How to retro-fit a bigger capacity battery to a Mk7 Golf

[golfdave]

So the wire isn’t for the battery control module? It’s specifically for the stsrt stop module? That was my understanding of your original breakdown. Already been chastised on other threads for even using BCM to refer to the battery control since apparently that means Body Control Module to some people lol.

But yes either way I have no stop/stsrt module or wire coming off the negative terminal.

I’ve also quickly learned just how ridiculous it is just to change a battery on this car and have ordered an obdeleven device to do the necessary coding. Didn’t want to but I’m sure it will be handy for other stuff as well. Never had a car before where this was necessary.

I still find it hilarious though how there is no definitive answer even among this forum of whether or not it’s necessary when you don’t have the stop/start module. For every person that says it is there’s another that says it isn’t. And then you get talked to like a child because you didn’t read enough other threads that all have conflicting answers in them too (NOT talking about you specifically at all btw I truly appreciate your detailed post and responses!) Forum culture is funny like that

BUT I DIGRESS…obdeleven is on its way and the car is garaged until I receive that and can do it “properly”. Thank god for working from home and for girlfriends’ beaters

To be blunt, you can swap the batteries around & fit bigger ones & different types etc....especially on a car without the "stop/start" extra wire.....BUT the problem being the car then tries to charge the battery & read the battery amp etc for the various modules & engine requirements & it will fail...It may after some time "self-learn"...but with these cars being so damn complex it doesn't take long for them to throw a fit & light the dash up like a Christmas tree...!!!

"prevention is better than cure".....

 

[golfdave]

P.S. here is the Self Study guide pages on the basics for charging of the battery etc....this is without stop/start....

 

[AzTRgti]

To be blunt, you can swap the batteries around & fit bigger ones & different types etc....especially on a car without the "stop/start" extra wire.....BUT the problem being the car then tries to charge the battery & read the battery amp etc for the various modules & engine requirements & it will fail...It may after some time "self-learn"...but with these cars being so damn complex it doesn't take long for them to throw a fit & light the dash up like a Christmas tree...!!!

"prevention is better than cure".....

Yeah the more I read the more I’m leaning towards the “it’s probably fine but best to do it” thought process so just going to do it properly rather than risk any issues.

Thanks for the help!

 

[MADPWR]

My VW dealership said my original OEM battery that came with my 2018 Golf R failed inspection about six weeks ago when I had my oil changed. I decided to replace it now that winter is here, and this week with the cold weather my car was taking noticeably longer to start. I replaced it today with and a Costco Interstate H6 (48) AGM battery (Costco Item #1624799). My factory original battery was an EFB. I used OBDeleven to do the following battery adaptation:

-I changed the Ah from 69 to 70.
-I changed the battery type to from EFB to fleece.
-The original listed manufacturer was JCB. I don't know if the manufacturer field has significance beyond info, but I put in INT. I couldn't find an online abbreviation for Interstate Batteries.
-I changed the serial number from 1111111111 to 1120231130 (to represent today's date).

I followed HumbleMechanic's guide for clearing the codes. So, I left the windows up. I turned the car off after doing the adaptation, locked the doors, let the car sit for several minutes, came back, started the car, turned the wheel all the way to the left, turned the wheel all the way the right, but some of the warning lights stayed on. I drove it for a bit, turned the car off, turned the car back on, the last warning light (adaptive cruise control) turned off. I ran scan tool and seven faults showed. I cleared the faults, and everything looked good. I double checked that the battery information was what I changed it to at this point, and it was. However, I decided I didn't like the look of the serial number, and I changed it from 1120231130 to 0020231130. I noticed in this thread (and yes, I read all 22 pages) that there was comment about the serial number needing to be a number higher than the prior serial number. Well, 1111111111 is a higher number than 0020231130.

So, I have the following questions:

-Does the serial number need to be a higher number than the original serial number, or is it that as long as the serial number is different that is all that is needed to tell the system the battery is new? (Basically, I need to know if I should change my serial number from what I put in, or in my care changed and changed again)
-Does it matter what you write in for battery manufacturer name, or is just arbitrary information? If it matters, what should I put in for an Interstate Battery? (I did notice that HumbleMechanic used UKN to represent unknow for his Optima battery)

