[Rialas]

Can I pop into Halfords/eurocarparts and buy a battery of the shelf?
This is what I've normally done in the past choosing one of the top end bosch batteries but this is the first car I've owned where the battery needs to be coded.
A lot of guys mention agm batteries but I thought these were for start stop vehicles.

Either of these ?

http://www.eurocarparts.com/mobile/e...c080ccb&000020

http://www.eurocarparts.com/mobile/e...991dba7&000020

[Aragorn30d]

Check whats in your car and buy one the same. Or use the VIN decoder to find what was originally fitted if your worried someone might have changed it.

You'll probably find you can get the battery cheaper online:

https://www.tayna.co.uk/E44-Varta-Si...078-P7726.html

Varta and Bosch are the same product, and thats likely exactly the same battery as the Bosch you linked to, for signficantly less money.

[Digitalize]

No matter what you buy you'll need it coded.

[Rialas]

Originally Posted by Aragorn30d

Check whats in your car and buy one the same. Or use the VIN decoder to find what was originally fitted if your worried someone might have changed it.

You'll probably find you can get the battery cheaper online:

https://www.tayna.co.uk/E44-Varta-Si...078-P7726.html

Varta and Bosch are the same product, and thats likely exactly the same battery as the Bosch you linked to, for signficantly less money.

Thanks. Yes it seems to be the same rating as the bosh at 77ah.
Just checked mine, and it has an original bmw battery rated at 80ah. Just wondering if I should get a more powerful one.
Cheers.

[Rialas]

Originally Posted by Digitalize

No matter what you buy you'll need it coded.

Thanks, I may be able to code it with the carly app.
My biggest challenge is all those connections. Never seen so many on a battery before. And choosing a decent battery.

[Digitalize]

Carly can code it yes. There's no more connections than a normal battery, you remove the blocks from the terminals, it just looks more complicated and is a bit more of an arse to get in place.

You need to buy the battery add on for the app, think it's £8.

[ed330D]

First off, your battery is an AGM.

If you replace your battery with an identical specification AGM battery, all you need do is register it.

If you replace it with anything else you will have to recode it.

IMHO I would only replace using an identical specification battery.

[ed330D]

For a nice explanation of the why and wherefore read

http://www.e90post.com/forums/showthread.php?t=621420

[un1eash]

Hardest part is getting the old battery out, it's very heavy and a tight fit, trying to get the lower bracket bolt back in was fiddly too.

[Rialas]

Originally Posted by ed330D

First off, your battery is an AGM.

If you replace your battery with an identical specification AGM battery, all you need do is register it.

If you replace it with anything else you will have to recode it.

IMHO I would only replace using an identical specification battery.

Thanks. Aren't the original bmw agm batteries black? And the standard ones white (so I've read).

Btw. My car doesn't have stop start.

Tempted to just take it to bmw

Oops edit, mine is black. Agm it is then. Cheers.

[Rialas]

Originally Posted by Broken_Gearbox

Varta do some really good batteries. Duracell have now started producing them too. I'd only get a more powerful one if you have some after market audio add ons

Thanks,
Found this one which is the exact same spec, and I'll just register it.

https://www.tayna.co.uk/F21-Varta-St...080-P8720.html

Not even sure it needs a battery, but it's a bit sluggish turning over in the mornings.

Handy video.

[Digitalize]

Before buying a new battery, you can try just registering it as a new battery so the car is charging it differently and see if that helps, and plug it in to an external battery charger like a CTEK.

[un1eash]

Originally Posted by Digitalize

Before buying a new battery, you can try just registering it as a new battery so the car is charging it differently and see if that helps, and plug it in to an external battery charger like a CTEK.

Tired this with mine, would still die after 2 weeks. Since replacing been fine for a year now.

[Digitalize]

It's not a miracle fix, but if it's just slow cranking sometimes, it might help.

[Aragorn30d]

Mine slow cranks after a week of sitting. Its also failed to start twice, both times after i was cleaning or working on the car, and had doors and things open for an hour or two.

Clearly the battery is tired though, as an hour of interior lighting should be enough to flatten the massive battery that the diesels get.

Slightly annoying though, as the old Audi would shut the interior lighting off after 10mins, even if the door was left open. The BMW doesnt seem to do that.

[un1eash]

First signs my battery was dying was the clock resetting, would always start fine though. These cars can do some crazy things when the battery starts to die.