I changed to a larger physical size 8H Duralast AGMbattery. Took a bit of work to make it fit since the AGM is about 3" longer. I had to totally remove the battery tray and modify it to fit since the tray has certain things on it which will not allow a non VAG type battery to sit flat. In...
If you're just switching over to a flooded battery there should be no reason to make any changes. When I replaced my battery and added an AGMbattery I had to set the charging for AGM using my VCDS. An AGMbattery wants a slightly lower charge rate compared to a flooded battery.
...replaced my battery with a H8 AGM Duralast Platinum battery and had to make a change in the charging. Probably the same you bought. I used my Ross-Tech VCDS and changed from a flooded battery to an AGMbattery.
A flooded battery can take a higher charge rate, the AGM prefers a lower charge rate.
A couple of years ago my Passat would not start. Bought the ONLY available set of booster cables but they could not move the starter to turn over the engine and fire up. A friend came to assist and he also had booster cables. Both sets were too small a gauge to start a Diesel.
Then I remembered...
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 AGMbattery still has lots of ooomph to start the car.
...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 AGMbattery 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...
I'm in my first week of self isolation, not allowed outside. The OEM battery died over a year ago and I put a physically larger and higher specs AGMbattery into the Passat.
Temps are from above freezing to about 40deg. It'll be interesting if I have any trouble starting the car 10 days from now?
Led acid batteries are not designed to be run down to dead. That's a battery killer!
OP done that three times, time to replace it!
Even Deep Cycle batteries should only be down to about 30%, any lower is bad for them too.
Now and in the foreseeable future I do not anticipate to be in freezing temperatures. The coldest my H8 AGMbattery has seen is about 5° C or 40°F and it cranks the engine beautifully.
Now where I spend my winters the daytime temperatures can go into the mid 90°sF or the mid 30°sC and it's nice...
When I changed my AGMbattery I lost the correct time and the then current trip meter reading and nothing else. Not worth the effort for a "memory minder".
BTW: An AGMbattery acts more like a deep cycle battery, it can be pulled down without ill effects.
I would suggest the problem is that there are too many things in todays cars which need 12volt to keep them going even when the engine is shut off.
For instance alarm systems are one.
So maybe the car manufacturer installing the least expensive barely capable battery might be at fault.
...more than is necessary, but do offer larger sizes.
Battery a size that will do the job adequately at the least cost to them. Adding an AGMbattery will add to the price of a car.. There is NO reason that you cannot upgrade to a better and larger capacity battery.
Also I am NOT talking...
...sits on had to be removed and cut/sawn to make the battery fit.
The original cables still fit.
This Autozone Duralast Platinum has much more capacity than the OEM and more CCA too.
You need to set the computer with a VCDS to AGM to allow for a different charging rate for an AGMbattery.
...sits on to make it fit. Autozone is not right saying it fits a 2015 Passat, without modification.
Set With VCDS to allow different charging for an AGMbattery.
The coldest my car sees is right now down to maybe 40 deg F. Time to leave for warmer climes!
Autozone Duralast Platinum Group 49