Drain on Battery

Get the battery load tested if it checks out-get a parastic drain test to find out where that short circuit exist within the electrical system. Or do below

Read the article below, it will help https://www.2carpros.com/articles/car-battery-dead-overnight

I've had the battery checked / tested - Nothing was detected as being wrong. That is why I ultimately purchased another battery. To my surprise the vehicle is doing the same thing - even more often.

Like I said earlier you have a short circuit that's eating up the battery you need to have the parastic drain test perform-If its not a parastic drain then have the alternator tested might not be putting out reconditioning the battery-

after many costly trips to the dealer, my 99 jag still goes dead every 3 days, (if not driven.) i found a usefull item called a battery brain. its a device that hooks to the battery terminal and will shut off the connection to the battery when it reaches a certain drain point it comes with a remote control that attaches to your keychain. one push of the button and the battery is reconnected. the cost is approx 95.00 and can be ordered on line, at batterybrain.com. my radio retains all the preset items, i only have to reset the clock. ( when you push the reconnect on the remote control, the battery has plenty of power to start the vehicle, installation is very easy, the kit comes with everything you need and it fits in the trunk well right next to the battery. i installed this over 5 years ago, and have not been stranded since.

My battery was "suddenly" dead last week when I came out from work. The car was jump-started and AAA said the battery was fine but something was putting a drain on it - most likely an electrical short. I have had 2 places do a battery load test just to be sure it is definitely not the battery. One said replace the battery but it could also be the alternator going bad or a short or both. The other (chain that specializes in batteries) said it was not the battery but the alternator only had output of 13 amps and probably needed replacing. He also "tested" the battery for a short in some other area by removing the negative cable and touching a wrench to the battery post to see if it would spark which it did. So he said I could have two things going on. Do you agree with these dx? What should I do at this point? I do not want to get stranded but I also do not want to get ripped off by my mechanic or a dealership. When I called my mechanic about this to begin with he immediately said replace the battery.

If the load tests done on the battery and alternator satisfys you-get the electrical system check for a short circuit

I do not feel like you answered my question. You did not address the amp read-out nor did you tell me if you agreed or disagreed with the previous suggestions. As I am not a mechanic and the reason I came to you with the question, telling me if I am satisfied with the battery and alternator tests does nothing for me. How am I supposed to know if those should satisfy me or not.

You've been bringing it in to the people that specializes in battery and alternator. If this items are being load tested it will finger it at no time between the two.

Okay-get the battery load tested for 10secs if it doesn't hold 9.6 volts on that time frame-its defective.

Same as the alternator if it doesn't come up 10% within the alternators's output its defective

NOTE: but the alternator only had output of 13 amps and probably needed replacing. Is this readings being taking under a heavy load?

Last
My battery was "suddenly" dead last week when I came out from work

I gave you how to check a battery drain-I'm suspecting a short circuit in the electrical system that will cause that failure last week.

My boyfriends 1999 Jaguar XJ8 Vanden Plas' battery does not seem to hold a charge. The car sits all winter long and come spring time I have to jump it to get it running. Last year was the first year I had the car and had to do that and it seemed to work fine after that one jump start. Now this year after jump starting it the one time, it does not want to start again. All other accessories in the car seem to work, but it won't start unless I jump start it again and then once I turn the car off it won't start again unless jump started. I believe this could be a bad battery needing replacement but am wondering if there could be some other problem. If someone could please respond I would appreciate it.

Thank you,

If the battery is load tested and okay-have the starter motor, starter relay,clutch switch or transmission range switch and igniton switch checked out -double check connections at the battery and starter

If you're going to long-term store a car like an XJ8, you need to put a battery tender on the battery. Otherwise you'll find it dead after 2-3 weeks. You can buy an inexpensive one at Wal-Mart, about $20. You didn't say how old the battery is, but it sounds like it's at least 3 years old, and probably older.

Take the battery to your local auto parts store and have them load test it. You'll undoubtedly find that it's 1) not charged, 2) not taking a charge, and 3) needs to be replaced.

We went and got a new battery and by gosh that seems to have been the problem. Thank you for the responses. The advice about the battery tender is great since we don't plan on driving it during the winter and here in Minnesota those can be quite long sometimes. Thanks again!!