Registration vs coding a new AGM battery
 

First, this is not a registration vs non-registration question. I believe 100% in the importance of registering a new battery. My question is different...I have searched countless threads but not found an answer yet, hence this new post.

Background:
- I replaced the original factory battery in my 2008 550i when it failed 18 months ago.
- The replacement was an OEM AGM from Batteries+.
- I had an indy register that new one a few days after that install. I specifically asked that they check and make sure the battery was recognized as an AGM because I think the one it replaced was wet cell. They said they coded it was AGM, but I cannot confirm.
- They assured me all was good then, but I did have a faint feeling that maybe they just had registered and not coded the change in type from non-AGM to AGM.
- A few months ago I started getting wonky codes and starting issues and such.
- Batteries+ warrantied me with a new AGM.
- I have the Bavarian Technic tool and registered the new battery this morn (I did not have the BavTech tool the last time.)

My question based on background info above:
- If indy only registered the first new AGM but did not code it in my cars system as AGM (vs wet cell) could that have caused that first one's early demise? (B+ guy said that is only the 2nd or 3rd AGM warranty he has seen in 5 years.)
- How important is coding AGM vs nonAGM as long as the new battery registration is done?

Why? Hoping the BavTech registration is all I need because that is done. If taking it to my new trusted indy is necessary (to resolve AGM coding definitively), then that will cost me time and another $85.

Thanks in advance for any insight.

Coding AGM vs. non-AGM is important.

What I thought. Just wish there was a way to know AGM or not without having to pay the man. Thanks again.

There is.

Haven't checked my Carly for BMW iPhone App, but it can change battery types. I don't know if you can "read" how the car is currently programmed. That would be the best route if it does.

There is a procedure using the OBD cable and BMW Tools. It looks painful (see page 4), but here it is:

I can confirm the Carly for BMW, IOS app will show all battery registration/codeings and Ah applied coming forward from build date. Don't forget you need to set your Ah setting as well if that changes with battery exchange. In most cases when you go from a FLA battery to AGM, your Ah usually goes down.

Embarrassed to say that I have been driving BMWs (and trying to do my own work on them as much as I can) for the last 15 years. We currently have three BMW cars and even a BMW moto in the family, and this is the first I have heard of Carly. Just bought their reader and will buy the app this weekend. Another valuable tool; thank you both for the heads up. Glad I inquired.

Glad to help and good luck, Keep us posted.

Would add that Carly also has a app for BMW bikes, although I have not used it.

I have a '08 535i. About 1 year ago, I replaced the OEM wet-cell battery with the same spec AGM battery. Took it to the indy, he registered it, and was going to code the change from wet-cell to AGM. He came back and told me that the existing software in the car didn't have AGM as an option, and that I must update to a newer software version ($260) in order for the AGM coding to be done....I declined. He said that the AGM might have a shortened life if left as is...but he didn't REALLY know for sure what impact it would have...if any. So, I have a registered AGM in my car that is coded for a wet-cell...no issues so far.

+1 - For $260 you could buy two or three FLA batteries if your AGM dies.

The real danger is if the AGM battery runs down in charge and the DME (through the VR) sets the system voltage to higher than 14.8V, which is detrimental to AGM batteries. The IBS is designed to monitor acid temperature and while AGMs are designed such that once 100degF is reached accelerated charging is reduced, FLA can go to 120degF.

The good thing is that your ambient temperature is not very low in Alabama so battery temperatures will tend to stay higher, which will reduce the time the system voltage is set higher if the battery charge is low..

Probably the best thing you could do would be to invest in a good quality computer controlled battery tender ($40-$50), and pop the charger on once per week (more often if you make a lot of short trips). Keeping the battery SoC topped off will prevent the DME from cranking up the system voltage, passing 14.8V, and endangering the battery.

Two things kill batteries quickly: 1.Sitting for an extended time at less than a full charge 2.Overcharging the battery.