I put a brand new battery in the Volkswagen today! My first Absorbed Glass Matt (AGM) battery too! I did a whole bunch of research and found that an AGM battery would be perfect for a car that sits out in the cold, only does short trips, and completely discharges its battery occasionally.
LOL, WHAT? This guys sounds crazy, he just paid 50% extra for a battery for a car he doesn't drive and if you look at the pictures he didn't even get the right size?!?
Let me explain some more.
I had killed the Group 94R (OEM Size) battery that was in the TDI
I had a Group 47 battery (wrong size, I know, it was sold to me by an autoparts store before I knew better) but it had been abused and was very weak.
I plan on using the Volkswagen as a backup generator by connecting it to a 3000 Watt inverter. I already have had great success using this setup to power a 4.5 HP shop vac that can be used as a back up sump pump. I looked into getting the biggest possible deep cycle marine battery that would fit on the TDI's battery tray, but then I did so more research and found that and AGM automotive battery would make more sense because it is designed to provide cranking amps yet would withstand greater levels of discharge and would recharge faster than a regular flooded lead acid battery. Besides, I would not be using the inverter without the engine running so I don't need a deep cycle battery.
Still, the price of a new battery for an old car that might only get used as a backup generator didn't make sense, until, I had EUREKA moment! I could justify the price of a really nice battery if it would also fit our new Honda Odyssey! The Honda takes a Group 24F battery that is slightly undersized for the TDI but about the same size at the Group 47 battery that I was sold years ago. Here is a comparison I cut and pasted together, note how much larger the 94R battery is:
Today I went out and bought this fresh new battery for my favorite toy (Group 24F in foreground, Group 47 behind and the Group 94R was not available for this picture because it had already been returned for the $20 core charge)
There is a bunch of extra space in the battery box, space for 20 more amp hours, oh well, this is a compromise for a battery that can serve duties in our Honda at a moments notice. Another important thing is that the factory VW hold down clip actually works here:
The 24F is a bit taller than the 47 and 94R, and the plastic "fuse holder bridge" is under tension, but it is held down by its own clips:
There is room to tuck the CTEK charger down the passenger side of the battery, but for now I have just set it where I can see the eight stage charge indicator. Maybe in the future I will use the CTEK ring terminal adapter and zip tie the charger to the inside of the battery box and re-install the battery cover. For now, I just have the clamps and everything out in the open, but protected from rain and snow under the hood. I found out the hard way that CTEK chargers (and others) are "weather resistant" but not "water proof" so they need some protection.
I really enjoy just standing back and looking at the engine bay after a fun job like this, so many good times... it would be nice to clean it one day.
Almost forgot to mention, cranked the engine with the new battery and it really jumped to life. Nothing like a new battery after beating on a tired old battery for too long.