I'm sure its not the first, second, or even tenth thing you pay attention to when getting behind the wheel of your vette, but does anyone know what the voltage should be for a healthy battery? I've noticed it saying 14.1 usually, sound right?

Tonight its beautiful out so i take the roof off, hop in, and click click click. Ended up having to jump the car off of my dd and i'm wondering if its going to start in the morning. Giving me all kinds of nasty messages before cranking such as no fob detected, service car soon, etc. After getting it running the battery at idle was ranging between 13.3 - 13.8 and 14 tops while giving the car gas.

I thought DBS was only on '05s?

 

Any battery can go bad at any time. How much do you drive? How old is the battery? The voltage you reported indicates the charging system is OK. I replaced my battery at 22 months. My new Optima Red Top runs from 14.1 to 14.6 volts. My old battery ran about the same right up to the time it died.

 

I'm new to the car, but the service records i pulled before purchase showed a battery replacement back in January. I hadn't driven the car since Sunday, but did crank it earlier today for the express reason of making sure i didn't have any issues and it fired right up. Now there is a slight hesitation before turning over.

 

My battery usually shows about 14.3 pretty consistently if I'm giving it any gas at all.

 

A buddy of mine just called. he needed to use te regular key to get in. Voltage indicated 7 VDC! Service ABS yada,yada,yada on DIC. He doesn't drive it enough! It's on the charger right now! (Pulling 8 amps.)
He made me nervous so I put mine on my smart charger. I'm pulling 2.2 amps. I drove it yesterday. I'll check it in a couple hours.

 

Had the same problem last Friday. I was more concerned with the messages than the dead battery. Your reading of 14 or so during operation is fine. When I brought my car in for service they advised me of a bulletin for sudden battery drainage and did a BCM reflash which adjusts some of the systems that cause drainage when the car is off. The battery itself tested well, but I was advised that since the car was not used enough that I use a trickle charger for those periods where the car might not be used for an extended amount of time.

 

Normal voltage for a fully-charged battery is about 12.6 V, depending on temperature. The "float" voltage is about 13.8 V - this is the point where the battery will take some charge and about the voltage you'd run a trickle charger at. The normal charging voltage for these batteries is about 14.4 V.

So reading below about 13.8 V indicates that your battery isn't being charged. Readings between 13.8 and 14.4 V indicate normal charging. Reading about 14.4 V or a little more indicates a fully-charged battery. These numbers can vary a bit due to temperature and the accuracy of the meter.

So if you're reading around 14.1 V either your battery needs a fair amount of charging, or there's a problem of some sort that's not letting it get fully charged.

I'd fully charge the battery (overnight on a "smart" charger) then take a nice drive. Readings around 14.2 or so for the first 10 - 15 minutes are normal, but after that your voltage should be pretty close to 14.4 V. Much more or less indicates a problem.

Of course these readings should be taken with the engine running fast enough to provide charging current - say at least 1500 RPM.

 

I had mine on a trickle charger for about 3 days. ( 2 amps) Before starting I checked the reading thru acc. mode it showed 11.8. As soon as I started it, the reading was 14.5. It seems the 14.5 is good but what about the 11.8?

 

If your sure you did nothing wrong, leaving anything on or in wrong gear.. take it to a Chevy dealer and ask about the latest bulletin in the last month or so. There was a bulletin I believe in March that gave VINs 05 through a breakpoint in 07 for a programming update to the remote door lock receiver. Something about that system staying powered up too long if left in passive mode.

Was your door locks in passive mode? Tell the dealer to look up that bulletin, I think you may need the programming.

Normal voltage is 2.1 Volts per cell - stand alone/car off. So right around 12.5 to 12.7 V or so. Running it's going to be a couple volts higher indicating it is charging, you'll see 13's to 14's Volts running.

Accessory mode, engine off is could be in the low 11's with all the systems on but no charging.

 

Last Friday I had a dead battery. I brought it to the dealer on Tuesday and they did a BCM reflash ( sounds what you are describing). Because of lack of use over the winter they suggested using the trickle charger.I am wondering though, after 3 full days using the trickle charge, the 11.8 in acc. mode is still low. The charger indicated that the battery was fully charged is the 11.8 in acc. mode good or should I bring it in for another check?

