I installed a Bosch group 49 AGM battery on Nov 18, 2017. this battery has a no cost replacement warranty for 4 years. On Nov 18, 2019, I went out to warm up my 06—E320, unlocked the car, went to start it and click click click. Nothing was left on. My jump pack would not start the vehicle, but it has in the past (Sept, Oct 2017) several times without an issue, there was 5 volts on the battery. Got a free replacement from PEP BOYS, they are no longer going to carry Bosch batteries, he stated too many returns on the Bosch. Pep Boys is now going to sell Champion brand, but they didn‘t carry group 49 yet. The new battery has been in one week, no problems of mysterious draining so far.