The safest way to recharge hobby grade lipo batteries is to always use a balance charge mode.

You can ask at your hobby shop but I believe the new traxxas batteries and traxxas charge are made to balance charge.

In my years in the Rc car hobby I had witnessed a few lipo batteries go up. One was user error, charging. The others were punctured lipo packs (Rc lipos did not have hard cases back in the day).

Just a suggestion if there is a RC race track near you stop and talk to racers. They generally are willing to answer questions.

It’s fun to race with your son at a track. My son, grandson, have raced with me. Great grandson is learning to drive now.