ThomasM

I traded in my 2006 Impala SS for a brand new 2014 2LTZ. I love it!!

The 2006 never seemed to charge the battery enough so I had to hook up a trickle charger if I wasn't going to be using the car for a number of days.

The 2014 is just the opposite. In my opinion it OVERCHARGES the battery-it normally sits at 14.6-14.9 volts!! I measured it using an accurate voltmeter connected to one of the accessory lighter plug outlets AND verified it using the INFO section of the DIC (which, of all things, lets you view battery voltage, coolant temperature and other things long missing from instrument panels).

The dealer's laughable answer was "that's controlled by the computer". Uh-huh.

If anyone with a 2014 Impala could take a minute, I'd really appreciate what the battery voltage meter in the INFO section of the DIC is reading on your car.

Thanks!!

Todd2869

13.4 on mine.

Yours sounds like, even though on the high side, it is within the normal range.

ThomasM

It's pretty bizarre. One day it sat at 12.6!! (Maybe it thought the battery was fully charged).

In any event, if it fries the battery or any of the electronics I'll just get a new one for free under the bumper-to-bumper warranty. I got TWO of them for free in the first two years of owning my 2006 SS until I realized that it barely kept the battery charged. After setting up a Battery Tender trickle charger whenever I wasn't going to use the car for several days the battery kept going for 6 years and was still going strong when I traded it in!

tech2

14.9 won't fry a battery.

The ecm does control the charging system. Depending on the charging mode, the charging output can vary.

sulfation mode
charge mode 13.9-15.5
fuel economy mode 12.5 - 13.1
headlamp mode 13.9- 14.5
start-up mode 14.5 volts for 30seconds
voltage reduction mode 12.9

the battery warning system will set when system voltage is outside 11- 16volts

a normal fully charged battery is 12.6volts. If its reading over 12.6 there is a surface charge on the battery from being charged.

All Normal. As the dealer told you its ecm controlled and the system is operating as designed. Why do you find fault in this?

ThomasM

Interesting information. Did you get this from an official GM publication for the 2014 Impala? If so, my dealer was right and I have nothing to worry about.

I wonder how the ECM decides which "mode" to switch to. Obviously, on one drive it switched to "fuel economy mode" but it usually seems to be in "charge mode".

Also, you did not list a voltage for "sulfation mode". I assume this is right when the car is started. Do you have that voltage range?

Again, thanks for the info...

in2pro

As a side note, keep in mind that newer vehicles have many modules that stay powered up for a period of time after the vehicle is turned off, upwards to 10 minutes.... that can draw the battery down and can be exacerbated by having personal items plugged in like phone charger, GPS, IPod etc...

from personal experience with an 07 Tahoe that has a similarly controlled charging system, expect lower life span from your battery no more going 8-10 years... mine have all fallen out at about 3 years or so....

ThomasM

Well, you can't draw the battery down with personal items anymore-the lighter plug convenience outlets as well as the 120 volt AC outlet (on the top-of-the-line MyLink system) all power down when the car is turned off and the 10 minute "retained accessory power" system times out (or the driver's door is opened).

Chevrolet seems to have figured out about the computers and other modules that suck power when the car is off also. According to the manual, the computer monitors battery voltage when the car isn't being used and begins turning off systems as it drops. The manual even says that if the battery gets so low that systems the owner might notice aren't working (the radio?, OnStar?) it tells the owner with a message on the DIC display.

As for your Tahoe, when researching why I had two batteries in my '06 Impala fail in as many years, I did a bunch of internet research and I also did some testing on the car itself. The charging system back then was pretty stupid-it just kept the battery at 12.8-13.0 volts. Since this was when the sealed, maintenance-free batteries first came out, GM must have been worried about OVERCHARGING, since you can't add water and overcharging would damage them. Since I am retired I often didn't use the car for 3 or 4 days-and just like your experience the computers and systems drained the battery. I discovered this the first time on one cold, winter day when the car barely started. Unfortunately, by then the damage was done but I just assumed it was a bad battery and so did the dealer. But when the same thing happened a year later to the SECOND battery, closer examination revealed what I explained above.

The solution was a clever little gadget called a Battery Tender. It looks like a plug transformer and puts out just 750mA. (Three-quarters of an amp) But it's microprocessor controlled and it charges the battery and then switches to "float" mode which keeps the battery fully charged without damaging it. The folks on the internet that raved about this product use it on boats, campers, and motor homes that are put in storage for months. I hooked this thing up every time I wasn't going to use the car for a couple days.

Sure enough, it did the trick. The last dealer-supplied battery was installed in January 2007 (I bought the '06 in September '05). That battery was still in the car starting it aggressively when I traded it in last month!!

in2pro

Glad to hear you are happy with your purchase
If you have not done so yet, you may want to sign up for the "My Chevrolet" its a great way to track your maintenance history as well as obtain other useful information on your vehicle...

tech2

I gave you the short list. There are to many variables for me to list them all. The short answer is the ecm decides what to do based on information from numerous input sensors.

This is all factory information.

tech2

your 06 impala's charging system was also ecm controlled. IMO your old car had an unresolved problem. It is not normal for a car's fully charged battery to discharge in 4 days. 30days yes, 4 days...no.