daven

Today I had the battery replaced (at the dealers) it had been playing up whenever the OAT dropped and the car was parked up for a couple of days. It would manifest itself with odd run flat monitor failures and/or transmission fault. If the car was left idling for a couple of minuites and then stopped/restarted all the failures would clear. What prompted me to finally sort it was on start-up. 'Charging fault' with idrive warnings of battery not charging blah blah blah!
Checking the voltage prior to start up today it was 12.2 v and 11.7v with the head lights on. With the engine running the voltage output from the alternator was 15v So it looked like a 'lazy' cell. (It was positively summer here today with +8C).
Now, having got the battery replaced WTF is registering the battery to the car all about? (besides the extra ?47 on the bill!)

mikeg3tsguap

its called the bend over charge lmao

mag75

This has been an unresolved topic on the forum but my opinion is that it is complete BS. Lets think about this here. Does the battery have a computer? NO. So, assuming you put the same battery, with the same voltage, etc etc.... then how the hell would the computer be able to distinguish it from the old or new battery?

I replaced mine about 2 weeks ago from batteries plus and havent had a problem. I think where you might run into trouble is if you install a battery that is not as large or has smaller or larger voltage.

skylolow

I tend to think its also a little fishy.

According to BMW when a battery is registered (say from when it comes of the assembly line) the system begins to monitor the battery and for some mythical reason over time it knows it takes "x" amount from the alternator to keep this battery charged fully. Without registering the new battery according to BMW the system would charge it at this "x" amount of what the old battery was taking to charge. A new battery should hold a charge better and not draw as much off the altenator as a 4 year old battery so the system could end up over charging the battery.

Well a 12 year old can see how there is many holes in this theory. I highly doubt anyone would design a system so flawed and if they did we should not be buying cars from people like this.

Bottom line in it all is it doesn't matter if the battery is one day old or 5 years old the system must adjust for charging under load in various conditions daily. You can't just say the battery has been drawing "X" amount over the last month so its only charging it at "x" amount. You'd have so many battery/charging issues it would be a nightmare.

Anzafin

I don't know about the real "need" to register the new battery, but I took my car and my new battery to dealer for registering today.
I changed it myself couple of weeks ago and everything has worked fine, no issues. The old one was 90Ah and the new is 100Ah.

I was with the technician when he did the registering and he asked me if I wanted to tell the car about the new capacity. I asked him what would he do and he replied that it could be left as it was (90Ah), if everything has worked fine. So we left it in 90Ah. Just "registering".

They took 32€ of it, so necessary or not, I can go with this "need to register" at this price.

edit: And we read the recorded fault codes at the same time so only this is worth that 32€.

tbal

I just replaced a battery, only thing that happens is you have to reset the active steering because the light comes on. Other than that, registering a battery is wack of BS

mikeg3tsguap

good because i plan on ordering a battery this week

tbal

dealership is full of bs period. Make sure the battery you get is from bmw or a exact oe replacement that is atleast 850cca.