My sweetheart has been running low on volts. The alternator regulator went out not all that long ago and was replaced but the thing still reads 11 volts at the battery during idle. It was reading 12 during day time driving and increasing with rpms to about 14 but at night with the lights on the gauge is reading about 10 or 11 volts (it would be the mark below 12 on the dash gauge, i would consider it 10 since it's between marks at 8 and 12 but when it says 10 volts in the car i get 11 volt readings from a tester). Anyway, it would dip even lower if i would run the A/C at full blast or use the rear window defroster. But the other night i was driving with the lights on and the gauge kept creeping down until it was at about 9 volts, i took it straight home and let it run with all the electric equipment off for a few minutes and it made it back to 11 volts (according to my hand tester, it was about the same at the gauge too). I also noticed a buzzing noise from inside the engine bay that has never been present and didn't sound like it was coming from the alternator. My dad is coming up to check it out (i'm the enthusiast, he's the mechanic) on Christmas but if any one has had the same problem or thinks they know what it is please pass along your advice/experience with the problem. Thanks!

 

not really sure myself on this
but I would recomend running a few extra grounding wires since the stock mazda system sucks

also you might try to run a wire direct from the alt output to the pos on the batt as well see if that might make it a little better at least

one other thing I would say is d/c the pos bat cable then one end of your tester to the batt cable the other to the pos post on the batt and read how many amps/volts are going through with the car not running but the key set to acc and turn your radio and everything else off that you can
that way you can see how much draing there is running through the car when nothing should be on
think a small amount is ok being clock and such still use a little juice but not sure how much max
might want to ask someone else here