Haven’t ever been able to figure this out. When am I visible to opposing players on the minimap and what can I do to not be?
When you are marked or use an unsurpressed weapon
what about when I sprint?
Nope, just anything with a weapon, grenades, shotgun etc although I don’t think knifing makes you visible
does firing a suppressed weapon show my position at all or just reduce the amount of time I’m visible?
I may be mistaken, but I think he’s asking if there is an indicator telling him that he’s been spotted. I believe the answer to that question is a simple no 
no, not an indicator, just want to know when players become visible on the minimap in general.
it doesnt show you on the map. Basically anything that makes a sound will make you appear on the minimap
-
Spotted
-
Firing an unsuppressed weapon
-
Being shot at
Really good question.
When spotted and unsupressed weapons are pretty obvious, but grenades? Those motion-sensorballs? really? Lock-on launchers? regular launchers?
And how about the battlepacks flash hider?
“Eliminates the flash generated by firing the weapon without the bullet speed penalty of a full-fledged silencer.”
Does it also removes you from the map or is it only a visual change?
On hardcore this does little change, but in vanilla it might make a difference…
I see 
Cool.
Or there is a commander and he has a UAV above you
Don’t forget motion sensors or when someone is actually looking at you whether they actually see you or not.
OR a recon throws down one of those sensor ball thingies, or a TUGs
I’ve been playing support a lot lately and finally just unlocked the c4. I’ve played engineer all of BF3 but in BF4 if my vehicle is damaged I’m bailing out and going on foot. Knifing people and blowing shit up is the best, also unloading a clip with a LMG at a group of people. They’re all dead and you just keep shooting fun stuff.
Also those dreaded UAVs and infantry scans from the enemy commander will pop you up on their team’s minimaps. You won’t show up on enemy team members’ heads up displays with the triangle from these, though.
I would like to know this.
Commander can also send out a thing that shows all infantry for a short period of time and UAVs.
Basically consider yourself always on the map. That way you wont be surprised when your sneaky feet get blasted from a random location lol.