[ArsE92]

Hi All

Pretty sure I know the answer to this one!

I went to start my car yesterday morning, and on pressing the Start button was met with deafening silence. No warnings on the dash or anything, just wouldn't crank.

I hooked it up to another car and it started straight away, so I went for a 20 minute run to try and get some charge in the battery. I made a few stops, and each time it started without issue although by the fourth stop the cranking was a bit 'lazy'.

I got it home, and put the battery on charge for four hours whilst I did some jobs around the house. Took the charger off, car wouldn't crank. Same again this morning. Hook it up with jump leads to my wife's car, starts first time.

The viewing window on the battery is 'black' which means it needs charging, but it definitely doesn't seem to be holding a charge. Also, there's a lot of greeny corrosion around the negative terminal. Is that 'normal'? The car is a 2007 335i E92.

So, how much should I expect to pay BMW for a battery including fitting? £120 ish?

[Reece]

Sorry to say but bmw wanted £380 for a battery + fitting and coding and mines an 08 320d your battery might be bigger

[M4rius]

Paid around £40 for z4 battery and swapped my self. Bought from ecp. Pretty sure they sell batteries for e9x for less than £100.

[ArsE92]

Originally Posted by Reece

Sorry to say but bmw wanted £380 for a battery + fitting and coding and mines an 08 320d your battery might be bigger

Sweet Mother of God.

Originally Posted by M4rius

Paid around £40 for z4 battery and swapped my self. Bought from ecp. Pretty sure they sell batteries for e9x for less than £100.

Did you code/register yourself?

[Reece]

But i paid £90 for mine fitted myself and didnt bother coding been on the car 16 months without a single problem and the battery had a 3 year warranty so if it does go il jus keep getting it swapped over

[ArsE92]

Originally Posted by Reece

But i paid £90 for mine fitted myself and didnt bother coding been on the car 16 months without a single problem and the battery had a 3 year warranty so if it does go il jus keep getting it swapped over

Ok, good call. I could always fit it and code it myself when I learn how to. I've got the cable and software just never had the time to learn.

Cheers

[tmarshall57]

My understanding is that if the replacement battery has the same amp hour capacity then it doesn't need coding/registering.

[M4rius]

I've never hear about battery needing coding until now, probably another myth made by dealers in order to make more money.

[John320d]

Batteries for diesels are larger because of the higher compression ratios.

[makkan00]

Disconnect the battery. Take the battery out and check all the wirings. Some forum members had the similar issues and wires were rusty/ naked and giving intermittent connection.
That corrosion does not look good. Clean it as good as you can.

You should also check the voltage on the battery with the multi-meter to see when its dead and after running for sometime and compare the difference.


Lastly, If you go for brand new battery, do not bother about coding and save the invoice.

The proper way is
1- If you change the battery to different capacity, you will have to change it in the main database of the car. And then step 3.
2- Same goes if you shift from standard battery (yours) to AGM battery (black in colour) and they are way better. But it has to be written in the car database, therefore car can adjust the values of charging / discharging. And then step 3.
3- If you change the battery with the same specs, you still need to reset the battery values, so car re-learn about the attributes of the new battery, charging and discharging timings (tmarshall57, answer to your question).

Good luck OP.

[kwano888]

Costco for Bosch batteries with 5 year warranty. Any problems and theres never a qualm and they will refund you.

[ArsE92]

Originally Posted by makkan00

Disconnect the battery. Take the battery out and check all the wirings. Some forum members had the similar issues and wires were rusty/ naked and giving intermittent connection.
That corrosion does not look good. Clean it as good as you can.

You should also check the voltage on the battery with the multi-meter to see when its dead and after running for sometime and compare the difference.


Lastly, If you go for brand new battery, do not bother about coding and save the invoice.

The proper way is
1- If you change the battery to different capacity, you will have to change it in the main database of the car. And then step 3.
2- Same goes if you shift from standard battery (yours) to AGM battery (black in colour) and they are way better. But it has to be written in the car database, therefore car can adjust the values of charging / discharging. And then step 3.
3- If you change the battery with the same specs, you still need to reset the battery values, so car re-learn about the attributes of the new battery, charging and discharging timings (tmarshall57, answer to your question).

Good luck OP.

Cheers Makkan. I'll disconnect and give you connections a good clean later on.

Failing that...

Originally Posted by kwano888

Costco for Bosch batteries with 5 year warranty. Any problems and theres never a qualm and they will refund you.

I'll do this...

Cheers all

[litany]

Originally Posted by M4rius

I've never hear about battery needing coding until now, probably another myth made by dealers in order to make more money.

It is not a myth

[KM79]

Originally Posted by litany

It is not a myth

Yip and you get 12 minutes to do it.... Huge cost

[ArsE92]

Hmm....

I got home tonight and cleaned up the negative terminal with a wire brush. Interestingly, as soon as I started fiddling with the negative terminal the car started clicking sporadically, which tells me that there was a dodgy connection?

After cleaning it I left it charging for a couple of hours, tried to start it, nothing doing.

So, I jump start it from the wife's car again and it starts first time, albeit a bit spluttery. Also, the fan is on full power. I take it for a spin to try and get some charge into the battery and the car is really hesitant.

I'm getting 12v (from the hidden menu on the dash) with the engine off and between 12.5v and 14v when driving.

I'm tired and stumped!

[makkan00]

Originally Posted by ArsE92

Hmm....

I got home tonight and cleaned up the negative terminal with a wire brush. Interestingly, as soon as I started fiddling with the negative terminal the car started clicking sporadically, which tells me that there was a dodgy connection?

After cleaning it I left it charging for a couple of hours, tried to start it, nothing doing.

So, I jump start it from the wife's car again and it starts first time, albeit a bit spluttery. Also, the fan is on full power. I take it for a spin to try and get some charge into the battery and the car is really hesitant.

I'm getting 12v (from the hidden menu on the dash) with the engine off and between 12.5v and 14v when driving.

I'm tired and stumped!

Hint: Concentrate on negative cable then!

You will have to take out the battery to check the health of all the cables.

[ArsE92]

Update - I've had the battery on charge all day. This morning it read 8V and then from about 11am it's been sat at 10V.

Seems to me like a dead cell?

Anyway, new battery has arrived from ECP so I'll be fitting that later.

[Frobius]

I'd say that if it's gone as low as 8v, it's fooked. I'd be more worried about what in the car caused that amount of drain.

[ArsE92]

Originally Posted by Frobius

I'd say that if it's gone as low as 8v, it's fooked. I'd be more worried about what in the car caused that amount of drain.

Yeah I'll have to keep my eye on it. I hope it's not the recently-fitted JB4.

I fitted a new battery yesterday and the car is fine now.