tonyb635

It's a very interesting system and there is some BS in it... mainly when it comes to what the dealer charges you. The registering part tells the car that a new battery is in and it is supposed to adjust the charging towards the new battery which would probably be less than what was required by the old battery therefore not over charging and damaging the battery. If you change the battery specs and or from Non-AGM to AGM then this would be IMO something I would want to have corrected in the system since batteries do charge differently. My point of not paying to register the new battery is only that if it stops performing correctly it could be replaced and for five years this is three more than if the strealer installed it, so I personally don't see a reason to register, but of course this would be up to the owner. BMW batteries are only a two year warranty and I have heard they are only covered if they install and register it. You can also read quite a few horror stories here where people did not register etc and have had lots of problems. I don't know the details but my guess would be that it was a totally different battery instead of one that was exactly the same.

Maini

I highly recommend swapping the AGM battery with a FLA battery at AutoZone with the exact specs as your original battery. This would remove a lot of risk to start with. Then either register it yourself from the links sent above ... go to an Indy to register it for $50 ar do not register it and see what happens. But keeping an AGM battery in a car which does not know how to deal with it is probably too risky!! My car was under warranty and was converted to an AGM battery by the dealer for free and he had explained me.. no reason to not trust them. Also do look up this on the other forms.. lot more details there..

maruzo

My 2010 535xi came with a white battery as well. It's now losing charge rapidly after I store the car (i typically drive it during weekend only).

It is hovering around 12.1 ~ 12.2 the day after I drove it. I'm attempting to use battery tender to boost its charge. We'll see if that does the trick.

I've heard of the possibility of reconditioning the battery with distilled water and epsom salt.

I'm gonna attempt it by connecting a spare battery to the + and _ posts under the hood, then remove the trunk battery. Once removed from the vehicle, I'll attempt to refill the battery with distilled water and epsom salt, then charge it again with the tender.

Has anyone tried this procedure yet?

BimmerFan52

Several things:

First, your battery acts as a filter for your electrical system, absorbing voltage spikes and surges. If you connect a temporary battery to the car do not start the car as you have changed the location of the battery in the circuit and it will no longer act as a filter.

Second, adding chemicals to the battery will at best give you a slight boost in performance for several months. It is a stopgap to squeeze a little more life out of the battery. The risk is you are handling a dangerous mix of chemicals that can explode. While working with the battery wear at least eye goggles, and better a face shield. Also wear heavy rubber gloves that extend up your forearms.

I would suggest you buy a new battery that is oversized (not physically but in amperage rating) and purchase a good quality trickle charger that you can use to maintain the battery.

Each time you start the car the amps used must be charged back into the car. If you use it on the weekend to run errands and start the engine four or five times but only drive it a short distance you never fully recharge it. Batteries that are always undercharged will deteriorate very quickly. Try to put a little distance on the battery before you put it away on Sunday and then hook up the trickle charger.

I have attached a couple of battery resources.
Additives to Boost Flooded Lead Acid – Battery University

maruzo

Thanks for the good tips Bimmerfan. I'll make sure to follow the safety protocols.

My weekend runs typically consists of 20+ highway miles each trip, so the car does get a chance to sufficiently charge the battery. However, the car's close to 4 years old on its oem battery, so i'm guessing it's in its twilight period.

Sad but what else can you do. I would love to keep everything stock, including the battery. But oem are so expensive. 600 plus and you only get 2 years warranty?

Anyway, i use battery tender plus, which has been pretty reliable for me. Not sure if there's a better brand out there. I also have a Century charger, but its 2amp low charging mode doesn't charge as good as the tender unit. I used the Century overnight at 2amps and the voltage went from 12.1 to 12.2. With the tender unit the charge is now at 12.55 (after a good 8 hours charging).

I'm hoping after I get home tonight the charge will be complete.

Btw, any god tips on how to test if the battery is actually holding the charge? I've read here that you can test it by doing some simple start/ stop manuevers.

BimmerFan52

If you test the battery right after taking it off the charger you can get a false "surface charge" reading. To remove the surface charge, you can leave the battery sit off the charger for three hours. Or if you want to test immediately after removing it from the charger, turn and leave your high beam headlights on for five minutes without the engine running. Then turn them off and let the battery sit for five minutes without the engine running. Then measure the voltage for a more accurate reading. In the attachment I provided in my last post on this thread there is a chart that shows the voltage reading and its relationship to approximately charge of the battery.

Don't worry about not using the OEM battery. BMW doesn't manufacturer batteries. In facts the hundreds (if not thousands) of different brand name labels slapped on batteries are on batteries nearly all made by only five major manufacturers.

East Penn Manufacturing, Energizer Holdings, Enersys, Exide Technologies and Johnson controls manufacture nearly every battery in the US, as well as many that are used overseas and many that come into the US from overseas in imported vehicles, including BMW.

Douglas Battery Manufacturing produced batteries for BMW in the past. They were acquired by East Penn Manufacturing sometime back. I am not sure if East Penn still holds the contract but you can be sure it is one of the five shown above.

The exact battery used in your BMW can be purchased (usually under a national auto parts chain private label) by doing a little research and searching numbers off labels on your battery on the Web.

Jrosa55

My new non-registered battery is still working great so far. I only used it for 21 days but went from Chicago to Florida (1,800 miles) with no problems. I do keep a trickle charger connected when the car is not in used. I remembered when when my car left me on the side of the road and the Toyota maintenance manager help me out with a jump. I told him that I was shocked that having a such an expensive car and I still needed to connect a charger to it when not in used. He said to get used to it due to todays vehicles requires fully charge batteries to support all dormant/living electronics. I recommend to fully charge the battery, on the battery itself and take it to AutoZone for a free diagnostic check. That's were I found out that the battery would not hold a charge. Bought a new battery and called it a day. AutoZone sells the BMW OEM battery equivalent. Another option would be call the local non BMW equivalent shop and ask for a OEM battery cost. They usually offer it for a reasonable price. Read the beginning of this thread.

L337E60

I'm actually surprised that the car left you stranded because of a bad battery. The alternator should have kept the car running, even with a bad battery.

Jrosa55

The battery was not holding a charge. Replaced the battery and the problem disappeared.

Jrosa55

Btw, I never registered the new battery. All is working find so far. Stick it to the man.