New battery time? (video)

[97tbird]

So i checked the voltage of my battery (OEM factory, 6 yrs old), using the OBC of my Bimmer E46.
The video shows voltage at ON position 1st, then how the voltage goes up after starting...

the car was driven about 24 hrs before this 'test'...i was told it should show at least 12.5 V in 'on' position...mine (see vid) started at 11.3 and then was 11.9 or so when I started filming (so you won't see the 11.3 at start, but 11.9), and then AFTER STARTING crept up to like 13.9 or so...

AAP test said "needs charging" after driven about 30 miles, but not 'bad'. Temps are dropping and the car doesn't get driven a lot, and last start was kinda 'rough'...

Here's the vid:

 

[user52165]

12.6 volts is the test standard. It's time is up, it's over. 6 years is good service. Weather will get colder. Bite the bullet before you get stranded at the worst moment.

 

[Quattro Pete]

In my experience, 11.9V is perfectly fine in these cars when alternator is not running. When I bought the car, I didn't know how old the battery was and it was showing about the same voltage as yours, so I thought I needed a new battery. When I installed a brand new battery, it also showed the same voltage.

So, just looking at this voltage display is probably not enough to determine whether you need a new battery or not. A proper load test would probably be needed.

If you're still on your original battery, then I'd say go ahead and get a new one, rather than waiting for this one to die at the most inconvenient time.

 

[Bluestream]

I check the plates and see how sulphated they are; That will tell you a lot

 

[Lead Shoes]

My Honda's battery registers in at 9 volts right after it was running with a voltmeter, it still turns the car over... come to think of it I should look into a replacement lol...

 

[Quattro Pete]

Originally Posted By: 97tbird
mine (see vid) started at 11.3 and then was 11.9 or so when I started filming (so you won't see the 11.3 at start, but 11.9),

By the way, my 3-year-old battery shows 11.5V (from Test 9) in the instrument cluster with the engine off. However, when I check it directly with a volt meter, I get a reading of 12.1V.

 

[Donald]

I would not replace it on voltage alone. Get it fully charged with an AC plug-in charger if needed and do a load test of half the rated CCA for 15 seconds, looking at the voltage just before you stop the test. Temp compensate the voltage if not around 70. Thats close to the best battery test.

Having said that I'll bet you need a new battery. But I would not fork over the dough without a load test.

BTW the voltmeter in your car's computer is no where fast enough to measure cranking voltage.

 

[Papa Bear]

6 yrs ... change it, NOW

 

[tommygunn]

Originally Posted By: 97tbird
AAP test said "needs charging" after driven about 30 miles, but not 'bad'. Temps are dropping and the car doesn't get driven a lot, and last start was kinda 'rough'...
Something is going wrong with your electrical system (alternator...or etc...) then. if you took the vehicle for a good long drive, the vehicle SHOULD have kept that battery at full change......

Let them do the "load test" - where they tell you to raise the idle, settle the idle, flash the high beams, shut off the high beams, etc....while the vehicle is RUNNING and that will give you a diagnostic read out to give to a mechanic....

The "ripple" should typically be below 80....anything higher, and it'll slowly kill your battery over time....

Originally Posted By: Papa Bear
6 yrs ... change it, NOW
Goood idea

Down here in the south, we are lucky to get 24 months out of our batteries! So if you got 6 yrs out of yours, perhaps it IS time for a change.....BUT, before dropping money on a new battery, I'd definitely get your "charging system" diagnosed.

As you should know, the battery in the vehicle is merely used to turn over/START the vehicle, once the vehicle is started, the alternator takes over, keeping the vehicle charged.....to me it sounds like you may have a failing "charging system" - i.e.: it's on a "crutch" right now, and it's powering off the battery perhaps because the alternator can't "keep up".

 

[97tbird]

I thought the altenator should be in good shape as the voltage changed to 14 or so as soon as the car was started - and was 11.3V before, with the car NOT running... ??

or am I misunderstanding something.

Today, I drove to work (about 40 min drive but at much higher speeds) and tested immediately after shutting engine down...it was 12.3 V

 

[HTSS_TR]

If the voltage is only 12.3v after 40 minutes drive, the battery is at/near the end of its life. I would start looking for replacement, Motorcraft BXT series battery has good warranty, 36 months free replacement and 100 months pro-rate at reasonable price at around $9x.xx at Ford dealer in So Cal, your local Ford dealers may have lower/higher price.

 

[97tbird]

Thanks - I was going to go with Autocraft Gold 94 series from Advanced AP, as I have a coupon, and they will install it for free, etc...

But I will take a look at Motorcraft ones, too...
EDIT: I think they only make for Ford ? How can I find a cross reference of a different series for BMWs from another manufacturer?

 

[HTSS_TR]

I bought Motorcraft BXT-49 for my MB E430 few months ago for $93.xx plus tax. You need to find the battery size for your BMW then call local Ford dealers or check availability on line at Fordparts.com

 

[Bluestream]

Originally Posted By: Papa Bear
6 yrs ... change it, NOW


A had a battery last 12 years in my BMW

 

[sciphi]

The OEM battery in our Fit lasted 3 years. As always, YMMV.

 

[Donald]

Originally Posted By: 97tbird
Thanks - I was going to go with Autocraft Gold 94 series from Advanced AP, as I have a coupon, and they will install it for free, etc...

But I will take a look at Motorcraft ones, too...
EDIT: I think they only make for Ford ? How can I find a cross reference of a different series for BMWs from another manufacturer?


If the guy installing it at AAP does not shave yet, watch and make sure he does not super tighten the hold down bolts/nuts with a BIG wrench.