Battery not charging (but battery light not on)

[Qsilver7]

Originally Posted by mcfee03

Is the problem strange because the battery light _should_ be on if the battery is bad?

The above statement is a common misconception/misunderstanding of the BMW battery warning light.

The battery warning light illuminates when the battery is the VICTIM...not the culprit. The battery warning light illuminates when the alternator/charging system is not charging the battery...the alternator/charging system is the CULPRIT...the battery is the VICTIM.

[bcredliner]

How are you monitoring the alternator voltage?

When you were checking voltage with the engine run did you have a bunch of stuff that draws voltage on?

Have you verified the cables you removed are secured properly?

Many auto parts stores have the equipment to check the charging system without removing the battery or the alternator. While I have not used the free service I believe Autozone has that capability.

[mcfee03]

I'm monitoring voltage by connecting a volt meter to the battery directly (in the boot).

I checked the engine with load (headlights, air conditioning, revving the engine).

I dont know a store in Sydney (Aus) that test alternators.

Just very strange the battery light is NOT on. Is the "generator" the same as the altetnator? Is there a way for me to isolate and just test the alternator?

[andrewwynn]

No such thing as generator on modern cars they all use alternators. Mostly so they can easily maintain constant voltage with different RPM. You can monitor voltage from the accessory outlet (aka cigarette lighter socket). If the voltage stays near 13.8 at all rpm it's a bad battery.


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[bcredliner]

You can monitor voltage by unlocking the cluster and scrolling to test 9. You can check voltage at the alternator but reading at battery and under the hood should reflect what the alternator is putting out. You could check to see if there are any error codes. I would do more troubleshooting before purchasing an alternator.

Aren't there places that primarily sell batteries that have the capability of testing the charging system?

[mcfee03]

Originally Posted by bcredliner

You can monitor voltage by unlocking the cluster and scrolling to test 9.

I've not heard of this, some videos on youtube show me how. Doesn't this just tell me what a volt meter tells me anyway? Can an unlocked cluster tell me more specifically about the alternator itself?

I have an ODB tool (ELM327) and Torque Pro. Is that capable of telling me voltage?


There are no error codes relating to the alternator/electircal (just an O2 sensor and misfires I've had a while).

I called around, and I can't find any stores that test alternators

[bcredliner]

Only difference using the cluster is that you can monitor voltage when you are driving to see if it spikes or changes or just stays constant. Cluster monitors battery voltage which should range from about 13.2 to almost 14 volts if alternator is operating correctly.

I don't use either of the code readers you mention so don't know their capabilities.

[mcfee03]

So I tried getting to the alternator and broke/snapped something

It must have been brittle, as I didn't apply much force.

Is it safe to repair that crack? Is it the auxiliary water pump? Green fluid came out



http://i.imgur.com/htI55pG.jpg

[wpoll]

Looks like the aux. water pump. Good luck repairing it - it contains hot coolant so most glues won't work too well. You might be able to use JB-Weld.

Or this...

https://www.ecstuning.com/b-genuine-...p/64116913489/

[mcfee03]

Originally Posted by wpoll

Looks like the aux. water pump. Good luck repairing it

I'll try JB-Weld. Do I need a specific poxy (JB WELD 32507 ULTIMATE GREY GASKET MAKER & SEALANT - OIL RESIST, SENSOR SAFE 14g | eBay), or just the original one?

Is it okay to drive say 2km's with the auxiliary water pump broken?