Also, since I saw some people having questions about the removal and installation of the battery. I have the stock air box and lidless version of the battery blanket. I did not need to remove the air box. I was able to use a wire coat hanger that I bent up to hook the bolt eye of the retention bracket to get it pulled out. I did have to move the blanket up a bit to get it of the way of the bracket. I was also able to get the new battery in with the blanket on. The bracket was tricky to get back on. I did have to have the blanket pulled up a bit, but I was able to slide the bracket down with the part of the bracket that goes towards the front of the car down first. Then I rotated the bracket downward into position. I moved the blanket back down. The blanket part facing the driver's side wheel was tricky to squeeze between the battery and the tray, but I was able do it with the tips of my fingers pushing the bottom of the blanket into place. The hanger or a real long screwdriver probably would have also worked. But if you have, or can make, the right tools, it is possibly to do the battery removal/install without removing the airbox. But, with that being said, it would be for sure easier to do the job if you remove the airbox. I do need to go back and torque the battery bracket now that I found the value of 15Nm (11lbft) was posted by golfdave. Since I followed HumbleMechanics guide, I at least torqued both battery terminals to 53 inch pounds. Also, I probably had my battery disconnected for at least an hour with no power going to the car (I decided to really clean the battery tray and blanket. I also had a hard time finding my socket extension). I did not lose any radio information or anything else from what I could tell. My clock is set for GPS time, and as soon I started the car the clock updated to the correct time). So, I wouldn't bother trying to hook up an alternate power source while swapping the battery.

Any assistance on my questions from above would be outstanding. Thank you.

 

[golfdave]

So, I have the following questions:

-Does the serial number need to be a higher number than the original serial number, or is it that as long as the serial number is different that is all that is needed to tell the system the battery is new? (Basically, I need to know if I should change my serial number from what I put in, or in my care changed and changed again)
-Does it matter what you write in for battery manufacturer name, or is just arbitrary information? If it matters, what should I put in for an Interstate Battery? (I did notice that HumbleMechanic used UKN to represent unknow for his Optima battery)

As I started this thread all the upto date info is in the first posts by myself, as I always update these...

• The serial number can be anything, just it has to to be greater in numerical value by +1 than the old one as that is what the BCM looks for to see that a new battery has been fitted....this as you can fit the exact same battery as the previous one, therefore the only difference in the coding is the "serial number".....
• Manufacturer name, write it down & the BCM will shorten it to an abbreviation....

 

[MADPWR]

Thank you for the response. I must have completely missed in my reading of this thread the part about just writing out the battery manufacturer name. I went back this morning and typed in INTERSTATE, and the system abbreviated it to INT. I also went back and changed the serial number again, but this time I just went with 1111111112. I figured at this point just do what works for others. I probably didn't need to do this next step, but I erred on the side of caution and got out of the car, locked the doors, and let the car sit for several minutes. So, hopefully I have everything right now, and hopefully the car understands it has a new battery.

I am curious, and I apologize if this was posted prior and I missed it, does the car do anything different based on what is listed for battery manufacturer?

 

[golfdave]

I am curious, and I apologize if this was posted prior and I missed it, does the car do anything different based on what is listed for battery manufacturer?

Unknown to my knowledge...others have speculated that there is a pre-loaded set of parameters for different manufactures, I don't know to be honest.....

 

[DV52]

@MADPWR: Hi.

Two points to make before answering your specific questions (common sense stuff, really)!!

First: despite ALL the advice provided in the countless posts on this thread - it's all speculation!! This is NOT a pejorative statement - it's simply a statement of fact! There ain't NO official view of these matters provided by the deities on the VW mother-ship - so whatever is being said here (yes, including my posts too) is our opinion - based on observation and individual logic!!

Second: The ability of the car's Energy Management System (EMS) to accommodate new batteries that are produced AFTER the build date of the car is very, very limited - meaning that the EMS can ONLY accommodate these batteries to the extent that they share characteristics that were known at the time when the EMS software was written into the car!

-Does the serial number need to be a higher number than the original serial number, or is it that as long as the serial number is different that is all that is needed to tell the system the battery is new? (Basically, I need to know if I should change my serial number from what I put in, or in my care changed and changed again)First

As others have said - I also don't believe that there is ANY intelligence that the EMS uses from the battery serial number - other than when it is changed.

Again from a logic perspective - it's not reasonable to believe that the EMS could be expected to "understand" (and therefore make use of) every future battery manufacturer's serial numbering system post vehicle build!

Obviously we can postulate countless theories for the purpose of the serial number in the EMS - but Occam's razor suggests that a far simpler (and therefore, more likely) explanation is that the battery serial number is a switch for resetting the previous battery history file when the number is changed!

Read my point in my answer to the next question about VW inventory allocation being a possible reason for including the actual battery serial number in the EMS

I like your date-of-installation protocol because it adds information to the serial-number entry which otherwise wouldn't exist. In engineering speak, your nomenclature increases the efficiency of the data point -well done. I hope that you don't mind if I thieve your excellent idea!!

-Does it matter what you write in for battery manufacturer name, or is just arbitrary information? If it matters, what should I put in for an Interstate Battery? (I did notice that HumbleMechanic used UKN to represent unknow for his Optima battery)

Again, the original software designers of the EMS could NOT be expected to foresee the name of every future battery manufacture - and especially since the retailer name that is plastered on the battery is often different to the actual manufacturer name.

