Need of new battery? If yes, which one?

[Pesca]

After some earlier alerts when it was cold outside (-20 to 25C) and the car had some hard time to start, I finally got stranded leaving work this evening (-25C all day).

A co-worker helped me boost the car and I went home. On the way back, I plugged my scangauge on the car and I could read around 14.4V with the engine running and about 12.1-12.2V without the engine.

Is 12.2V means the battery is nearly dead/ needs replacement?
The car is garaged during the night (about 13C), I drive about 40 minutes to work and leave it in the cold for 9-10h before going back home. So I believe the battery has time to get charged again while driving, but about 10h at -25C seems to deplete it completely (lost the average fuel and average fuel on the inboard computer but not the clock or the radio stations).

Should I change it or should I try to charge it back (I have the Miata plugged on a charger for the winter, so I could use it on the BMW)?

If I change it, what should I take (size/brand)? Nothing said on the owner manual, so I will measure the battery later.

I have some shopping to do at Costco tomorrow, so I could buy one there, or I can stop to a CanadianTire or Walmart which are not too far from home.

Any recommendations?

Thanks for the help.

 

[901Memphis]

I would charge it first and have it tested, it could just be low state of charge.

If you replace it go with the biggest heaviest battery that bolts to the terminals and fits in the hole.

 

[Quattro Pete]

40 mins of driving twice a day should be plenty of time to keep it charged up. Sounds like this battery may be done. Is it still the original factory battery? If so, I think it's time to let it go.

As far as replacements, I bought a Walmart EverStart Maxx H8 earlier this year. People generally have positive things to say about it. It's made by Johnson Controls. I believe the same battery would fit your car, but you may want to double check on some bmw forum.

 

[SrDriver]

Have have good luck with Walmart batteries too.

 

[901Memphis]

Yes it should fit an H8 as the biggest battery commonly available, I would shop around knowing the size you need. The Walmart Maxx H8 is nice but not sure if it's available everywhere.

 

[Oil Changer]

Read every post from member wrcsixeight. He knows what he is talking about and your questions will be thoroughly answered.

From Interstate:

Will driving a car fully recharge a battery?

There are a number of factors affecting an alternator’s ability to adequately charge a battery. The greatest factors are:

1) How much current (amps) from the alternator is diverted to the battery to charge
2) How long the current is available (drive time)
3) Battery temperature
4) Battery age

Generally, running the engine at idle or short stop-and-go trips, during bad weather at night, will not recharge the battery effectively.

In the following situations, the alternator will not adequately recharge a battery:

1. The battery is drained because an interior light was left on in the car for 18-24 hours
2. The battery is drained because the vehicle has not been driven for a month or more
3. The car is only driven at 35 miles per hour to a nearby store and back 2 or 3 days a week

From NOCO:

The battery voltage of a lead acid battery is directly proportional to the number of battery cells wired in series. If the nominal voltage of a typical lead acid battery is about 2V per battery cell, then there is roughly 6 battery cells for a standard lead acid battery.

In general, the nominal voltage of a lead acid battery is roughly 2.10V to 2.13V per battery cell. Thus, a fully charged lead acid battery will have a voltage of 12.6V to 12.8V, whereas, a fully discharged lead acid battery would have a voltage of 11.8V to 12.0V. As you can see, the difference between a fully charged battery and a fully discharged battery is only roughly 1V. However, these values are different from battery chemistry to battery chemistry.

 

[Quattro Pete]

Of course another possibility is that you have a fault in your electrical system somewhere that drains your battery excessively.

 

[Oil Changer]

Here's a gem from wrcsixeight:

I can't claim to have operated any battery testers, but I also don't believe the stores when they are trying to get out of warranty coverage.

The 12.4v could indicate not that the batteries are bad, but that they are not fully charged.

Most people assume the alternator is an almighty near instant battery charger, but the fact remains that taking a battery from 80% to 100% takes many hours and voltages in the mid to upper 14s.

