Need alt and batt

[ATB88]

Battery light came on while driving home from the beach last night. Checked voltage on ibus app, was below 12, and down to about 10 by the end of the drive with lots of other warning lights going haywire. Weird that the battery failed so suddenly, it was only 3 years old and hadn't faltered in that time.

Anyway, I need the car today so I need to buy an off the shelf battery somewhere this morning. Any recommendations? Any particular place have a better warranty than others?

Thanks!

EDIT: Looks like I need both an alternator and a battery.

For alternator should I go Valeo OEM from FCP, or Bosch OEM from FCP? Valeo appears to be brand new, and the product page for the Bosch seems to say that it's a re-manned Valeo, and requires a core charge? Any reason to not get the new Valeo?

https://www.fcpeuro.com/products/bmw...eo-12317831436

https://www.fcpeuro.com/products/bmw...-z3-m3-al9407x

[eacmen]

The voltage dropped while you were driving? Might be alternator.


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[ATB88]

The voltage dropped while you were driving? Might be alternator.


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Yeah. Started fine, then halfway through a 60 mile drive the red battery light comes on, and voltage is in the low 12s. By the time I got home it was lower.

After I shut the car off, though, it wouldn't start again without a jump. Wouldn't that indicate battery, as the alt isn't involved in starting? Or maybe the failure of the alt drained the battery while driving which is now causing no start?

[eacmen]

Yeah. Started fine, then halfway through a 60 mile drive the red battery light comes on, and voltage is in the low 12s. By the time I got home it was lower.

After I shut the car off, though, it wouldn't start again without a jump. Wouldn't that indicate battery, as the alt isn't involved in starting? Or maybe the failure of the alt drained the battery while driving which is now causing no start?

Alternator charges the battery while driving. But also powers the vehicle at the same time. Without the alternator the whole car is just running on the battery, so it makes sense why it would be dead.

Charge the battery and take it to autozone or similar. Most can check batt/alternator for free. If you have a multimeter you can check it yourself as well.


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[Phoenix///M3]

I dropped in one of these in March. $174 from Pep Boys at the time.

Bosch Platinum Series AGM Battery Group, Size H7/L4/94R



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[eacmen]

https://youtu.be/LGB6ZEjGm7Q

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[bigjae46]

Sounds like an alternator. If the voltage dropped to 10v while driving...it’s an alternator.


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[Xmetal]

I dropped in one of these in March. $174 from Pep Boys at the time.

Bosch Platinum Series AGM Battery Group, Size H7/L4/94R



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Pep Boys no longer carries the Bosch brand - they have switched to Champion

[Obioban]

You need an alternator.

[Maxima SE]

Battery light came on while driving home from the beach last night. Checked voltage on ibus app, was below 12, and down to about 10 by the end of the drive with lots of other warning lights going haywire. Weird that the battery failed so suddenly, it was only 3 years old and hadn't faltered in that time.

Anyway, I need the car today so I need to buy an off the shelf battery somewhere this morning. Any recommendations? Any particular place have a better warranty than others?

Thanks!

There are 3 places I would buy a battery for my car.... in this order:

1) Costco... Because interstate batteries are among the best. You'll get the best deal and price as well. They dont always have them in stock and you will need a membership
2) Walmart, rock bottom pricing and 3 year warranty. arguably lower quality battery than costco but also the cheapest battery you'll get your hands on
3) advance auto parts (carquest in cali) with 25% off online coupon... comes out to roughly the price of walmart, maybe a little more.

forget about autozone/orielly/sears etc... you'll pay out of the butt without a coupon. most of these batteries are all coming from the same factory (except maybe interstate).... you just get a different warranty/label depending on who you get it from.

[ATB88]

Thanks guys.

Indeed, I need an alternator. Got it to OReillys and their diagnostic device told them my voltage regulator's toast, and also that my battery is completely dead.

So, I definitely need an alternator. Gonna go FCP OEM. Valeo appears to be brand new, and the product page for the Bosch seems to say that it's a re-manned Valeo, and requires a core charge? Any reason to get the re-manned Valeo (sold as Bosch) over the new Valeo?

https://www.fcpeuro.com/products/bmw...eo-12317831436

https://www.fcpeuro.com/products/bmw...-z3-m3-al9407x

OReillys guy said I also need a new battery. I guess the car driving purely off the juice of the battery killed it? Is there a chance my battery's actually okay? On the way back from OReillys, the car completely died and had to jump it again to get home. Currently have it hooked up to my CTEK charger until my new alt gets here in case it can be saved. If I do also need a new battery is whatever cheapest generic battery of the correct size/specs (from, say, costco or walmart) the way to go?

One last question: could a soft-failing alternator explain intermittent hard starts that I've been experiencing over the last 8 months? Wondering if this is possibly connected to that issue or is if this is just be a coincidence. Would be really great if a new alt solved that problem too... but it seems unlikely since the alternator isn't involved at all in starting... or is it??

[yhp2009]

I got a valeo alternator from fcp just a few months ago. Easy diy and no issues thus far

[bigjae46]

Rebuilds seem to be hit and miss. I prefer a used OE alt over a new rebuild but that’s just me.


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[COVID-19]

For battery get it at Costco

[eacmen]

Rebuilds seem to be hit and miss. I prefer a used OE alt over a new rebuild but that’s just me.


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Concur. Get it from FCP so if it ever dies you can just get a new one.