My hunch is that the list of OEM names in the channel setting is simply those battery manufacturers that were contracted to VW at the time of vehicle construction.

If I'm correct -this entry (and the serial number entry) could have a very different purpose to the technical role that is assumed in this thread! For example: maybe this data point was meant to be some form of inventory identifier -possibly for the purpose of monitoring post-build battery longevity (perhaps for attributing warranty claims)? I'm guessing of course!

In any event and repeating my previous point, the database of known battery manufacturers in the EMS is of necessity very limited to the time that the software was written. It doesn't matter, or more correctly "it can't matter" as a technical issue if the manufacturer name of the new battery is not in the specified channel list - again, IMO.

 

[Oscar LaVista]

Thanks for all of this. My original battery died exactly like everyone says, 5 years, 5 months, 77K miles. One hard start, one start after 90 min charge, no start after overnight charge. New DieHard, stock size, no coding, on the road again.

Are the VW or non-VW replacements dying on the same schedule?

 

[MADPWR]

I found my battery tester after I swapped my battery. I just have the most basic of car battery testers, where you just enter the Cold Cranking Amps (CCA). I had to guess that it was 360 CCA, since my stickers fell off the battery several years ago, and the only pictures I could find showing an OEM battery in a Golf Mark 7.5 showed 360 CCA. My results were 303 CCA (in a 60 F degree garage), 71% SOH, 98% SOC, 8.55 milli-Ohms, and 12.63V. All of which show as good on my battery tester. I'm a bit annoyed, because now I don't know if my dealership's information about a failed battery test a couple of months ago was wrong. But, on the other hand, I noticed better battery testers have selections for battery type, CCA, terminal post location, battery in or out of car, and can even test your alternator. Also, I'm not sure how accurate the CCA result is, since CCA is a 0 F degree measurement. But, my battery was within two months of being five years old when the dealership said it failed the test. I keep the car in a heated garage, and I always have auto stop/start turned off. However, I really hope I didn't replace a good battery. It did start slow one day two weeks ago, both in the garage and after work outside. The next day it was cold too but seemed to start normally. I only have about 57,000 miles on mine.

From everything I read here and other places, you are doing yourself a disservice by not coding your battery, especially if it is AGM and your stock battery was EFB. I have a colleague who has a VW, and just the other day he said he has to replace his battery every single year. He had never heard of coding. He had an FB or an EFB, and he keeps putting AGM batteries in without coding the car to know that it is an AGM battery. I think he said he is on his third or fifth battery now. His VW is somewhere between 5-10 years old (I think 7-10 years actually), but I have never gotten up close to it.

 

[golfdave]

Thanks for all of this. My original battery died exactly like everyone says, 5 years, 5 months, 77K miles. One hard start, one start after 90 min charge, no start after overnight charge. New DieHard, stock size, no coding, on the road again.

Are the VW or non-VW replacements dying on the same schedule?

I found my battery tester after I swapped my battery. I just have the most basic of car battery testers, where you just enter the Cold Cranking Amps (CCA). I had to guess that it was 360 CCA, since my stickers fell off the battery several years ago, and the only pictures I could find showing an OEM battery in a Golf Mark 7.5 showed 360 CCA. My results were 303 CCA (in a 60 F degree garage), 71% SOH, 98% SOC, 8.55 micro-Ohms, and 12.63V. All of which show as good on my battery tester. I'm a bit annoyed, because now I don't know if my dealership's information about a failed battery test a couple of months ago was wrong. But, on the other hand, I noticed better battery testers have selections for battery type, CCA, terminal post location, battery in or out of car, and can even test your alternator. Also, I'm not sure how accurate the CCA result is, since CCA is a 0 F degree measurement. But, my battery was within two months of being five years old when the dealership said it failed the test. I keep the car in a heated garage, and I always have auto stop/start turned off. However, I really hope I didn't replace a good battery. It did start slow one day two weeks ago, both in the garage and after work outside. The next day it was cold too but seemed to start normally. I only have about 57,000 miles on mine.

From everything I read here and other places, you are doing yourself a disservice by not coding your battery, especially if it is AGM and your stock battery was EFB. I have a colleague who has a VW, and just the other day he said he has to replace his battery every single year. He had never heard of coding. He had an FB or an EFB, and he keeps putting AGM batteries in without coding the car to know that it is an AGM battery. I think he said he is on his third or fifth battery now. His VW is somewhere between 5-10 years old (I think 7-10 years actually), but I have never gotten up close to it.

I'm still on the Bosch AGM "096" case that I fitted way back in January 2015yr......Mind you my car is garaged & I have a Ctek charger that has a "AGM" function that I plug the battery into every 2 months, just to "top-it-up".....