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Discussion Starter · #1 ·
I need to get myself a new battery shortly and just wanted to see what people recommend for a car that will mostly only be used on weekends. I know the factory battery was an AGM but I hear these are not good if the car only sees occasional use, and are better suited to daily drivers. Is this correct? Are there any drawbacks of not going for an AGM with the M5/M6?

The current battery is just a normal lead acid which the previous owner installed so I'm guessing I'll have to do some messing around in ISTA if I go for a different sort of battery?

Best two options I've found locally are a YUASA ISS Active AGM or a Varta Silver Dynamic flooded battery.
 

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I used a non AGM, had a warranty for 3 years, and dead in 2y9mo. I suspect bad battery quality(It was cheap too, compared to its AGM counterpart, by nearly $40).
I see the same behavior with AGM on my car now compared to what I observed with the flooded battery, nearly in every way.
AGMs have the technical advantage; but someone has to prove to me its worth that extra $40 we pay.
My battery thread: 2008 m5, 141K miles, BATTERY VOLTAGE.
 

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2009 BMW E63 M6, Sapphire Black
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My M6 may not see action for a month or more. Battery always is reliable. BMW factory. My firebird, has old school battery from Autozone, same deal, fires up everytime. My 545 may not see action for a week or two - AGM from Autozone, made in Germany.
 

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Discussion Starter · #6 ·
AGM sounds like the way to go then. I was just afraid to may die quickly if the car isn't being used frequently but sounds like that won't be an issue.

Just to verify that my voltage regulator is operating correctly I might drop into the 'secret menu' whilst driving and check the voltages are stable. Don't want to fry the new battery with a dodgy regulator which seems to be a common failure point on these cars.
 

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I also use the Advance Auto part. Same thing as an Autozone battery H8-AGM is the part number. Think it was ~92 amp*hr battery.
 

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2009 BMW E63 M6, Sapphire Black
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AGM sounds like the way to go then. I was just afraid to may die quickly if the car isn't being used frequently but sounds like that won't be an issue.

Just to verify that my voltage regulator is operating correctly I might drop into the 'secret menu' whilst driving and check the voltages are stable. Don't want to fry the new battery with a dodgy regulator which seems to be a common failure point on these cars.
Some have problems with parasitic drain while the car sits. If you have that, and car sits a long time, it wont matter what you have, gotta find the source. Others may simply have old batts, or charging that is on the brink, or some other issue that is causing the battery not to fully charge or drain while sitting. So there is always that out there in the crappy batt reports you may hear.
 

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AGM batteries are much better at having charge consumed and re-added (power cycles) then standard lead-acid batteries, it causes less wear on the unit and charge capacity. If you do switch from lead-acid to AGM remember you'll not only have to register the new battery but also code the new battery type using NCSExpert or ISTA-P so the car charges and maintains it properly.

Like @specialized2010 I'm using the premium Die-Hard AGMs in both the M5 and our E70 (95ah), of all things out there batteries definitely DO NOT need to be "OE or nothing" - this is ancient technology when you think about it (until we get into lithium and supercaps being used in hybrid power-units).
 

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2009 BMW E63 M6, Sapphire Black
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I have a hunch that BMW also balanced the rear end of the car to account for the weight of the full sized AGM. Stereo AMP on left, battery on right, ect.
 

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Stereo AMP on left, battery on right, ect.
My battery is dead center and as far back as possible, did this change between years? I will say when switching I created shims for either side of the battery to lock it in place as it was sized slightly smaller than the lead-acid BMW specced back in 05'
 

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No idea, '04 E60 is in trunk, behind right side wheel well. crammed in there pretty tight. '09 E63, in center, rear of trunk
 

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8.5 years on the current AGM BMW battery for my E63... I do keep a charger on it over the winter months but I can't believe it's still going. Have to check the date sticker on it because it wasn't new when I bought the car either!
 

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Discussion Starter · #16 ·
Is there a way you can check in ISTA or INPA what type of battery is coded to the car and the registration status etc?
 

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Is there a way you can check in ISTA or INPA what type of battery is coded to the car and the registration status etc?
I like NCSExpert for this process, once you have the FWS_PSW file you can see what's currently coded in and you'll be in the position to update if necessary. I used ISTA-P for my most recent battery out of curiosity as I'd never used the software before. It's a very slow process (1 hour to get through everything) but is fool-proof, writes the VO and corrects anything else it sees wrong with your infrastructure. But don't try it unless you have a power-supply.

