I just recently purchased a used 2008 mazda3 i touring, and I noticed that the battery was enclosed in some sort of plastic make-shift walls. One of the walls was broken, so the lid was placed in the trunk of the car. My question is this, is the cover really necessary? This (first mazda owned) is the first time I've seen a car with a battery cover, so I'm not too sure if it is actually necessary, or just something that Mazda does.

On another note, is the 2008 mazda3 i touring's audio system not that great? At higher speeds while driving, I tend to hear static-ish noises with the radio (and coincidentally ONLY the radio). Is this a fault with the antenna? On my previous vehicle, a 1998 toyota sienna, I have never run into this problem, even with a completely stock system.

 

I think there are a few people that run without it and don't have issues. I've heard it allows air to be blown on it and it is separate to keep it cooler. I don't know how accurate that is. Maybe it is just to clean up the compartment.

Yeah, that is more than likely the crudy antenna. Got to a shark fin is supposed to make it even worse. I don't know that there's much you can do.

 

If you look just in front of the battery compartment, if your vehicle still has it, there is a vent from the grill to the battery, to keep it cool.

Though I don't really think that the lid is neccessary. Or you can do what I did and make it pretty!

 

I am inclined to believe the cover has little to do with cooling (positive or negative) and much to do with protecting the battery from any spark sources that could cause it to explode. Granted batteries don't explode all that often these days (I had one go about ten years ago), but when they do they will (at the very best) make an enormous mess, and (at the very worst) cause grevious bodily harm or even death to anybody working nearby.

 

It does also keep the battery rather clean compared to the dirt crusted batteries I have had in the past.

 

you don't need it, i can't have mine on with my strut bar or i won't be able to access the battery, and you don't need that vent on either.