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Normal battery output?

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
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Kugaman1
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Normal battery output?

Post by Kugaman1 » Thu Nov 02, 2017 8:57 pm

Evening all.....

What should my battery be outputting without the engine running but the ignition at switch 2?

Did a scan today as Ive had a couple of little glitches that could be due to a dodgy battery.....

Mines showing 11.6v on a carly live scan.
It then goes to 12.8v when the engine is started.

Im thinking 11.6v is a bit low?

Time for a new battery before the weather gets much colder?

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Ducklakeview
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Normal battery output?

Post by Ducklakeview » Thu Nov 02, 2017 9:10 pm

Should be more than 12.8v with the engine running. About 13.8v on a fast idle is normal..

Mike

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ph001
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Normal battery output?

Post by ph001 » Thu Nov 02, 2017 9:30 pm

Remember the E89 has active battery management though so if it decides the battery doesn't need charging it might set the alternator voltage low. Saying that, if it really is 11.6 V (defo check with a multimeter first) then it should be charging at more than 12.8V to bring it back to full capacity. Confirm with a decent multimeter before going much further.
2007 E85 Z4 3.0Si manual :driving:
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2004 E46 M3 coupe manual - gone but not forgotten.

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Kugaman1
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Normal battery output?

Post by Kugaman1 » Thu Nov 02, 2017 9:32 pm

Will do.
Cheers all

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Smartbear
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Normal battery output?

Post by Smartbear » Thu Nov 02, 2017 9:32 pm

Mine sits at about 14.8v when driving :?
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e89 Sdrive 30i, this ones busted, pass me another...
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Kugaman1
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Normal battery output?

Post by Kugaman1 » Thu Nov 02, 2017 11:16 pm

Ok thanks, will try it on the way to the gym tomorrow.

See what the voltage is whilst driving.

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Kugaman1
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Normal battery output?

Post by Kugaman1 » Fri Nov 03, 2017 12:58 pm

Ok.
Put a meter on it this morning. With the car turned off, battery is showing 11.7v

Then Put Carly on and during a drive, battery went up to 13.4v

Question is, is my battery on the way out or will I be ok?

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Normal battery output?

Post by mcbutler » Fri Nov 03, 2017 1:17 pm

You cannot tell if the battery is failing from measuring the voltage.

You need to do a discharge test to measure the max amp output, most motor factors can do this for you, it takes around 20 seconds.
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Normal battery output?

Post by Gaffa22 » Fri Nov 03, 2017 1:56 pm

did you not get a warning light on the dash ?
I turned mine on yesterday and the battery warning came up, checked the voltage and it was 11.9v
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ph001
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Normal battery output?

Post by ph001 » Fri Nov 03, 2017 3:00 pm

Kugaman1 wrote: Fri Nov 03, 2017 12:58 pm Ok.
Put a meter on it this morning. With the car turned off, battery is showing 11.7v

Then Put Carly on and during a drive, battery went up to 13.4v

Question is, is my battery on the way out or will I be ok?
11.7V sounds a bit on the low side to me. If your battery is over 6 yrs old I would just replace it for new.
2007 E85 Z4 3.0Si manual :driving:
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2004 E46 M3 coupe manual - gone but not forgotten.

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Normal battery output?

Post by Poltergeist1966 » Fri Nov 03, 2017 3:43 pm

Just changed mine yesterday for a Varta AGM - the original battery was putting out 11.9v, and being charged at 14.8v.
Registered the new battery via Carly, and all is good.
2010 E89 30i M Sport 6sp manual in Melbourne Red.

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Normal battery output?

Post by Smartbear » Fri Nov 03, 2017 6:27 pm

Poltergeist1966 wrote: Fri Nov 03, 2017 3:43 pm Just changed mine yesterday for a Varta AGM - the original battery was putting out 11.9v, and being charged at 14.8v.
Registered the new battery via Carly, and all is good.
Is there a difference in the charging voltage of the new battery, what voltage is it when driving?
Rob
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e89 Sdrive 30i, this ones busted, pass me another...
e85 3.0si sold

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Kugaman1
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Normal battery output?

Post by Kugaman1 » Fri Nov 03, 2017 8:25 pm

ph001 wrote: Fri Nov 03, 2017 3:00 pm
11.7V sounds a bit on the low side to me. If your battery is over 6 yrs old I would just replace it for new.
Car is 4 years old.
However, no idea if it got a lot of stop/start use, so the battery may have had a hard time.....

Im going to give it a week or two and see how it goes....

Car seems to be performing fine today, so not sure if theres an issue or not....

Thanks for the feedback all.

Pbondar

Normal battery output?

Post by Pbondar » Sat Nov 04, 2017 11:50 am

Offload a freshly charged 12 v AGM battery should be sitting around 12.6v minimum. Even with some very minor current drain should sit above 12v

So whilst it’s true to say that only a capacity test will definitely show how much of an issue there is, a recently charged 12v battery completely off load that reads 11.6v is on its way out.

Having said that if the battery is still connected in a Z4 then it’s not truly off load as when you open the doors all sort of circuits fire up...

So the simple test I sent run the car for a few minutes, then stop, then disconnect a battery lead , wait 30 minutes measure voltage , if below 12 v fhen it’s going to the happy hunting ground of AGM batteries... :thumbsdown:

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ph001
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Normal battery output?

Post by ph001 » Sat Nov 04, 2017 2:30 pm

^^^good advice.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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