Without the alternator, the battery will eventually discharge. I've read some discussions on here but don't want to spend more more then I can afford so please any valuable knowledge is greatly appreciated. OK, I use this truck about twice a year, last winter both batteries died, so I replaced both batts. This usually indicates a bad voltage regulator. If the output voltage reading is 16 volts or higher, there's an overcharging problem. I replaced the alternator with one that I got from a salvage yard (to save money) but it is still over charging at the same voltage. Enter your ride HERE to be a part of this months Ride of the Month Challenge! All connections/grounds are tight. I have a 2006 Buick LaCrosse with the 3.8 L motor. If voltage goes up during this check, repair or replace the internal regulator. 07 GM SI alternator internal regulators can be checked as shown in the photo. I thought alternator was overcharging,would vary from 14.8 to 19.2 volts.Bat light would come on but not always. Naturally changed the alternator not knowing gm since 2010 no :helpHey guys, fired up the Duramax today and noticed its overcharging, voltmeter on dash reads 17+ volts, yet truck runs great. You can test to see if the alternator is overcharging, using a simple voltmeter. Hello, I bought a 2013 Chevy Cruze back In April of 2019 and three months after we smell an egg smell in the car and the battery goes dead we find out that it is over charging cause it reads at 15.2 plus. I verified voltages with my DVOM at the alternator and battery. Recently acquired 2006 silverado with lq9 engine. If the alternator sensing terminal cannot sense a voltage, the regulator tells it to go to full output and that is 18 volts. My story. Last week I found out that the alternator was overcharging (charging at around 15.5-15.7 volts.) My 140 amp powermaster (#37294, one wire) GM style alternator has started overcharging recently. Want Answer 0. Also put in new battery at that time as. Had overcharging issue and replaced alternator after mechanic said issue was internal voltage regulator. Trying to figure out an alternator overcharging issue. Jump to Latest Follow Hey Everyone! If you have a poor connection anywhere that the sensing wire is connected to it may cause the regulator to sense a low charge and increase the field current to the alternator field causing it to overcharge. However, if the alternator isn't working correctly, it may send too great of a charge to the battery, which is known as overcharging. Hi, this is my first post to the forum. New alternator, Still overchargingWTF. Posted by Crystal Scott on Oct 13, 2013. This condition is dangerous to your car's battery and electrical system. Alternator overcharging 2005 chevy cobalt battery overcharging even after replaced with 2New alternator in 1week.Any common known problems with this or suggestions of what to look or check next? At idle it charges at 16A, at 2000 rpm pegged on 18A. I see a lot of answers, some good and based on what some fellows have seen in regards of the question, and some answers. Changed alternator and have same thing happening.Cooked the battery.Have system voltage with engine off at alt sense fuse and initially when engine starts but within 10 seconds voltage jumps to over 19v,slowing the engine. The car has 72000 miles on it. If voltage seems to fluctuate during your test, switch your voltmeter to the AC voltage scale and take another output voltage reading with the engine still running. Recently noticed my 2014 2.5 LT overcharging to an excess of 15.3 volts.