Battery questions for a 2015.

GTSLOW · Apr 3, 2020

So my battery has kicked the bucket. Currently has your typical H6 lead acid battery.

1) can I install an H7 or H8 battery?

2) can I install an AGM battery.

I've heard the 2015s need a new battery tray to fit anything bigger than a H6. Also do I need VCDS if I swap to a AGM battery?

Thanks!

jjblbi · Apr 4, 2020

I can't speak directly to 2015s, check out this thread. For me dealer sourced was the solution.

Dealership Passat Battery Install

abishoff · Apr 4, 2020

You don’t need vcds to switch to agm. I installed a larger battery, non-agm from Walmart. It didn’t fit perfectly in the tray but i was still able to secure it to the existing tray.

Sent from my iPhone using Tapatalk

BKmetz · Apr 5, 2020

GTSLOW said:
So my battery has kicked the bucket. Currently has your typical H6 lead acid battery.

1) can I install an H7 or H8 battery?

2) can I install an AGM battery.

I've heard the 2015s need a new battery tray to fit anything bigger than a H6. Also do I need VCDS if I swap to a AGM battery? Thanks!

1. Yes, with a H8 you will have to modify the battery tray and airbox. Not sure with a H7. You're right about the battery tray. It is sized for a H6. AFAIK, there is no drop in battery tray for a H8. Here's a thread on what it takes to install a H8 in a NMS Passat. http://forums.tdiclub.com/showthread.php?t=496064

2. Yes. A H6 AGM is a direct drop in. One should use VCDS to set the AGM setting. It changes the charging rate slightly. I don't know the exact details. A H8 AGM will need the same mods as in the link above.

As an aside, the H8 is standard in the VR6 Passats, but it is mounted in the trunk. A photo of a H8 in a Passat.

The VW stock battery is a well made battery and the H6 size gets the job done. In the winter of 2019 when we had that famous -30F cold snap, my car always started right up. Pre-glow time was always less than 5 seconds. My recent thread on getting my battery replaced. http://forums.tdiclub.com/showthread.php?t=504075

Jetta_Pilot · Apr 5, 2020

Unless I'm wrong the OP did NOT post in the correct forum thread since this thread is for the PASSAT ! He lists an 04 Golf and a 15 GSW !

As an aside I installed a H8 AGM battery in my Passat and had to modify the tray quite a bit but not the airbox! You also need to use a VCDS to change the battery type to AGM from lead acid.

jaberoo · Apr 5, 2020

On the subject of battery replacement: After not driving the car for a few days, the battery was too weak to start the car. I wondered if I had left the "ignition" on and there was a 'parasitic' leak. I charged the battery and then drove for an hour. At the terminals, I measured 14.1 V while idling, 12.4V immediately after shutting off, and 11.9V 18h later. Does this look as though the battery is discharging or otherwise failing?
In this time of isolating and distancing, I don't want to go to a dealer unless necessary. I could get an H6 delivered, I imagine. The Interstate recommended battery looks higher than the OEM.
Thanks for any advice.

VernK · Apr 5, 2020

That does sound like the battery is near the end of its life.

Yours
Vern

Lightflyer1 · Apr 5, 2020

I just went through this with my Beetle. Swapped in a stock battery at the dealer. They were not busy and almost no one there. Used the shuttle to get home and back. Took people one by one. I had no issues and they and I had hand sanitizer and I have gloves. Just touch as little as possible and stay away from others. There were only two others there when I went.

Quincy · Apr 5, 2020

This gets me thinking, since I have the original battery in my 2015. I've never had a problem, but I just joined the gazillion recently unemployed. I'm not driving to work, so why insure it? She's under a cover in the garage now, for at least a month.

Should I put a charger on her every so often, or should I get the battery that I'm bound to need any day. My 07 Dodge that I left insured didn't get replacements until it was 13 years old. Really, that was just because it failed to start after sitting for 4 months.

Lightflyer1 · Apr 6, 2020

At the least I would remove the battery and put it on a trickle charger with float mode. Batteries hate going dead and shortens their life greatly. I would reconsider dropping insurance especially if you have a loan on it. I just had to replace the battery on my 2015 Beetle.

Jetta_Pilot · Apr 6, 2020

It'll be interesting to see this afternoon. Came back from Mexico and just finishing 14 days of self isolation. Temps in the last two weeks near freezing point and had not started the car once since coming back. Hopefully my Autozone Duralast H8 AGM battery still has lots of ooomph to start the car.

Jetta_Pilot · Apr 6, 2020

Lightflyer1 said:
At the least I would remove the battery and put it on a trickle charger with float mode. Batteries hate going dead and shortens their life greatly. I would reconsider dropping insurance especially if you have a loan on it. I just had to replace the battery on my 2015 Beetle.

Personally my advice would be to just connect a trickle charger WITHOUT removing the battery from the car! Why remove it???
Certain items in the car still require to be powered.

