I was having a problem with my old battery not charging so i bought i brand new red top and replaced the alternator, was perfect for a while but now it has slowly gone back to the old problem, turns over slow and sometimes wont start at all, the only volt gauge i have in the car is my pioneer head unit, it shows 13.7-14 with every thing off and the radio turned down so the amp isnt using much power and with the climate control on, headlights on and stereo at normal volume drops to about 13 - 13.4, when i turn the stereo up with the bass going none of the lights dim or anything like that.
A couple of times it has started fine then after driving for 5-10 minutes i park it for a couple of minutes then get back in and it wont start.
The two problems im thinking is the starter motor drainging a lot of power, this would also be why after a short run i cant start it, it drains so much power and i have not driven it long enough to get back in.
Or my alarm is draining it, either way how do i check to see what is draining power?