If you have ever needed to jumpstart these batteries, and have not driven the vehicle for at least 6 hours, non stop, then the batteries are not fully charged. Depending on the voltage regulator and the capability of the alternator, and the cabling between alternator and batteries, this 6 hour figure might double.

When a lead acid battery is not returned to full charge, it degrades and loses capacity. The lower it sits below 100%, and the longer it sits there, the faster the capacity is lost.

I'd check your battery cables for corrosion, and your engine ground for corrosion, and the connections on the back of the alternator for corrosion, and this means removal and physical cleaning, not just a quick glance and a declaration that they are 'just fine'.

I'd also get a 10 amp charger and put it on overnight on each battery individually.

I'd hate to be the one to warranty batteries. Batteries within the warranty period are usually killed by improper, incomplete recharging, and the incorrect mindset of the populace that the alternator is capable of the impossible. Which is fully charging a depleted battery quickly. Most of the populace has no idea that the battery for best life needs to stay as close to fully charged as possible at all times either.

Full charging any well depleted lead acid battery takes time, no matter how big and shiny the alternator, and no matter its rating. Hours and hours. No way around this fact.

If you ever need a jumpstart, then a battery charger needs to be employed ASAP and for long enough to get the battery above 95% charged. Not doing this is pretty much a death sentence for a battery, unless drive times are long enough to get the battery up over the 80% threshold. This can also take a long while depending on the alternator and the cabling and what the voltage regulator allows.

So, I am not necessarily hoping you get new batteries for free, their failure could be all your fault, not that of Sears and whomever manufactured the batteries for them.

Putting them on a battery charger and insuring they are fully charged could eliminate your slow cranking complaint and you could possible get years more of life out of them.

Expecting the alternator to fully recharge them is simply folly.

 

[92saturnsl2]

Sounds like you have a bad battery. Voltage isn't the best way to tell, unless you can apply a load to the battery while you measure the voltage. Most auto parts stores will test a battery for free, I would try this before sinking $100+ on a battery.

You can always get a battery simply by telling them the vehicle it's going in, then they can look up the correct size. I usually like to get the most bang for the buck; since batteries are priced similarly, regardless of size, you can often find a larger battery that will fit in the same spot that will provide a larger reserve capacity. This can be the difference between your new battery lasting 5 years, or six.

Most times the battery tray is larger than the actual battery, so you can fit something wider or taller. Measure the opening width and depth (height usually isn't a bottleneck, but if your battery sits up high, or your hood is low, measure height as well). Compare these measurements to a chart online that shows BCI group numbers along with dimensions. Select the largest battery that will fit in the available space. You might be surprised at how much larger a battery you can use-- bigger IS better in most cases, and most times you won't pay any more money for the larger sizes.

 

[Pesca]

Hi,

Thanks for the quick answers, keep them going if needed.

To answer your questions:
- Yes, I believe it is the original one... but my Miata still has the original one... but it uses only in summer.
- Driving is 10 minutes city and then 30 minutes highway (115-120 kph), that is why I supposed the battery should be able to recharge.
- Yes, I thought 12.2V was low. I cannot remember what I have on the Miata (scangauge on it too), as the battery is old, but I believe it is around 12.7-12.8V.
- I don't think I have a faulty electrical system as I don't have any problem when the temperature is above -10C to start the car with the car parked outside and when I left the car garaged for a week last month.

Funny thing how much space they have left to put the battery. I believe they put the minimum sized one in, as there is a bracket to hold it in place and a threaded hole further to move the bracket in order to put a larger battery.

I will research the battery you mentioned and surf the BMW forums.
I measured the actual battery size and the extra space, and I will probably shop for a new battery tomorrow.

 

[HTSS_TR]

Put the charger on the BMW overnight, the next morning disconnect the charger and if after 30-60 minutes the battery has less than 12.5 volts it is dying.