 

You just never know when.

 

11.8 in acc mode is absolutely fine. That's even higher than I've seen in several of the vehicles I've owed. Accessory mode without the engine running has a lot of modules and systems powered up, so it will take the voltage down.

Now if you saw 11.8 at the battery with a separate hand held volt meter with everything completely off, then I'd think you have a low charged battery. Everything off, you should see mid 12's at the battery. You can't read it that way through the DIC, so many people do get concerned when reading it through the DIC. You just have to realize when the DIC is on in acc mode, so is a lot of other stuff and it is normal to see voltage in the 11's/high10's.

Trickle charger is a great idea for anytime the vehicle will sit for more than 2 weeks. If it can't last 2 weeks without going dead, something is wrong.

 

I had the same experience. Someone pointed out that when you put the button on acc., your lights may come on,your radio is on, your blower motor is on and about 40 relays are doing a jig. All will reduce the battery voltage. If you went directly to the battery with a voltmeter you will probably get 12.6, plus or minus a tenth of a volt or a fully charged battery. The DIC will always read at least 1 volt less. There is nothing wrong, at least not yet.

 

One more thing is when you open the door to pop the hood the interior lights go on. I wait a few minutes for them to go off and the battery settle down before checking it with a volt meter.

 

Brought in for a check. a voltmeter on the battery showed 12.6 and somewhere around 685 in amps.

 

A voltage reading in the 11s on the DIC indicates something is wrong (maybe only a low battery, but it could mean a wiring problem). Wiring resistance in the primary circuit should be under 0.05 ohms (typically 0.01 ohm), otherwise the starter won't be able to whip the engine over at normal cranking speed. Even with a 10 amp accessory load (normal accessory load with the lights off is only about 2 amps), a 0.05 ohm resistance should drop the voltage seen at the ECM by only 0.5 volt (voltage drop is equal to current times resistance or E=IR), so a fully charged battery should read at least 12.1 volts (12.5 volts with the lights off and only the normal 2 amp computer load being drawn).

The voltage reported by the DIC is the voltage measured at the engine by the ECM. So if the voltage reported on the DIC is low, voltage at the engine is low too, and that indicates either an actual low battery or a problem with the wiring between the battery and the engine/ECM. Usually, the latter will be a loose or corroded ground connection, though a high resistance in the hot primary wiring is a possibility too. This is a problem, and will show up as poor starting, running, and battery charging performance.

Remember that to read battery voltage via the DIC the engine must be off. Hold accessory for 10 seconds to put the car in ignition on engine off mode to make the reading. When the engine is running, you are seeing charging system voltage, not battery voltage. A healthy charging system will show a voltage on the DIC (with the engine running) of between 13.8 and 14.4 volts. The higher voltage means the charging system is trying to charge the battery. After the battery reaches full charge, the running DIC voltage should drop to 13.8-14.2 volts indicating the car's charging system (regulated by the ECM) has determined the battery is fully charged and is maintaining only a float charge on the battery. (A higher voltage on the DIC means either the battery isn't yet fully recharged, or there is a problem with the primary wiring, or the charge regulating circuit in the ECM.)

One of the electrical issues with the Corvette is that the minimum required operating voltage for the computers is close to the normal full charge voltage of the battery. A battery voltage of less than 11.5 volts will cause the computers to go wonky, throwing spurious codes and operating erratically. That represents a battery with 47% charge.

Of course starting batteries are never supposed to be discharged below 80% charge. They can be damaged if they are (deep cycle batteries can stand being taken down to 20% charge). But folks who don't drive their cars frequently or long enough to fully recharge their batteries are going to have issues even if the car's battery and charging system are operating perfectly normally. If there is a problem, sulphated battery, higher than normal primary circuit resistance, ECM voltage regulation problem, etc, then the issues can be severe.

The best defense against battery problems is to drive the car daily, and drive it at least 30 miles (half an hour) between starts. This lets the charging system keep the battery near full charge. If you can't or won't do that, then you might consider a battery tender. You also want to keep the wiring in top shape, check connections frequently for signs of looseness or corrosion. Correct any problems as soon as they are discovered. This will go a very long way toward eliminating battery related complaints.