okay, i have this jdm sweet bel radar detector, and its always beeping at me low voltage,

i put it on the voltmeter ( a built in feature, and the voltage is up and down from 9.99v to 12 v

usually when idling its at about 10.5 when im in vtec at about 7 grand its at like 12 volts and then if i hit a speed bump it drops again...

in my girls eclipse it never beeps low voltage and it a steady 13 volts at all times.

any ideas? i just changed the plug wires and it seemed to help a bit, the battery is 6 months old.

 

Maybe your Alternator is messed up.

 

i thought about that but i dont have any problems starting the car, and the battery doesnt seem to lose its charge at all.

 

it has to be your alternator. get it checked under load at a shop to verify its your problem.

 

How are you powering the detector? Direct wire or cigarette lighter plug? Might have a crappy or corroded contact.

 

cigarette lighter,
i thought about that too, but it works, and if im just sitting idle you can watch it fluctuate, so i dont think thats it.