Need alt and batt

[JayVee]

I bought an Exide AGM Marathon Max. AGM or Absorbed Glass Matt batteries are better due to longer life and typically more power. They are sensitive to deep discharges, however. To be honest, most batteries in the USA come from a few, large suppliers. There are only a handful of approved battery manufactures.

[foolio]

FWIW I just got a battery for my e39 wagon (528iT) and based on Project Farm video I went with the Walmart Everstart. It even says made in Germany on it and we all know that automatically makes it better

[sapote]

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.

OReillys guy said I also need a new battery. I guess the car driving purely off the juice of the battery killed it?

I know it's a 2 months old post but I want to point out something hopefully this can help other member in the future.

1. Are the battery free test at auto parts stores reliable? In this case the OP's battery had been discharged to 10V but it wasn't dead as he thought or as the guy at O'Reilys said. So do your own research before spend your money on new parts.

2. It's not a coincident that both alternator & battery are bad at the same time.

3. Get a voltmeter and check these parts yourself.

[Maxima SE]

I bought an Exide AGM Marathon Max. AGM or Absorbed Glass Matt batteries are better due to longer life and typically more power. They are sensitive to deep discharges, however. To be honest, most batteries in the USA come from a few, large suppliers. There are only a handful of approved battery manufactures.

While this is true, I think the quality of internal components may vary. Either way, I've learned my lesson over the years and now I just buy the one that is either cheapest or has the longest warranty. Champion from pepboys is the only one that has a 4 year warranty and also just about the cheapest option with 25% off. everything else in the market has a 3 year warranty. Second place goes to costco's interstate in terms of price... and I think those batteries are probably the best on the market.

[bigjae46]

Best battery to buy is a car audio battery. I have a Stinger SPV69 battery in my track car that is 11 years old. It’s been discharged at least 10 times. It sits a lot and still starts the car. Needs the help of a maintainer first a day or two if it sits for a couple of weeks.

Car audio batteries are just about the toughest around. An Optima is not a car audio battery.


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[Rkymtnrider]

Best battery to buy is a car audio battery. I have a Stinger SPV69 battery in my track car that is 11 years old. It’s been discharged at least 10 times. It sits a lot and still starts the car. Needs the help of a maintainer first a day or two if it sits for a couple of weeks.

Car audio batteries are just about the toughest around. An Optima is not a car audio battery.


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Ive got an optima yellowtop in my toyota. Put it in when i did my sound system when i bought the truck in 2008. Still running that battery 12 years later. It has been drained completely on multiple occasions after getting an audi avant for my daily. Slap a charger on it and still holds the charge. Now i use a maintainer in the winter. Put a yellow top in the m3 last summer and leave it on a maintainer when not using.

[Arith2]

I bought an Exide AGM Marathon Max. AGM or Absorbed Glass Matt batteries are better due to longer life and typically more power. They are sensitive to deep discharges, however. To be honest, most batteries in the USA come from a few, large suppliers. There are only a handful of approved battery manufactures.

They are not sensitive to deep charges. That's what makes them better mainly. There are weight savings also considering they're fiberglass. Lead acid release hydrogen when charged and if you know chemistry, you know how flamable it is. They're more sensitive to being overcharged and charged too quickly. That's why there are special battery chargers for AGMs. You can destroy one simply by hooking it up to the wrong charger. I've many european cars break down and someone decimates their battery by trying to jump it. Do not jump an AGM. They also don't like heat but our batteries are in the trunk so no big deal for us. AGM is worth the cost. They're 50% more in cost but last at least 300% longer.

As for manufacturing, there's a big company that makes like 90% of the batteries however, Bosch makes their own. I haven't looked in a while but I think AC Delco batteries are Bosch made as well. I don't believe all batteries are created equally by the same manufacturer but the same company that makes the garbage Walmart battery makes OEM batteries for just about everyone. This includes BMW. It's like some Czech company or something. These automotive parts stores buy the cheapest batteries and sell them for quite a bit of profit. An Orielly's battery is made right next to a NAPA, Interstate, Optima, and so on. It's basically a monopoly.

[sapote]

I replaced the alternator and all the belts. When I test the battery using the OBD, it shows as 12.5V. It does take a long crank to start, when it does finally start up, the reading shows at 11.5 and then back to 12.0-12.3.

Checked the regulator and the the positive bolt. It seems like my negative ground bolt was loose. Voltage now reads on the OBD as 13.7. At the terminals under the hood it was more than 14.

If the batt negative bolt was loose this bad for only 12v reading, then I don't see how could the engine be cranked with starter. Mystery to me.

[sc_tr0jan_m3]

The battery light coming on is almost 99% of the time the alternator going bad based on how that light is triggered.

I just had mine go off and after only an alternator replacement, it’s fixed.


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