My lights have been dimming when I brake. I dont know what this could be, my battery is ok, although I dont know how old it is. Does this mean I need a new altenator, or should I just buy an Optima battery?

 

Mine does the same but lights getting dimmer only on couple sec.
Being checked alternator (nissan steallership) everithing is fine
stopped worrying

 

Same thing happens to me. Got my battery and alternator checked and they are fine. What can it be? Oh, maybe just a sucky battery?

 

i have the same thing...also the lights inside dim for a split sec as well. but then again i didn't check the alternator. when i was buying the car (used), i told the guy to replace the battery, so he did, but he connected it backwards, thus blowing the alt. waited a week and he said he "fixed" it.

 

Same thing happens to me. about a week ago i went to have my battery and alt checked, both were fine but i knew i had a crappy battery so i went ahead and got a red top optima battery. still does it to this day, someone did tell me that it could be a ground that may be draining some juice out of the battery but i cant find one so i have no idea what it could be.

 

Clean all your earth/ground contacts. Sounds like resistance caused by a bad earth.