I like to use my car stereo to play music while I'm cleaning my Jeep's interior. I also like to use my car stereo to play music for parties and random hang outs.

What is the best/safest way to keep the battery charged using main power? Also, is it safe to use the electric accessories while charging the battery?

A friend told me a smart battery charger, but there are so many different types. Can anyone suggest a good one for my intended purpose? I'd also like it to be something portable that way I could take it with me. The Jeep is only a month old and I don't want to damage anything.

Thanks,
-Trevor