Not 5.0 but My Mercedes keeps dieing!

[jstang209]

im not to familar with working on benz's but my 300e died twice yesterday while driving, it starts right back up tho. Im thinking it could be the alt. becuase i have 2 15's and a tv in there, all my speakers are prolly pushing around 4000watts put together. So do u think it can be a battery/alt problem? Althought it didnt seem like the lights were dim or anything like a usualy battery problem does.. I dont no where to look first. Any ideas? thanks in advance