You should also check the static drain, with key off and nothing on it should drains less than 0.01 A. With only dome light on it should drain 0.2-0.3 A.

 

[Pesca]

Originally Posted By: Quattro Pete

As far as replacements, I bought a Walmart EverStart Maxx H8 earlier this year. People generally have positive things to say about it. It's made by Johnson Controls. I believe the same battery would fit your car, but you may want to double check on some bmw forum.


QP, did you register your battery?

Surfing BMW forums, I read this and could not believe it until they linked this page .

Truely german engineering, but if the car adapts itself to an aging battery, it should recognize the same way when it has a good battery, no?

 

[Quattro Pete]

Originally Posted By: Pesca
QP, did you register your battery?

Surfing BMW forums, I read this and could not believe it until they linked this page .

Nope. Mine is an older model that does not require any of these shenanigans.

 

[Kira]

Hello, I was going to warn you about BMW's batteries with "smarts". My friend has one.
Your link showed me more than I knew about them.
I got the idea that "power hungry Saabs" should sleep charging.
Maybe it's a prudent thing for all of us to do? ...cars above a certain age? Kira

 

[Quattro Pete]

BTW, realoem lists the same battery part numbers for both mine and your bmw, so I'm pretty sure the Maxx H8 I mentioned earlier would work. Costco may have something comparable for less money.

But there is also an AGM battery available on yours...

http://realoem.com/bmw/showparts.do?model=PK53&mospid=51052&btnr=61_1999&hg=61&fg=30

http://realoem.com/bmw/showparts.do?model=DT53&mospid=47587&btnr=61_0146&hg=61&fg=30


BTW, realoem also mentions having to register the battery on your car.

 

[eljefino]

OP's in Canada and his WM might have different battery distribution than in the states. Just FYI.

There are charts of battery state of charge at a given temp. 12.2 seems low but at -25C maybe not. This chart doesn't go to -25C but you'd look to be around 60% SOC:

So, +2 on the "Throw ten amps at it overnight".

 

[Pesca]

Aaahhh, seriously!! Registering a battery?

Yes, I checked on the forums and it is written the H8 should fit in my car.

Eljefino, thanks a lot for the chart. I will check tomorrow morning, after a night of charging what is the SOC of the battery. At least, temperature will be in the chart, no need to extrapolate . And yes, Walmart canada sell the H8: The closest to home is on limited stock, so close to 0, but one 10kms away has it in stock.

HTSS_TR, battery is charging and I will do your check: disconnect it when I get up and check the voltage when I will leave home, about an hour later.

Thank you all for all your help, that is really appreciated.
I will continue to update this thread.

 

[cashmoney]

Costco or Walmart stock pretty decent batteries at good prices. Both companies offer full replacement 3 year non-pro-rated warranties. Non-pro-rated warranty is the only kind of warranty that is work the paper its printed on. Pro-rated battery warranties are worthless, over hyped marketing bull-poop.

All things being and obviously within reason, a bigger, heavier lead-acid wet cell battery will perform better and last longer in your car than a smaller sized battery. Buy biggest heaviest battery that will fit with no issues.

My car (2006 model) has a ginormous old school Panasonic battery (made in Japan) in it that is 9 years old and still working great.

 

[JimPghPA]

1) How accurate is the volt meter you used to measure the battery voltage?

2) 12.2 may not be too low of a voltage for a good battery if it is not fully charged, and it may not be fully charged.

3) On very cold days an engine with 10W-xx oil in the crank case may crank slower than an engine with 5W-xx or 0W-xx. 0W-xx is the best oil for cold weather starts.

 

[Quattro Pete]

Originally Posted By: JimPghPA
3) On very cold days an engine with 10W-xx oil in the crank case may crank slower than an engine with 5W-xx or 0W-xx. 0W-xx is the best oil for cold weather starts.

And as per his signature, he is using 0w-30.