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

[FooDogg]

Thanks GolfDave again for the detailed DIY., my standard 56ah battery, was its way out (3 yrs old)., with difficulty starting and occasional no enough power to start.



After researching with 70ah AGM Batteries (Interstate, Duracell and Duralast Autozone battery)., settled with the Duralast with 3yr replacement warranty one.



Fits perfectly on the craddle/base. Had a fibre/felt battery cover that did not fit (since the new duralast is bigger)., but was able to modify the sleeve (cut and reattached it to make it bigger.



Even the VCDS coding was very straight forward-

Battery Type

Battery Capacity

Serial Number.



Attached is the duralast battery model and spec, in case if someone is looking for it.

[emoji106]


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[FooDogg]

Hello,



Thanks for the DIY, OP! My battery died quite suddenly after just two years and eight months. But, it's worth noting that my electrical load is a tad higher than the average GTI owner. Also...







Thanks for sharing that. I upgraded to this AGM from Batteries+. I made a video and shared it at https://youtu.be/36OB96OtUsE.



Take Care,



Scott

[emoji106]


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[FooDogg]

I don't think that's true... Lithium ion batteries are notorious for being finicky, prone to heat damage, and when they do fail they fail explosively. A variant, lithium polymer, are common for RC cars and they require careful charging and storage. You aren't even allowed to transport them by airplane

Correct me if I am wrong but Li batteries can be damaged charging below 32 /O C, and require a trickle charge function to charge at a much lower rate.

https://relionbattery.com/blog/lithium-battery-cold-weather

I wonder if the BCM and changes to ACU by battery coding make that process happen?

Lots of places I drive routinely go far below that in winter. -30F is not uncommon never mind wind chill.



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[FooDogg]

Nice to help...& My bigger battery is still ok...…!!

PS: Thanks Dave for a very useful, info dense post. Saved for reference on my 17 AT S MT, to do an upgrade as stock parts age out/fail;

Always prefer to improve Brakes, clutch, suspension, lights, when cost-effective to increase safety and reliability, but frugally and thats when the opportunity for OEM part improvement comes to improve upon the bean counters "good enough" stock part.

That can be challenging for a noob like me to parse, technically, so this is a huge time saver to have the solution ready to go, with other wise users proven experience already ahead of my due diligence.

Saved for reference.


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[Bertroni]

I have a 2015 GTI S without stop/start and no BCM that I can see (negative terminal has no extra wires). My original battery died a few weeks ago, so I replaced it with a bigger size 48(H6) AGM battery from Carquest (brand name is Autocraft). I didn’t realize until I started swapping the battery out that it was much bigger than the original.

Should I be concerned about doing the reprogramming for the new battery? I didn’t realize that was even a thing until after I made the swap. The owners manual makes no mention of a BCM or a need to reprogram anything after a battery replacement. Warning lights turned on on the gauge cluster initially, as expected, then went away after a short drive. Trip monitor reset to zero, but other than that, all settings remained intact.

The new battery has worked great so far after a few weeks. I don’t have the tools to reprogram the computer, so hopefully it’s not necessary in the earlier US models?

 

[StealthGTI]

Do you really have "Start/Stop" on a four year old car, as in the engine turns off automatically at stop lights and then restarts when you press the gas pedal? Or are you referring to push-button start? I *think* only the true Start/Stop cars have the BCM so that the car will deactivate the feature if the BCM detects insufficient battery charge.

I may be wrong on that; haven't been able to confirm.

 

[Bertroni]

I said I did NOT have stop/start, or push-button start for that matter. Without this feature and without the BCM altogether, is it still necessary to reprogram a new battery?

 

[StealthGTI]

Oh damn!

I said I did NOT have stop/start, or push-button start for that matter.

So sorry to have misread that. You wrote in basic, clear English, too. I must've been weary from working in the heat.

Scott

 

[adonnan]

For what it's worth, I was able to reset/modify battery values with OBD Eleven.

Just go to Control Units > Gateway 19 > Adaptation > Battery adaptation.

From there you can change the battery capacity, whatever three letter manufacturer, your favorite 10 digit serial number and what battery technology it is. For our 16 golf sportwagen it was set to 60 AH and liquid. Changed for 70 AH and Binary - AGM.

 

[Vorne Au hinten Weh]

Battery Charging Voltages

AGM batteries need a higher charging voltage than the regular plate lead/acid batteries regular (non start/stop) Golfs seem to come with. May be useful to program the car so it can make the charge voltage adjustment for the AGM battery.

 

[anotero]

I'm going to be replacing my 60 Ah OEM battery with a 72 Ah OEM one. Should there be any issues doing so? I know for sure that it fits my battery tray.

 

[volmaniac]

Our 2016 GSW S teeny tiny battery failed quite suddenly as well after almost 4 yrs (3 yrs, 11 mo, 13 d). No BCM wires on the negative terminal, and the VCDS coding seemed to take. Replacement is an Advance H6 AGM battery. Thanks to the OP and all the other helpful info in the tread!

 

[golfdave]

Our 2016 GSW S teeny tiny battery failed quite suddenly as well after almost 4 yrs (3 yrs, 11 mo, 13 d). No BCM wires on the negative terminal, and the VCDS coding seemed to take. Replacement is an Advance H6 AGM battery. Thanks to the OP and all the other helpful info in the tread!

That's less than 3yrs..christ!!...

My bigger AGM is still going strong....5yrs in Jan 2020...

 

[volmaniac]

We got the car November 1, 2015... so almost 4 years. But when it died, it died without hardly any warning.

Good to hear on the AGM life! I have been using AGM on the 02 TDI for about 5 years too! Cheers!

 

[jimlloyd40]

That's less than 3yrs..christ!!...

My bigger AGM is still going strong....5yrs in Jan 2020...

Battery life depends upon how hot it gets where you live. In Phoenix 2 to 3 years is all a battery is going to last.