Replaced my battery
I've been having battery issues since the start of lockdown. As I was able to work from home it didn't bother me too much and I picked up a new battery charger. The car would be flat if left for a few weeks without driving, so I assumed one of the retrofits is causing a slow battery drain. More recently I've been driving the car every 3 or 4 days, but it still went flat, so that got me thinking my 5 year old battery may be unhealthy.
I did a bit of research on which one to get, it appears that AGM batteries can be fitted, but if your car wasn't fitted with one from factory the charge characteristics may cause issues, as AMG batteries have higher voltage peaks (So your car would require a Battery Management System or Intelligent Battery Sensor to manager them correctly) as well as requiring charging 0.3V above conventional flooded batteries. I then came across EFB, which are Enhanced Flooded Batteries and are a halfway house between Flooded and AGM batteries and can be fitted to cars that came with either from factory. I guess you'd use EFB in your start/stop car if you couldn't stretch to the price of an AGM. For people with a regular battery from factory and EFB makes a nice upgrade; better charge acceptance and typically double the duty cycle and only about 30% more expensive.
Anyhoo, I went for a Varta N70 (an 096 type for our Mk5 cars) and I'll keep you posted how it performs. It was £90 with an eBay 20% off coupon, which is the cheapest I could find and has a 4 year warranty.
I also discovered during my research that Bosch and Varta have been the same batteries for the last 7 years, the only difference being the labels they stick on them. The Varta was cheaper than the Bosch part.
Cheers
Stu
