RunYun

Well I am pretty sure I know the answer to this, but thought I would throw it out there as I have changed a battery in the past only to find out it was a starter problem two weeks later. My battery voltage was typically running over 17 volts. Car started with no hesitation. I noticed it seemed to be a bit lagging on start recently and I now see it bouncing around 13.9 to 14.4 volts. I had the battery load tested and it said the battery was fine, but they could not test the alternator because the battery was not at full charge. So I bought a trickle charger and charged it. Start the car and same voltage and lagging start. Given the voltage on the battery and short amount of time it took to charge I am guessing its a bad battery. It's an AC Delco 650 cranking amps. Any thoughts or similar experience?

LS BRAVADA

iTrader: (4)

Does battery voltage drop wile cranking engine

07CTS-V

iTrader: (6)

My brand new battery and alternator only get to 14.2 V on a good day.

erickcastillo95

iTrader: (1)

could be a ground bro same thing was happening to me

69stangscj

iTrader: (3)

17v is too high for it to charging at. You may have two problems, the voltage regulator inside your altenator may have went bad and cooked your battery..... 13.9 to 14.4 is normal, or could be a ground. I would have thought 17v would have set off some type of alarm?

RADEoN

iTrader: (12)

put a volt meter on it.

sounds like the voltage regulator died in the alt.

RunYun

Thanks. I put the battery on the trickle charger overnight. Will see what the voltage looks like in the am. It said ok at 17 volts and now at 14 volts. Just noticing car does not start as easy. Battery could be damaged.

RADEoN

iTrader: (12)

Shut off the trickle charge and see what it reads on the posts with a volt meter.

RunYun

It reads about 11.8 when the car is off. Over 14 when it is running.

DMM

OE type battery? If so, that's the problem. They get a high resistance to ground internally and do all kinds of weird crap. Is replace the battery and if you ever see 17 volts again get an alternator. Voltage should never go above 14.7 volts...ever.

RADEoN

iTrader: (12)

My Aurora goes up to 15.2 or 3 in very cold weather. Has since I got it, with a stock alternator and aftermarket. That's normal, but 17 isn't.

RunYun, compare the volt meter voltage to the DIC voltage. If it is different, and the battery terminal is reading 14.x while the DIC is reading 17, then you aren't looking at a real charging system problem.

heavymetals

iTrader: (3)

The grounds are so crappy in the CTS-V (gen 1) that the only way to get an accurate voltage measurement is to use the negative post on the battery for your ground reference.

If you are at 17 volts across the battery, the regulator (internal/part of the alternator) is toast and so is the battery (cooked).

I just replaced the alternator (installed heavy duty high output monster) and it is a chore.

Install required the addition of redundant power and ground cables (0/1 gauge) directly to the battery.

RunYun

Battery finally tested bad. I am guessing it must have been failing internally. Turns out it was the original battery. Getting 6 years out of a battery especially in Texas is a pretty good deal. Since I drive downtown for work now I bought an F150 and only drive the V on the weekends. Letting the battery sit for 4-5 days may have just pushed it over the edge. Oh well.