Possible new battery?

Timmo478 · Post by **Timmo478** » Tue Jul 16, 2019 7:01 pm

Hi guys I'll cut straight to it. Yesterday morning car turned over slow but started first time. In the afternoon when leaving work she turned over really slow then speeded up to normal and started first time. Checked battery with multimeter and its reading 12.8 ish volts engine off after a run. Whilst running alternator charging battery and we'll over 14V. This morning she read 12.48V before I started her and she strangely started fine. Also started fine after work today. Commute is only 3 miles each way (yes lazy but love driving her lol) and she didn't run all day Sunday. Battery doesn't look very old but also isn't a brand name by the looks of it. Battery seems to loose about 0.4V over night.
Cheers in advance hope everyone's well.

ph001 · Post by **ph001** » Tue Jul 16, 2019 9:58 pm

Those voltages sound ok to be honest but the voltage doesn’t always tell you the full story. My plan of attack would be to purchase a decent charger then leave it on the car overnight. If it still is very lazy to start in the morning then more likely to be starter motor. From what you have said i’d certainly be more swayed towards the starter but 3 mile commutes are certainly not good for battery longevity either.

buzyg · Post by **buzyg** » Tue Jul 16, 2019 10:17 pm

ph001 wrote: ↑Tue Jul 16, 2019 9:58 pm Those voltages sound ok to be honest but the voltage doesn’t always tell you the full story. My plan of attack would be to purchase a decent charger then leave it on the car overnight. If it still is very lazy to start in the morning then more likely to be starter motor. From what you have said i’d certainly be more swayed towards the starter but 3 mile commutes are certainly not good for battery longevity either.

What he said.

Mr Tidy · Post by **Mr Tidy** » Tue Jul 16, 2019 10:51 pm

I got my current Z4 in May 2016, and soon afterwards noticed it was a bit sluggish starting. Strangely it seemed to be worse when hot than cold, so my Indy thought it may be the starter motor.

Then in October I got an Amber EML which he diagnosed as post-cat sensors (both banks) and inlet Vanos solenoid in November 16.

So a new Vanos solenoid was fitted and the codes cleared.

December 16 another Amber EML, so I took it in again and the battery died during the diagnosis - which turned out to be for post-cat sensors again!

Anyway a new battery was fitted and the codes cleared once more and it's always started just fine since then.

Based on that experience, and what I have read on here, it seems a dying battery can throw up random fault codes. So if you do have any doubts about the condition of your battery it may not hurt to change it!

And why not go home the long way sometimes!

grumps · Post by **grumps** » Wed Jul 17, 2019 9:06 am

Mr Tidy wrote: ↑Tue Jul 16, 2019 10:51 pm And why not go home the long way sometimes!

...via Thurso!

Timmo478 · Post by **Timmo478** » Wed Jul 17, 2019 12:58 pm

Thanks guys appreciate the replies. Been going into work the fast way since Monday down the dual carriageway and cars been starting fine everytime. Even dropping the roof on the key and opening boot before I leave. I'm pretty sure it is battery after being left on the Sunday not driven. Will get it changed.

g3org3y · Post by **g3org3y** » Wed Jul 17, 2019 11:07 pm

Mr Tidy wrote: ↑Tue Jul 16, 2019 10:51 pm nyway a new battery was fitted and the codes cleared once more and it's always started just fine since then.

On the Z4 (unlike the later E90s), you don't need to code the battery to the car do you?

Mr Tidy · Post by **Mr Tidy** » Wed Jul 17, 2019 11:14 pm

g3org3y wrote: ↑Wed Jul 17, 2019 11:07 pm On the Z4 (unlike the later E90s), you don't need to code the battery to the car do you?

Thankfully you don't!

My 2006 plate E91 didn't need to be coded either - I think it's the later models with stop/start and AGM batteries that need coding.

My 57 plate E87 123d did need coding - battery plus coding cost over £250 at an Indy!

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