3 years old and need a battery...
Hi Folks. Our 2012 Golf just celebrated her third birthday yesterday. I just serviced the battery and the hydrometer was borderline between FAIR and GOOD. Water levels were OK. Resting voltage around 12.6 (out of the car). Charged overnight and load tested. Came up with WEAK on the tester. Charged again, installed in the car and measured voltage while starting the engine. 9 volts. OH OH!
So, I went on a quest to find a battery that would hopefully last longer than three years.
The MK VI TDI is tough on batteries. I'm fully convinced that the excessive engine bay heat (more than likely from the regens) combined with high amperage loads from the cooling fans / electronics when the engine is turned off aren't helping. Regens always seem to happen when we are parking the car, even though the car just had a one hour commute. Go figure.
Anyway, I decided to go with an AGM (absorbent glass mat) battery. They can take the heat, leak proof, they are truly sealed, they charge up to 5 times quicker, discharge at a much slower rate than flooded batteries, and can also take a lot of vibration. They also typically last longer than flooded batteries. I use AGM batteries in my motorcycle with excellent success and standby generator.
My cost options were $146 CDN at my VW dealer for a VW OEM replacement (Interstate); $250 for an Interstate Mega-Tron Plus; or pay a little more for an AGM. I was unable to get a price on the Interstate MT7-48/H6 from Interstate dealers here, but MSRP is about $360 CDN.
Upon researching this, I wanted the Varta Silver Dynamic AGM that has 760 CCA, and 70 Ah. It weighs 44.8 lbs. It is a direct fit with an H6 case size. Not available in Canada. The original Varta in the car had 640 CCA and 72 Ah. Weighed in at 42.5 lbs on the scale.
Contacted the local Mercedes dealership and their replacements are Varta's with the Mercedes label on top. Made in Germany.
I picked up a Mercedes (A 004 541 86 01) Varta AGM for $286 CDN. It was listed at $318. Two years free replacement, years 3 and 4 are pro-rated at 50% (in Canada, anyway).
I'm pleased with my purchase. I'm not pleased in having to replace a battery in only 3 years. So, with the various warranties being offered, VW was the worst with 1 year free replacement and I believe 4 years pro-rated. Interstate had 30 month free replacement and then 45%,25%, 10%). The MT7 AGM had 4 years free replacement. Besides, I didn't want to change the battery in 3 years again. I really wanted to have a battery that would last more than 3 years in this car. My previous car (2004 Jetta Wagon TDI) had the battery changed after 8 years, and that was just to make me feel good. It still tested OK.
So, will this battery last more than 3 years? Who knows, but by my math it seems like it makes sense to go this route.
YMMV.
H.