Newbie with a 2004 E4 - Best Maintenance Free Batteries?

I’m a newbie with a 2004 E4. Sorry, I haven’t found via Search feature answer to my question.

What’s the best maintenance free batteries that’s commonly available at a local store for an E4? Not interested in LiON. My GEM has an upgraded charger. I don’t know brand or anything as I haven’t dug into yet. Just got the car locally.

Thanks!

try searching for 31DCM it should get you discussions you’d be interested in.

if your looking for the best lead battery , get a set of 31 gel batteries . Agel battery will significantly out perform any other type of lead battery available . Thats why
Gem put them in your car to begin with . What upgraded charger do you have ? can it handle a gel battery ?