks, but I'm looking to get a higher amp rating battery than the current one, so it's not for me.

 

[BeardyJon]

Did you say the battery was the original one, will the roof open off the key without the engine running, if it won't open then IMHO the battery needs to be changed

My car can sit for several weeks with no issues starting the car although it does not like opening /closing the roof off the key untilI have driven a fair few miles.

S/S is a pain anyway, SWMBO has it. on her DS and it very rarely works and has been that was since the day we picked it up brand new.

Sometimes the roof will unlatch and then refuse to open further with the engine off, and that's when I notice the battery being low. So yeah, you're probably right and the battery could do with a change. That's probably all it is. But the system noise thing really confused me.

My guess would be that even when you think the car is switched off, there is something still drawing power.
I have noticed with mine that once I park it in the garage and lock it, there are still clunks and whirrs happening for quite a while as it gradually nods off. So I wonder whether the Halfords gadget was seeing all that stuff going on, or whether you do have some kind of parasitic drain?

Yeah my car does the same and I've heard whirrs and clunks after the car is switched off too so maybe you're right.

Regarding upgrading the battery to an 80ah/90ah one instead of a 70ah one, does anyone have any recommendations? I wanna make sure I buy the right size and battery sizes all seem to be different and there doesn't seem to be a standard?

 

[enuff_zed]

Regarding upgrading the battery to an 80ah/90ah one instead of a 70ah one, does anyone have any recommendations? I wanna make sure I buy the right size and battery sizes all seem to be different and there doesn't seem to be a standard?

Not changed one on my E89 yet, but I'm pretty sure I've read that if you change like for like then you can use a simple reader to register it, but if you change the battery size then you need to code it to the car so it knows it's got a different ah one in it. Must be something to do with how it monitors and charges it.

 

[BeardyJon]

Yeah the coding is fine as I've got Carly so can do all that. Just wanna make sure the battery I buy will actually fit in the car properly.

 

[enuff_zed]

Yeah the coding is fine as I've got Carly so can do all that.

I'll be back in my box if you need me.

 

[BeardyJon]

Yeah the coding is fine as I've got Carly so can do all that.

I'll be back in my box if you need me.

Haha! I just know the "do you need to code your battery change" debate has raged for a long time on the forum so thought I'd make it clear before it sets off again