Below steps were copied from: https://www.e90post.com/forums/showthread.php?t=1338302

Overview:
This method is a bit incomplete in regard to coding. It uses NCSexpert to edit the settings in the CAS and NFRM modules. Essentially, you are manually changing the settings in the CAS/NFRM module to reflect the new battery.

*****While this method seems like a straightforward way to code for battery changes, it fails to address the issue of vehicle order (VO). This could have implications for future coding and ZB updates. See option 5.

*****After completing this coding, you must still perform "Option 3" to register the new battery using Tool32. Or, you can use ISTA-D to do the registering, but then you might as well also use ISTA to do the programming at that point...

Steps:
1) Load NCSExper.exe
2) Select a profile that has manipulation enabled: File>load profile> “CNCcoding”
3) Select: F1>F3>select your chassis>select “CAS
4) Press F6 for back
5) Press F4 to select a specific module “Process ecu” then you get a list of all modules available for your car
6) Select “CAS” then select “READ ECU” this is going to read all the values from the specific module and create an FSW_PSW.TRC file with the values
8) Leave NCSExper.exe open and navigate to the “work” folder ([X]:\NCSEXPER_64\WORK)

The FSW_PSW.TRC file we generated when we “read” the CAS module is where we are going to change the battery settings. After making our changes, we will then change the file extension to the file type NCS uses to write to the selected module (.MAN).

At this point, you can also use a program called NCSDummy to make things easier. You can use NCSDummy to import the .TRC file. NCSDummy will provide translations and descriptions for all the settings in the CAS module. I will not cover the details on how to use NCSDummy, it is very easy if you search. The following steps continue with how you can just simply edit the .TRC file in notepad to achieve our goal of coding a new battery:

9) Open the generated FSW_PSW.TRC file with notepad
10) Select: File>save as>FSW_PSW.MAN (be sure to select “save as type” to all files so that it will accept the “.MAN” extension. If you fail to do so it will just save it as a text file .TXT)
11) Search for the option “KLASSE_BATTERIE” and change the value from its current setting to a setting that most closely matches the rating of your new battery (e.g. “90ah” to “70ah” or if using an AGM battery “70ah_agm”) (see Appendix E)
12) Select: File >Save
13) Back to NCS now hit F5 for basic functions
14) Select “coapiReadSgGetFswPsw” and then “ok.” You are basically telling NCS to read all the values from your .MAN file. You will see a screen… just press ok. Then press ok again.

Ok now take a look where it says “JOBNAME = CODIERDATEN_LESEN” We need to change that to a coding function because we want to write the changes to the module, not READ as we did earlier.

15) Select F2 “job”
16) Select SG_CODIEREN and press ok
17) Then press F3 to execute the job. After a pause you will see the “coding ended” message!

I am not sure if these steps are 100% what you’ll see. It’s been a while since I coded my battery, but I’ll update the steps as needed.

The battery rating should now be updated in the system. You can verify the coding was successful by performing the steps outlined in Appendix D.
 

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Get a float charger - CTEk or NOCO make nice ones, and either old style or AGM will last longer. My one caveat is to not mix styles If you have a dual battery setup. They have different charge rates, and that made it harder on the 750 charging system. Alternator died. On my Yukon, I get 6 or 7 years out of an AGM -
 

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ahh, the good old battery debate! Personaly i upgraded to a 105Ah AGM from autozone (made in Germany) and recoded the car for it. Also use a Deltran battery tender regularly which will extend the battey life considerably. The battery is physically larger, H9 versus the stock H8 but fits fine when you remove the spacer and i like having the extra power :cool:
 

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I support this 👇... From a simple google summary: "which battery is better lead acid vs agm"


"AGM batteries generally last longer than standard lead acid batteries. Because of their low self-discharge rate, AGM batteries also last longer than their flooded counterparts when not in use. A well-maintained AGM can last up to 7 years, while flooded batteries typically last around 3-5 years."


$229 for AGM vs $189 for lead acid. My lead acid died in 2yr 9mo. Lets see how long my AGM lasts now.
 
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