This is the label on the top of my BMW 535d battery. Any idea what the difference is between the "A:" & "S:" numbers?
BMW battery label
- Thread starter wavinwayne
- Start date
Looks like a BMW part numbers. Perhaps it is notating new part no for one which was replaced.
What I mean is what is the difference between the AW & S numbers? They both look like part numbers.
Supposedly, it's to ensure that the car’s onboard computer recognizes the new battery and optimizes the charging system accordingly.
I edited my comment. New vs old pn. I bet one is no longer available.
That's correct, but a lot of people - primarily those that don't and have never owned a BMW - always feel the need to point this out.Supposedly, it's to ensure that the car’s onboard computer recognizes the new battery and optimizes the charging system accordingly.
It does seem excessive, but it also seems to help the batteries last longer. The original battery in my E90 lasted either 9 or 10 years, so that's a pretty good run.
There's a charging algorithm which adjusts based on the age and type of the battery. The older the battery the greater the charge from the alternator.
I'll be replacing my battery soonish I assume. The date code on the negative terminal says 50/15 which seems to indicate it's approx 8 years old. I'll be using Bimmerlink to register the new battery which I'll probably get from the local BMW dealer.
f355spider
$50 Site Donor 2024
My concern is I am an outlier. I have an almost six year old M550iX that has less than 15,000 miles and both factory AGM BMW batteries are constantly on a Battery Minder battery tender when parked in my garage. Both batteries load test "as new"...so is the IBS (intelligent battery sensor) just assuming since the batteries are 6 years old to charge them accordingly like a typical battery that gets zero care and never seen a battery tender? If so, I suspect they are getting overcharged when I am driving around.
I've been tempted to reset the IBS for a new battery installed, but so far, have just left it alone.
The IBS won't overcharge, I still have the factory battery on my 2015 (2014 build date) and although it has been on a maintainer since COVID it has aged to the point that my blend doors loose their calibrated state.
"IBS MEASURING/EVALUATION FUNCTION
The measuring/evaluation function of the IBS electronics, continuously measures the following values under all vehicle operating conditions:
Voltage (6V to 16.5V)
Current (200A to +200A)
Closed Circuit Current (0A to 10A)
Starting Current (0A to 1000A)
Temperature (-40C to 105C)
When the vehicle is stationary, the IBS is programmed to wake up every 14 sec. and makes the required measurements within approx. 50 ms in order to save power. The measured values from the IBS are provided to the DME by way of the Binary Serial Data Interface (BSD) to calculate the State of Charge and State of Health for the battery.
State of Charge (SoC) is a calculated condition showing the current charge of the battery. SoC is used during key ?OFF? periods to insure the battery maintains a sufficient charge to start the engine at least one more time.
State of Health (SoH) tracks the history of the battery. Charge/dis-charge cycles and times are monitored. SoH helps the DME determine the proper charging rates and anticipated battery life. Internal resistance of the battery is calculated by the IBS from the current and voltage dip during engine start. The values are forwarded to the DME to calculate the SoH of the battery.
Software contained in the microprocessor of the IBS utilizes the measured values to calculate the State of Charge (SoC) of the battery during vehicle sleep mode and compares this information with that received from the DME/ECM pertaining to the battery SoC/SoH, during the period of time between engine ?OFF? and deactivation of the DME main relay.
The current SoC/battery data is stored in the IBS every 2 hours over a 6 hour time frame, providing 3-2 hour snapshots of battery SoC information. The stored information/snap-shot data is overwritten every 6 hours. Whenever KL15 is activated the IBS updates the DME with the current closed circuit histogram/battery status information, by way of the BSD. Upon obtaining updated information the DME evaluates the new data and if a closed-circuit current draw is identified a fault will be stored in the fault memory of the DME."
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Just doing some quick research -
AW seems to be a part# universally recognized across the globe and the number never changes.
S are market specific numbers that regularly get superseded.
ex: your battery sold in Brazil
Poland:
Germany:
Thanks, 007. Interesting info.
The Bimmer batteries are always oversized and more of industrial tge last few I saw at local car meets. And many Bimmers have 2 batteries even for the 3 series.
But I am not sure any other makers require battery registration to even turn the car on. Many people got stranded after being lucky enough to find the right batter my size but the cars won’t start. Some was smart enough to find a YT solution if disconnecting a green connector to bypass.
f355spider
$50 Site Donor 2024
The BMW battery registration process is only required in order to reset the battery charging parameters back to zero, or new.
If you do not register the battery, the car will still start and run just fine, the issue is the charging profile in the IBS (Intelligent Battery Sensor) will assume it is an older battery and likely over charge it...which will shorten the life.
My M550iX has two batteries, my understanding of the system is the larger starting battery is in the trunk and the auxillary battery is in the engine compartment. This smaller auxillary battery runs all the electrical functions (HVAC, radio, headlights, etc) when the engine is off when using the "stop/start" function. That way, no matter how long you are stopped at a light, the car will restart off the main battery.
Bimmer got it right with 2 battery setup. I only wish Honda and Toyota follows. I am trying to figure out how to run the battery cables back to the trunk of the Fit so I can use 29DC, which is over 3 times the size of 151R for 55% less cost and available almost everywhere unlike 151R, which may only be available online. The Jazz is still spec’ed for 51R but somehow Honda USA had to use different mounting platform that has 2 protruding brackets limiting the battery size to 151R. Same goes for the tires, they cost more than much bigger tires of the same rating because of the odd size. My current set is Michelin Defender (not sure if it is II or LTX) and Costco didn’t have it for over 18 months and I had to special order when Discount Tire opened a shop locally. I would have preferred buying tires at Costco because I don’t need appointment, receipt, or mileage count to do oration and balance. And I can do that while shopping at the stores 7 days a week.
I do like the services received at Discount Tires when I purchased the set. Unfortunately, they don’t have alignment service and I’ll find out how great they are once I get the rotation and balancing.
I do like the services received at Discount Tires when I purchased the set. Unfortunately, they don’t have alignment service and I’ll find out how great they are once I get the rotation and balancing.
JHZR2
Staff member
Lois like every bmw part number I’ve seen. I suspect the situation above with global and local part numbers is right.
