Bimmerfest BMW banner

1 - 17 of 17 Posts

·
Registered
Joined
·
113 Posts
Discussion Starter #1
My 2015 35d has 2 batteries, one is larger than the second battery. The larger one is on the drivers side rear, the smaller one on the pass side rear. The larger one I think is the starting battery, not sure the second one I have no idea what it does. The larger one for replacement would be a BMW battery, or Exide MX-H8L549, the smaller 50 AH battery appears to be a european only and I have no idea what would be a replacement for it, also both of the BMW batteries have vent hoses connected to them, I think the Exide does also. The other thing is the smaller battery part number S:61 217 623 131 looks like it has been replaced with a new part number, this is very confusing, like just visit your local BMW Dealer, and that I care to avoid, so anybody know what works for the smaller battery??
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
Joined
·
17,072 Posts

·
Registered
Joined
·
971 Posts
My 2015 35d has 2 batteries, one is larger than the second battery. The larger one is on the drivers side rear, the smaller one on the pass side rear. The larger one I think is the starting battery, not sure the second one I have no idea what it does. The larger one for replacement would be a BMW battery, or Exide MX-H8L549, the smaller 50 AH battery appears to be a european only and I have no idea what would be a replacement for it, also both of the BMW batteries have vent hoses connected to them, I think the Exide does also. The other thing is the smaller battery part number S:61 217 623 131 looks like it has been replaced with a new part number, this is very confusing, like just visit your local BMW Dealer, and that I care to avoid, so anybody know what works for the smaller battery??
@RonD68....following this post. I too looking for a nondealer solution for this 2nd battery. It's my understanding this is because of the optional equipment u have; ie rear heated seats, entertainment etc. Wondering if u could put a 95ah single battery to replace the smaller one.

Sent from my SM-G930R4 using Tapatalk
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
Joined
·
17,072 Posts
@RonD68....following this post. I too looking for a nondealer solution for this 2nd battery. It's my understanding this is because of the optional equipment u have; ie rear heated seats, entertainment etc. Wondering if u could put a 95ah single battery to replace the smaller one.
No. The batteries and their loads are separated by the Power Control Unit.

https://www.newtis.info/tisv2/a/en/...system/power-distribution-box-rear/1VnXCCKLeJ

It is pathetic that these high tech automobiles are treated as though they are ‘57 Chevvies.
 

·
Registered
Joined
·
113 Posts
Discussion Starter #5
@RonD68....following this post. I too looking for a nondealer solution for this 2nd battery. It's my understanding this is because of the optional equipment u have; ie rear heated seats, entertainment etc. Wondering if u could put a 95ah single battery to replace the smaller one.

Sent from my SM-G930R4 using Tapatalk
I measured the existing smaller battery, the problem is there isn't room for a larger one, between both batteries is a silver electrical component, also all the BMW batteries for the X5 are listed as special size, the height appears to be the issue, 7.5 inches, most batteries are about an inch taller. Doug provided the way to locate the factory part, I did, but they won't ship any longer, so drive to the local dealer and buy looks like the only option. I work on 90% of everything on all my vehicles, this is going to go into that 10% area that let the Dealer do it, I expect 6-7 years out of the 2 batteries, so I will just pay more and let them screw with it.
 

·
Registered
Joined
·
971 Posts
I measured the existing smaller battery, the problem is there isn't room for a larger one, between both batteries is a silver electrical component, also all the BMW batteries for the X5 are listed as special size, the height appears to be the issue, 7.5 inches, most batteries are about an inch taller. Doug provided the way to locate the factory part, I did, but they won't ship any longer, so drive to the local dealer and buy looks like the only option. I work on 90% of everything on all my vehicles, this is going to go into that 10% area that let the Dealer do it, I expect 6-7 years out of the 2 batteries, so I will just pay more and let them screw with it.
RodD68.....keep me posted on what you do & cost of dealers batteries. I'm pretty sure Advanced Auto Parts sells the 90ah AGM (AutoCraft Platinum AGMBattery, Group Size H8, 900 CCA) for $200. I'm ok with that. It's the smaller one that I'm having a hard time locating (50ah) .I'm guessing that the dealership will be charging the better part of $500 for both.



Sent from my SM-G930R4 using Tapatalk
 

·
Registered
Joined
·
113 Posts
Discussion Starter #7
I am thinking both installed about $1000., and if only every 7 years thats sort of OK
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
Joined
·
17,072 Posts
I am thinking both installed about $1000., and if only every 7 years thats sort of OK
Seven years service life from batteries in a BMW would be exceptional. Count on four years.
 

·
Registered
Joined
·
1,201 Posts
Seven years service life from batteries in a BMW would be exceptional. Count on four years.
I had the original battery replaced in my 2012 X5 35d in January of this year (2019) as preventive maintenance. The original battery was showing signs of needing to be replaced. The car was built in early 2012, IIRC so I got around 7 years out of it. My highway miles kept it charged all the time. I am not the first owner but the car has seen highway miles for all of its life.



Sent from my XP8800 using Tapatalk
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
Joined
·
17,072 Posts
The first correlation of battery service life is the average State of Charge. An average SoC of 70% => 1,000 cycles of full capacity discharge - recharge throughput. With a nominal 100 AH capacity that's 100,000 AH throughput.

. <<==There***8217;s spoda be an image there

http://jgdarden.com/batteryfaq/battery_life.gif
 

·
Registered
Joined
·
113 Posts
Discussion Starter #14
Here's pic of both large & smaller battery

Sent from my SM-G930R4 using Tapatalk
I wonder if you can locate a battery same size to fit but higher AH?, I doubt it will hurt anything, I think but not sure the BMW replacement is higher AH
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 98K miles NOKIAN WR G3 12K miles
Joined
·
17,072 Posts
I wonder if you can locate a battery same size to fit but higher AH?, I doubt it will hurt anything, I think but not sure the BMW replacement is higher AH
What determines the AH capacity of a battery?
 

·
Registered
Joined
·
113 Posts
Discussion Starter #16
Use RealOEM.com to get the part number for the auxiliary ASS battery, then general purpose search engine for retailers with that part number. Batteries are commodities. The vent hoses are for AGM batteries venting to the outside.

BMW F15 X5 xDrive35d SAV
Would you know if ASS means auto-start-stop?. In other words that is all the smaller battery is for?, since I never use it maybe I don't have to worry about the smaller battery
 

·
Registered
Joined
·
12,151 Posts
Would you know if ASS means auto-start-stop?. In other words that is all the smaller battery is for?, since I never use it maybe I don't have to worry about the smaller battery
The auxiliary battery is used for additional power needs for various options or standard equipment like the EPS (electronic power steering) and IAS (integral active steering aka rear wheel steering). If you have the auxiliary battery...it is being used but it is also maintained by the PCU (power control unit).

1010892


1010893
 
1 - 17 of 17 Posts
Top