Quincy · Apr 6, 2020

Lightflyer1 said:
At the least I would remove the battery and put it on a trickle charger with float mode. Batteries hate going dead and shortens their life greatly. I would reconsider dropping insurance especially if you have a loan on it. I just had to replace the battery on my 2015 Beetle.

I don't need to insure something I'm not going to drive. I missed out on irrational ammunition and toilet paper hoarding. The most irrational thing I could come up with was paying off my 2.9% car loan. At least while I'm hunkered down, I am certain there's nothing here that anyone would have any possible legal reason to be taking. There's also the fact that I couldn't choose to drop the insurance on on a car with a loan. I'd rather be in the truck if the zombies come.

I guess I'll just put the charger on it for a few days every couple weeks.

GTSLOW · Apr 6, 2020

BKmetz said:
1. Yes, with a H8 you will have to modify the battery tray and airbox. Not sure with a H7. You're right about the battery tray. It is sized for a H6. AFAIK, there is no drop in battery tray for a H8. Here's a thread on what it takes to install a H8 in a NMS Passat. http://forums.tdiclub.com/showthread.php?t=496064

2. Yes. A H6 AGM is a direct drop in. One should use VCDS to set the AGM setting. It changes the charging rate slightly. I don't know the exact details. A H8 AGM will need the same mods as in the link above.

As an aside, the H8 is standard in the VR6 Passats, but it is mounted in the trunk. A photo of a H8 in a Passat.

The VW stock battery is a well made battery and the H6 size gets the job done. In the winter of 2019 when we had that famous -30F cold snap, my car always started right up. Pre-glow time was always less than 5 seconds. My recent thread on getting my battery replaced. http://forums.tdiclub.com/showthread.php?t=504075

Dang my fears have been confirmed. Now to look for someone with VCDS in Kentucky. I really want that rear battery mount! :O

Jetta_Pilot said:
Unless I'm wrong the OP did NOT post in the correct forum thread since this thread is for the PASSAT ! He lists an 04 Golf and a 15 GSW !

As an aside I installed a H8 AGM battery in my Passat and had to modify the tray quite a bit but not the airbox! You also need to use a VCDS to change the battery type to AGM from lead acid.

I've had MANY TDI's over the past ten years. I just sold my 2012 Jetta to my uncle and picked up a 2015 Passat. It took months to finally find a reasonably priced Passat with the 6MT. VW crushed all the 2012-2014 with the 6MT.

GTSLOW · Apr 6, 2020

Can I see the battery type with VCDS-Lite?

Brandotonic · Apr 7, 2020

Rather than opening a new thread on the fourm I thought it best to post here. Please correct me if I am out of place, please.

My brother recently gave me a 2015 Passat TDI SaeL Premium amd I drove it two days ago and when I came outside today it was dead. The keys did not unlock the door ( it was already unlocked) and no lights or anything turned on.

1. Should I take the battery to Autozone for charging and

2. How do I properly shut the car down so I do not kill the battery?

Thank you in advance!

Lightflyer1 · Apr 7, 2020

The battery should be fully charged if possible using a wall charger. Alternators aren't meant for this task. It is very hard on them to have to fully charge a battery. Buy a charger and do it yourself or take it out and have it fully charged somewhere.

Turn everything off and put it in park and then push the button to stop the engine. Lock the car after exiting. Nothing else needs to be done.

Brandotonic · Apr 8, 2020

@Lightflyer1 Thank you for taking your time and replaying. I was not sure how to properly shut the vehicle down as this is my first keyless car.
Quick follow up: Is it normal for the TDi Passat to have the engine fans run after I put the car in park, turn off the lights, get out and lock the car???
Much appreciated!

Lightflyer1 · Apr 8, 2020

It is probably in regen mode when that happens. Read up on that here as it is important to let it finish a regen, either before shutting it off or the next time you drive it. There are tools to see when this is happening or listen to the engine to see (revs slightly higher at idle). Please read up on this though. If you are close to the Austin area I can show you some tools you can use. If you can't find anything let me know and I will post you some links.

Quincy · Apr 10, 2020

Brandotonic said:
@Lightflyer1 Thank you for taking your time and replaying. I was not sure how to properly shut the vehicle down as this is my first keyless car.
Quick follow up: Is it normal for the TDi Passat to have the engine fans run after I put the car in park, turn off the lights, get out and lock the car???
Much appreciated!

This is my first keyless car too. I didn't even know I had keyless entry until the car kept locking and unlocking the first time I washed it. I know to leave the key in the house when I wash it now.

Hopefully you have an owner's manual. I'd read it all the way through, then put it back in the glove box. I still reference it on occasion to figure out things that happen or what new lights mean. I recently found out my car has a gizmo that tells me when a tire has lost air pressure. You may very well have every option listed in the book.

Battery questions for a 2015.

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