What exactly is the function of this thing? I'm about to install some audio equipment in my 08 G35 and will be upgrading my wiring and maybe an additional battery for the rear. Does this fusable link keep the alternator from charging all the time? If so, I'm going to have problems with this. Here is a pic of what I'm talking about.

 

Yes that is the fuse for the charging system

 

Yes it is the fuse for the charging system, BUT it doesn't control the charging of the alternator or keep it from charging all the time. It just protects the electrical system. However you might run into problems trying to charge two batteries if they are both on the low side. The current could be a bit high in that scenario. You will probably be fine though. Just try it out.

 

Thanks guys. That makes me feel better. I've heard that on cars different from ours, that this fusable link did prevent their alt from charging. These people had to turn on their AC or headlights to get the thing to start charging. Their stories kind of had me worried.