Battery Replacement Query

[raptert]

Hi,

I have next to no knowledge with cars.

My car recently had an issue with the battery so I bought a new battery and got a mechanic to replace it.

Obviously because the car was disconnected I had to reset the date/time etc but the mechanic didn’t do anything else.

Having a Quick Look recently when checking over replacing batteries in cars, I have seen that maybe something might need to be coded or something to register the new battery? Should my mechanic have done this because after installing the new battery they didn’t do anything further.

The car is a 2011 BMW 125i (E82).

Thanks in advance!

[RockCrusher]

Think there is more to BMW battery replacement than just setting date/time afterwards.

Link:

https://www.bimmer-tech.net/blog/ite...d-registration

[ctcarbonari]

Originally Posted by RockCrusher

Think there is more to BMW battery replacement than just setting date/time afterwards.

Link:

https://www.bimmer-tech.net/blog/ite...d-registration

^Nice link^

To clarify a bit there's (2) processes. When you replace the battery "in kind", i.e. the same Ah rating and specs as your previous battery then you'll only need to register the new one. If you replace the battery with a higher or lower capacity (different Ah rating) then you'll need to Code the battery.

In layman's terms:
Registration - Tells the car "hey, this is a new battery. Charge it up accordingly"

Coding - Tells the car "hey, this is a different rated battery. Change the rate at which you're charging it up"


Usually only registration is required and does not need to be performed immediately after installation but should be done sooner, rather than later, to maintain a longer lifespan.

Both processes are VERY simple to do with most scan tools that are made for BMWs. For the cost of paying someone else to register your battery you'll be able to buy a scan tool and do it yourself. Then you'll have an invaluable tool that will help you in the future (read/clear error codes, reset service indicators, dispaly sensor values, etc)

[BMWCCA1]

I still contend that neither procedure is truly necessary. If the car is so "smart" that it requires being told whether or not a battery was replaced in order to charge it properly, how smart can it really be? How does the charging system differentiate between the battery your car came with and that same battery five-years later? I have the ability to "register" a BMW battery and still think it's basically bunk. I put a new battery in my wife's E90 when there were parts shortages due to the Pandemic. I went with one of the higher-output batteries at the dealership where I worked. One of the techs told me they'd have to re-program the car for the new type of battery. When they went to do it the existing hardware in the 2008 BMW didn't offer a selection that fit with the new battery. They told me not to worry about it. Several years later and it hasn't seemed to make any difference!

[///MPhatic]

The battery should always be registered, just in case.

This is because the older the battery gets the more charge it loses during use, and thus the more charge the DME (ECU) sends to it.

It's possible that with some BMW's the DME could over-charge the battery, therefore shortening its life.

However, supposedly the DME is constantly checking the voltage so there shouldn't be a possibility of over-charging.

This is why I say err on the side of caution and register the battery.