Dead battery. How long should I Drive to recharge it?

Usually a 30 minute drive will do the trick. Or, just let it idle in your driveway for awhile.

 

If your battery is dead dont try driving to recharge it. This sometimes puts too much of a burden on your alternator and burns it out. Get a battery charger and fully charge the battery before you take of.

Mel

 

A week isn't that long at all to drain that much, you might just put a new battery in. How old is the current battery?

As someone else said, alternators aren't cheap.

 

Correct answer !!!


" serenity now "

 

And don't remove the battery charger until the battery reads 14.2 V.

 

1 week seems pretty common. At least Dave Rocks seems to think so. I guess it depends if your car was assembled on a Wednesday or not.

https://www.ferrarichat.com/forum/143254459-post15.html

 

you have a drain somewhere..

 

I highly recommend removing the front right wheel and inspecting the battery terminals and cables for corrosion. When my car was having battery trouble, I decided to inspect and my ground cable was so corroded it needed replacing. I also replaced the battery and now keep it on a tender at all times. A bad ground will end up ruining your battery even if you keep it on a tender.

 

I also think there is something else going on....Mine sat for a month and fired right up. I often go more than a week or three without driving it with no problem. I just got a battery tender because it will be sitting for 4 or 5 months. If its going to sit for extended periods you might want to consider that option.

 

My two cents: At the first glance 12.56V is ok. However, the battery should be testet under load. To charge a battery the voltage should be a little higher than 13.8V. For me that voltage eems to be a little on the low side.
A battery that is not completely charged contains leadsulfate. First there are only small cristals which will dissolve when the battery is charged completely. However, over time the small cristals will grow. Larger cristals will not dissolve if you charge the battery. I bought a Ctec charger and charge my batteries every one ore two months. Even if I have driven my cars for some hours at higher speed the Ctec needs some hours to completely charge the batteries.

 

I plug mine into tender everytime I park it. I think a well kept battery is better on an alternator. My 2 cents.

 

i would suggest taking the battery out charging it, then load test it. Most auto parts stores will do this for free, or you can buy a load tester. They aren't very expensive. All they do is simulate a heavy load (like starting) for a period of time. Batteries can read good voltage and fail a load test.

To test parasitic drain. Charge battery. Turn everything off. Remove the negative battery terminal and place a test light light between the negative cable and the negative battery post. If it lights bright, then current is flowing and something is drawing. Using a voltmeter is of course better and more accurate. Cars should draw some depending on the type of electronics. If you do have draw with everything off, then you can start checking circuits by pulling the fuses until you see a change in the voltmeter.

In my experience, if you have run the battery dead, its days are numbered. Car batteries don't deep cycle well. HTH

 

Mine makes it 2-3 weeks before it needs a charge.

 

The alternator charges around 14 volts.
If you were driving the car for 30 minutes or more and shut it off
the voltage should be about 12.75 volts across the battery terminals.
As the car sits.....over days... the voltage will drop (due to the load from the ecu).
Is your reading of 12.56 volts immediately after shutting the motor? If so then the
battery is suspect. If its after several days then this is normal.
I would never charge a dead battery by using the alternator....you can burn out the alternator by doing this.
Buy a real heavy duty battery charger for recharging dead batteries and a ctek charger for maintaining good batteries.