# car battery problem, suggestions welcome **URL:** \ **Category:** Factual Questions\ **Created:** [March 24, 2008, 2:34pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524 "2008-03-24T14:34:25Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![bryanmaguire](https://avatars.discourse-cdn.com/v4/letter/b/d07c76/32.png) [@bryanmaguire](https://boards.straightdope.com/u/bryanmaguire)\ **Post date:** [March 24, 2008, 2:34pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/1 "2008-03-24T14:34:25Z")
I bought a new battery and already it is flat. I tested it after i bought it and it was reading over 12V. I tested it again last night and it was reading around 12V so i wasnt worried. I tried to start it this morning and it wouldnt. Tested the battery again and it was reading only 5V. Any ideas how i can figure out why the battery is being drained so fast? ---
**Author:** ![A.R.Cane](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@A.R.Cane](https://boards.straightdope.com/u/A.R.Cane)\ **Post date:** [March 24, 2008, 2:46pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/2 "2008-03-24T14:46:32Z")
You probably need to take it to an auto elec. shop. It sounds like something in your elec. sys. is drawing power when the ignition is off. It shouldn’t take a pro very long to find the problem. ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [March 24, 2008, 3:05pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/3 "2008-03-24T15:05:28Z")
[QUOTE=bryanmaguire] I bought a new battery and already it is flat. I tested it after i bought it and it was reading over 12V. I tested it again last night and it was reading around 12V so i wasnt worried. I tried to start it this morning and it wouldnt. Tested the battery again and it was reading only 5V. Any ideas how i can figure out why the battery is being drained so fast? [/QUOTE] Either you got a bad battery (unlikely) or something is drawing power off your new battery. You sure you didn’t leave a dome light on or something when you tested it last night? ---
**Author:** ![HongKongFooey](https://avatars.discourse-cdn.com/v4/letter/h/c4cdca/32.png) [@HongKongFooey](https://boards.straightdope.com/u/HongKongFooey)\ **Post date:** [March 24, 2008, 3:09pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/4 "2008-03-24T15:09:35Z")
An acquaintance had the same problem and asked me to help him with it; we found a nick in the insulation of some wires was causing a short to the frame when he started it, sitting idle it was OK. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 24, 2008, 3:24pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/5 "2008-03-24T15:24:45Z")
Step 1 Recharge the battery. Step 2 Have the battery tested. Out of the box duds are not unknown in the car battery business. The last battery I bought for someone’s Volvo had sat for so long at the auto parts store it was DEAD when I got it home. Step 3 check for a current draw. Is the glove box closed and the light off, ditto for the trunk. Does the stereo stay on after the key is off? I have also seen issues with power door lock drawing batteries flat. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [March 24, 2008, 3:36pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/6 "2008-03-24T15:36:22Z")
Have your charging system tested. You should be putting out 13-13.5 volts under full load(headlamps on, heater/aircond full on, whippers on, etc.) I had a problem like that once, after a repair job(body work) the hood light only came on when it was closed. It was installed the wrong way. :smack: ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 24, 2008, 3:58pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/7 "2008-03-24T15:58:46Z")
First off the battery went dead while sitting, charging system has nothing to do with it. Secondly, your voltage listings for a charging systems are not correct. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [March 24, 2008, 4:47pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/8 "2008-03-24T16:47:22Z")
[QUOTE=Rick] First off the battery went dead while sitting, charging system has nothing to do with it. Secondly, your voltage listings for a charging systems are not correct. [/QUOTE] Sorry, \Not trying to start anything, as I am not an expert. I do know that it takes a load cell to test a battery for full charge and I don’t think that was done. What is the correct voltage to look for under load? When i see anything over 13 volts, and under 16 I am happy. ---
**Author:** ![gonzomax](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gonzomax](https://boards.straightdope.com/u/gonzomax)\ **Post date:** [March 24, 2008, 5:00pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/9 "2008-03-24T17:00:00Z")
I too bought a brand spankin new battery only to find it was dead. ---
**Author:** ![gonzomax](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gonzomax](https://boards.straightdope.com/u/gonzomax)\ **Post date:** [March 24, 2008, 5:01pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/10 "2008-03-24T17:01:20Z")
Be quick often the guarantee is determined by the born date. The warranty could have been used up before it was sold. ---
**Author:** ![FoieGrasIsEvil](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/foiegrasisevil/32/16638_2.png) [@FoieGrasIsEvil](https://boards.straightdope.com/u/FoieGrasIsEvil)\ **Post date:** [March 24, 2008, 5:05pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/11 "2008-03-24T17:05:32Z")
Yeah OP, you could start your troubleshooting with the battery itself by exchangin it for another one. A lot of the auto places will also happily test stuff for you too, if you ask. ---
**Author:** ![bryanmaguire](https://avatars.discourse-cdn.com/v4/letter/b/d07c76/32.png) [@bryanmaguire](https://boards.straightdope.com/u/bryanmaguire)\ **Post date:** [March 24, 2008, 5:25pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/12 "2008-03-24T17:25:59Z")
Thanks FoieGrasIsEvil for suggesting the simple things first. Turns out i had left an interior light on. The interior lights in my car are very dim and hard to see in daylight so i didnt spot it at first. I borrowed a booster pack from a neighbour and after 20 minutes idling the battery voltage is back to just under 13V. Thanks also to Rick for ruling out a problem with the alternator. Nothing in the OP suggests a problem with the altenator but several people have told me to check this first. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [March 24, 2008, 5:36pm UTC](https://boards.straightdope.com/t/car-battery-problem-suggestions-welcome/442524/13 "2008-03-24T17:36:55Z")
[QUOTE=gonzomax] Be quick often the guarantee is determined by the born date. The warranty could have been used up before it was sold. [/QUOTE] The battery’s I buy the store etches the purchase date into it, and w/ sales slip its good for 1 year. I do believe the sales slip isn’t even nessesary for that store.