2003 4.4i with ABS lights on plus battery

[Stevo96]

Thanks guys, really appreciate the feedback. The battery is now on charge overnight, I shall report back tomorrow with the voltage readings. I'll be peed off if the battery is at fault given the PO said he had it checked by 3 different mecahnics... he never mentioned having the alternator checked so that will be the next thing to check after the battery.

[bcredliner]

You can check the battery voltage and the alternator output by unlocking the cluster and going to test 9. Don't know about Australia but most auto parts stores here will load test the battery for free.

[Skyline]

Originally Posted by Stevo96

Thanks guys, really appreciate the feedback. The battery is now on charge overnight, I shall report back tomorrow with the voltage readings. I'll be peed off if the battery is at fault given the PO said he had it checked by 3 different mecahnics... he never mentioned having the alternator checked so that will be the next thing to check after the battery.

It's also possible the PO used the wrong battery. These cars use a lot of juice, and need the proper, and quite large, and costly, battery. Not a place to cut corners. I do concur with trader4's comments as well. Lot's of hack mechanics/autoparts stores will stick any battery in the car with the terminals in the right place. That's simply NOT good enough for a BMW. And with the later cars, (E70 and beyond), the new battery needs to be coded to the car.

[Stevo96]

I think the battery is the original one! It's the one showing the green, black light.. It's huge!

[Skyline]

Originally Posted by Stevo96

I think the battery is the original one! It's the one showing the green, black light.. It's huge!

So what's the voltage after charging and letting it sit off the charger for several hours?

BTW, if you do this while the battery is in the car and connected, and you get a less than satisfactory result, there's no guarantee you don't have some sort of parasitic current drain. If the result is good, you're good. But if it's bad, you might want to repeat the test with the battery disconnected just to be sure you're not condemning a good, (and expensive,) battery.

[bcredliner]

Originally Posted by Skyline

So what's the voltage after charging and letting it sit off the charger for several hours?

BTW, if you do this while the battery is in the car and connected, and you get a less than satisfactory result, there's no guarantee you don't have some sort of parasitic current drain. If the result is good, you're good. But if it's bad, you might want to repeat the test with the battery disconnected just to be sure you're not condemning a good, (and expensive,) battery.

Or just have the battery load tested.

[Stevo96]

I've had the battery on a trickle charger for the past 2 days - it's still charging! Once it's fully charged i'll report back.

[Stevo96]

Ok, I have the readings...
Just to recap, my battery light is always on and so is the abs trifecta.
My battery died on the drive the other day but I think it was because I had the doors open for 4 hours whilst changing the carrier. It's since been on a trickle charger.
Battery was dead 11.2v
Charged up to 13.16v
After first start 12.53v
After 1 hr with battery disconnected from car 12.6v
Started car after 1 hr, idled at 13.8v
Revved to 1500 and got 13.92v
car is now idling between 13.8 and 13.85v

I don't see what is wrong? These numbers seem ok yet my light is still on. Any ideas?

[Skyline]

You really didn't follow through on that battery test properly. After charging, (via charger or driving the car), disconnect the battery and let it sit for at least two hours, three would be better. One hour is not enough. Then test it with a VOM, not by hooking it up, starting the car and looking at the voltage in the cluster. But the 12.53 volts you got seems a little low, but without the proper test, there's no way to be sure. The minute you start the car, your alternator bumps the surface charge up on the battery, quickly overriding any juice you used starting the car. The problem is that the surface charge will give you a false high reading. A good battery tester will not be fooled by the surface charge. But if all you've got is a VOM, you need to deplete that surface charge fully before testing.

[bcredliner]

It doesn't have to be this complicated. Just get the battery load tested. The alternator voltages are in the normal range.