Quote:
Originally Posted by 80stech
No problem with using AGM battery on the E53. There are some pretty good threads on here about some of that, it might be interesting to check those out. I have had both my E53 and my wife's E83 switched over for a long time and they have been great. I go out of my way to use Delco batteries though and have been for more than 40 years! 
I'm not a big fan of maintainers and they are known to be hard on batteries, maybe some more or less than others, but if you can avoid them and take the draw off the battery it will for sure last longer. |
Good to know your e53 didn't have issues with an AGM battery.
I might put the charger/maintainer on the battery 2-3 times a year for a day or two. The X gets driven maybe once a week to the store, so disconnecting the battery really isn't an option with it being buried in the back of the vehicle.
Been using what's called a smart charger. The CTEK goes through an 8 level charge cycle and the NOCO Genius I just picked up does a 4 level charge cycle.
I've had a different experience with a battery maintainer. I've used the CTEK on a jetski AGM battery for 6 years now. Usually your lucky to get a couple years before needing to replace them. That battery is taken out and stored on a bench each year with the smart charger left on it. I agree, disconnecting the battery from any draw extends the life quite a bit.
I also use a smart charger on my 2 truck batteries (primary/secondary) and get about 10 years of life. Again they only get charged 2-3 times a year.