reviving my 9 year old OEM battery?should i try

[omodos]

ok ladies and gents don't srone me to death but I recently changed out my OEM battery it was an 2004 battery, now the little indicator 'bulb' was on black so meant insufficiently charged...but did start although somewhat laboured, and so pre-emptively swapped it out cos of my 'cold' start issues as mentioned in previous posts....

now just curious should i stick it on a battery charger and see if it ever reaches green and fully charged?

ps the oem battery weighed a tonne comapared to the bosch replacement...is it a case of oem being better or technology getting lighter and more efficient, more energy pound for pound......

[Ricky Bobby]

I would make sure the battery was fully charged (the new one) before swapping out the old and new. Sometimes the batteries sit on the shelf a bit and lose some of their charge.

Fwiw, previous owner changed out with a bosch 2 years ago and I haven't had a single issue.

[X5SND]

I wouldn't bother. Unless you need a "utility" battery for something that doesn't need to be reliable I'd just chuck it.

[upallnight]

You would need to remove the old battery acid, de-sulfate the plates (need a special charger) rinse the battery. Afterward you will need to install fresh battery acid charge the battery. If you are lucky the battery may hold a charge.

[TerminatorX5]

exactly what upallnight said - to revive that battery, you need to refurbish it, simple recharging will not bring it back to life...

years ago, there were shops in harbors that specialized in marine batteries from big containerships and oil tankers - those batteries literally weighted a ton (or two) and it was cost effective to refurbish them... those shops would take an automotive battery and refurbish them too, as a side job under the table - but at the time and place, a replacement battery was hard to find... now days, those car batteries are disposable items...

[tmv]

Don't bother.

[StephenVA]

Having done this "band aid" battery reconditioning myself in my college days with no money, I can tell you first hand the results will be a 90 day life max. The first challenge you will discover is what do you drain the battery acid into? A plastic bucket works, then what? Dump it in a county park somewhere?
Rinsing out the battery without losing all your pants and shoes to battery acid damage is the second challenge. The scaling trash from the battery plates that comes out is interesting and it will give you insight into battery construction.

Charging up a battery that is on its last legs is an interesting project, but is was "fully charged" in the vehicle, as the battery in question could only hold a surface charge that was approx 20% of its original capacity. This is why it cranked slowly. Low available amps reserve in the battery.
Bottom line: lots of effort = poor back up battery.

Education time J
Here is the proper way to test a battery.
Charge up for 2-6hrs using a 4-12 amp charger, (if you own a 40 amp commercial charger you can actually do a volt test when charging after 3 mins…over 15.5 volts? Trash it) apply a load of 50% of cold cranking amp ratings (0 degree ratings not the 80 degree rating used to sell you the battery). For most batteries a 150-250 amps load will expose battery state in 15-30 seconds. Hold load draw for 15 seconds while noting battery voltage at the beginning and end of test.

Starting voltage 12.7 or higher
Draw reading should NOT drop below 10 volts
If battery drops below 9.6 volts, throw in trash/recharge and retest, replace if fails again.

All of this can be done in a car or outside on a bench with proper test equipment. For a by the side of the road quickie test, all that is needed is a voltmeter. Read battery voltage with key off >12.0 volts? Snap on headlamps on high for 30 seconds battery voltage >9.6? Start / jump-start vehicle, read voltage at battery terminals >14.7? Charging system is OK. Replace/charge battery.

We will not get into starter draw testing on this posting, as I am sure eyes are glazing over already. We will also not get into battery testing on ones that short out internally, as the reading go everywhere but to a normal range. Ever seen 20 volts on a car battery?
It makes electronics go nuts in our cars. The fun ones are the ones that will not jump when connected to the car as the battery is shorted/dead and consumes all the voltage from the cables. Disconnect the battery cables from the installed battery, jump directly to the battery cables and presto the car starts.

Never run a car without a battery connected as the shock to the regulator will not be good.

Special note to everyone now that winter is here. NEVER jump anyone with the “good” car running. The shock to the electrical system will wipe out something 40% of the time. Just hook up the cables, run the good car without trying to start the dead one. This will charge the battery on the dead one with little chance of damage to either car. Charge for a few minutes and turn off the good car and crank the dead one. Should start right up.

Class over, click next posting….

[TiAgX5]

In your "Does a weak battery cause problems?" inital post you stated that the battery had starting issues when the cold weather hit last year, you pushed the battery thru winter and another summer. Due to this fact, I doubt an acid swap/de-sulfate cycle would save the battery. Once a neglected battery dies, it's dead. Let it go.

A computer controlled smart charger tests a battery and de-sulfates when needed. I use a Schumacher SC-1200A charger about once a month. Around every 2nd or 3rd month the charger will run a de-sulfate cycle. The battery is 3 yrs old and when fully charged and parked in the garage (alarm off) for 24 hrs, a voltage check will read 12.9 volts. An added bonus of regular charging is long alternator life, 175k miles and still OE (shows 14.2v output at cigarette lighter plug while runnung). Another bonus is fewer burned out bulbs and brighter lights, I run the fogs as DRL (on while driving, hate the dim DRL high beam look) and the truck has only had 1 fog bulb burn out.

[omodos]

appreciate all the replies, seems general consensus is let the oem old battery go, and either way temps are now down to 15c and car started fine with new bosch , whereas at a temp of 19c it would not start up with the old oem battery.....temps rarely go below 5c in winter in the coastal regions...but am planning on some hitting the mountains and snow, so will be interesting to see how it holds up...again thanks for all the replies...last note....what out of all the items on x5 would drain most current? pano sunroof? xenons? window lifters? or the window heater at rear?or the horn (i killed the battery on my merc after over enthusiastically honking all night long after a soccer match win)

[racingbmwm3]

Of all the electrical loads, the resistive heater loads will be the biggest single draw, but your lights as a collective (fog, parking, tail, sidemarker, headlights) would be up there also.
I know with my wife's short commute during the winter, with the car full of kids, all 4 heated seats on high, all the lights on, windshield wipers on, front and rear heater fans blowing, the battery never really gets to recharge itself after starting in the morning. So, if we don't make any hour+ drives over the weekend, the trickle charger gets hooked up overnight.

FYI, your xenon's are about half the load of standard halogens.