Help with dead car battery

[Bert Kemp]

So my car sat for 11 days after my knee replacement. yesterday I thought I could get out and strt the car, well the battery was dead. So I put the charger on for about 5 hrs and it started fine, shut it off and left it on charge till almost dark another 3 hrs. This morning I went out and the battery is dead again.

So my question is .....is there a meter or a way to test and see if their is a draw on the battery when all is shut off??

[Jerome Stanek]

You can have an auto parts store check the battery charge it up before you go and they will test it under load to see if any cells are bad.

[Bryan Lisowski]

IN today's cars there is always something requiring the battery. Most likely it would be better to buy a new battery.

[Paul F Franklin]

Assuming it isn't an ancient model, you would get a dash warning if the alternator wasn't delivering current (charging the battery). The exact warning varies from model to model and year to year, but if you have no warning indicators lit when the engine is running, then you either have something drawing a lot of power when the engine isn't running (unlikely assuming you didn't leave lights on or similar) or a bad battery, most likely a dead cell. As Jerome mentioned, any auto parts store will be happy to test it for you and most will install the new battery, if required, for free. Automakers are using smaller batteries these days to save weight, and will all the power needs of modern cars they just don't seem to last as long as they used to.

[JERRY BRINKMAN]

Assuming it isn't an ancient model, you would get a dash warning if the alternator wasn't delivering current (charging the battery). The exact warning varies from model to model and year to year, but if you have no warning indicators lit when the engine is running, then you either have something drawing a lot of power when the engine isn't running (unlikely assuming you didn't leave lights on or similar) or a bad battery, most likely a dead cell. As Jerome mentioned, any auto parts store will be happy to test it for you and most will install the new battery, if required, for free. Automakers are using smaller batteries these days to save weight, and will all the power needs of modern cars they just don't seem to last as long as they used to.

You can connect an amp meter in series with either battery cable or using and inductive amp clamp. Draw should be under 75 milliamps after all modules go to sleep, (may take up to 45 minutes on some models). If there is a excessive draw now the hard part is next. You must determine which circuit is the problem. This is not a task for the average person or unskilled mechanic.

[George Bokros]

I had a battery that was less than a year old and when I had my car serviced they found the battery was bad, not dead but unde rthe spec cranking amps of the battery. Replaced under the battery warranty. Get it checked at a parts store. They can also check it in the car.

[Brian Henderson]

That happened to my daughter's car over the summer. We put a new battery in her car, it died after 24 hours. There was a switch somewhere that failed and her rear lights stayed on all the time and that just drained the battery. It was a $200 repair. Get the battery checked out to make sure it holds a charge, then look deeper if necessary.

[Dan Friedrichs]

You can connect an amp meter in series with either battery cable or using and inductive amp clamp. Draw should be under 75 milliamps after all modules go to sleep, (may take up to 45 minutes on some models). If there is a excessive draw now the hard part is next. You must determine which circuit is the problem. This is not a task for the average person or unskilled mechanic.

Be careful with the amp clamp - the cheap ones usually only measure AC.

But otherwise, yes. Put the meter in series with the battery and measure draw. Pull fuses until you've found something drawing too much...

[Bill Orbine]

Disconnect battery. After it's fully charged, check voltage later(next day) after first reading and compare. If significant voltage drop, battery is likely bad. If good voltage, something on the vehicle is likely draining battery. This is just very simple basic if you not have the tools.

[Bert Kemp]

thanks I'll try this as Im not good with meters I have a voltage meter but not sure what they mean by meter in series with battery?

[Brian Henderson]

thanks I'll try this as Im not good with meters I have a voltage meter but not sure what they mean by meter in series with battery?

If you have a battery charger, they almost always include a rudimentary meter on them.

[Jim Koepke]

A good charge on a batter should give a voltage reading in the 13V range with the car not running. When the car is running and the alternator is charging a volt meter will read in the 14V range.

Watch the meter when the car is turned off. The reading should be fairly steady. If it is dropping something is draining the battery.

In the old days we used to just disconnect the cable while in the shade and touch the cable to the battery terminal and watch for a spark. The bigger the load, the bigger the spark. That doesn't work well with todays system because some will draw a large current when reconnected, causing a larger spark.

A decent amp meter is a better way to monitor battery drain with the system turned off. As mentioned previously, removing one fuse at a time can help isolate what is causing the drain on the battery if it isn't a bad battery or charging system.

Beyond this, trying to explain how to measure electrical circuits and explain the problems that can ensue could take a lot of time and effort.

jtk

[Paul F Franklin]

Be aware that with many newer cars, disconnecting the battery without using a memory saver or similar device can erase radio settings, saved seat settings, phone pairing data, and the like. Maybe not a big deal, but my wife probably has 30 or 40 radio presets on her car between AM/FM and satellite......She would not be happy if she had to redo them all.

[Bert Kemp]

Not worried about losing settings or anything like that. All I want to know is if theres an abnormal draw on the battery when the car is off or if the battery is bad. I put the charger on it early this morning will let it charge till the charger shuts off. I will then let it sit over night disconnected and see what it read in the morning. Or maybe be3 bold and take it to auto shop and have them check it .My problem with that is they can always say its bad just to sell me a new battery and those places always have high priced battery's

[Brady Watson]

...those places always have high priced battery's

It should still have a pro-rated warranty...don't let them rope-a-dope you.

Hopefully you're able to find a good mechanic that doesn't just throw parts at it on your dime...anybody can do that.

Not sure what the big deal is about losing radio/clock settings...are we that spoiled?