E91 Battery Replacement/Charging

[Jay_87]

Hello... Looking for a little advice, owned my 320d E91 for 3 years and its been a model of reliability but it would appear the battery is getting weak and is slow to start on these colder mornings, it showed signs of this last year but its toughed it out for another year

Is there anything I need to know before I go rushing into a job I was planning on doing myself... coding etc??

My other thoughts are I do a lot of short journeys - my commute too and from work is less than 5 miles and I stay pretty local at weekends. I have a battery conditioner that my track car is plugged into, I was thinking of sticking it on the BMW for a few nights and see if it has any effect but my question is.... do I charge from the battery or from the terminals under the bonnet?

Cheers!!

[d_a_n1979]

Jay_87 said:

Hello... Looking for a little advice, owned my 320d E91 for 3 years and its been a model of reliability but it would appear the battery is getting weak and is slow to start on these colder mornings, it showed signs of this last year but its toughed it out for another year

Is there anything I need to know before I go rushing into a job I was planning on doing myself... coding etc??

My other thoughts are I do a lot of short journeys - my commute too and from work is less than 5 miles and I stay pretty local at weekends. I have a battery conditioner that my track car is plugged into, I was thinking of sticking it on the BMW for a few nights and see if it has any effect but my question is.... do I charge from the battery or from the terminals under the bonnet?

Cheers!!

My pal has a E91 335i and he needed to have the battery coded in (IIRC) so it'll be the same for yours

Re the charger; I use a CTEK MXS 5.0:

https://www.amazon.co.uk/CTEK-MXS-5-0-Reconditions...

I've fixed the eyelet connections to the battery terminals and use it that way; I did the same with a previous E65 730D, zero issues

[Jay_87]

Thanks for the heads up ref coding, I'll see if I can get a friend to fit it that can do that at the same time.

Thats the same charger/conditioner I have, I'l get another set of ring terminals and give it a go for a week or so, might just need boosting up a touch.

[JakeT]

If it's a newer model, with stop start or iDrive then you will need to code it in. They also require an AGM battery.

As Dan has linked to, a CTek MXS5.0 will do the job fine. You just need to make sure that the IBS (Intelligent Battery Sensor) can 'see' that current. Using the underbonnet points means that the system will see it, and keep your battery in good health.

Tim Meek has a nice way of wiring one of these up in a six series on his YouTube channel.

https://www.youtube.com/watch?v=-agMG0nQ0Wo

[Jay_87]

Thanks for that,

Think im gonna give the battery charger a go for a few days and see if they sparks it back into good health, if not I'l get a new one fitted.

Thanks for the link to the video, will give that a watch later!

[d_a_n1979]

Jay_87 said:

Thanks for that,

Think im gonna give the battery charger a go for a few days and see if they sparks it back into good health, if not I'l get a new one fitted.

Thanks for the link to the video, will give that a watch later!

The CTEK charger will let you know if it's happy with your battery or not

Worth giving it ago before you buy a new battery.

See what Tanya batteries can do for you, stay away from ECP and the likes; their prices are a piss-take at the best of times

[Jay_87]

I went to ECP to start with... shocked was an understatement - Will check out Tanya!

It fired up nicely this morning but I'm going to connect the CTEK up to it this weekend and leave it for a while. Fingers cross that cures it

[d_a_n1979]

Jay_87 said:

I went to ECP to start with... shocked was an understatement - Will check out Tanya!

It fired up nicely this morning but I'm going to connect the CTEK up to it this weekend and leave it for a while. Fingers cross that cures it

Which battery do you need?

As daft as it sounds, Amazon have some good deals too. Personally I'd rather buy from a battery specialist, then at least if you've any issues you know you can deal with them directly

Edit: This this is the one you need: https://www.amazon.co.uk/Bosch-Car-Battery-Type-09...

Or is your car start/stop; so you need an AGM battery? I'm sure you can do without an AGM battery; I know my pals 335i doesn't have an AGM battery and he's never had any issues

[Jay_87]

Yeah its an 096 that I need, not stop/start so no need for the AGM battery as I understand it.

Looked on Tayna batteries are there prices are much better than ECP - £80 rather than £400!!

Just gotta speak to my autoelec friend and find out if they can code it for me if I do need to change.

Still hopeful my CTEK conditioner can save it!!

[d_a_n1979]

Jay_87 said:

Yeah its an 096 that I need, not stop/start so no need for the AGM battery as I understand it.

Looked on Tayna batteries are there prices are much better than ECP - £80 rather than £400!!

Just gotta speak to my autoelec friend and find out if they can code it for me if I do need to change.

Still hopeful my CTEK conditioner can save it!!

Ah perfect; I'd go for that Bosch @5 096 then, you'll not get better than that

If you're swapping battery like for like; I think the car just needs to be told it's a fresh battery. Think the coding only happens when it's a different battery spec, could be wrong...

The prices I saw on ECP were c£200 for the batteries, the AGM ones were £400 plus. But they've a discount code running currently too, still too bloody pricey.

You'd get it cheaper buying genuine via BMW!

[g3org3y]

d_a_n1979 said:

If you're swapping battery like for like; I think the car just needs to be told it's a fresh battery. Think the coding only happens when it's a different battery spec, could be wrong...

I have vague recollections that's the case.