Overnight my 100ah battery dies. No lights on, nothing apparent as to being a load on the battery. I have even removed the trunk light fuse, just to make certain the trunk light switch had not failed. When I reattach the battery cables after charging the battery there is a good sized arc. I do not have a clue as to where to start looking as it is not like a direct short in a fused circuit. I do not know if a relay could have died or made up sealed.

Any thoughts appreciated.....

 

How old is the battery? I don't know a lot about electrical stuff, but are the battery cells full? You can top them off with distilled water.

 

Sounds like the battery is full (has an arc), but insufficient amperage is making it down the line.

Wild guess #1:

Battery acid on the line? Sandpaper the leads and the battery terminals, toss on a spoonful of baking powder and water (or battery cleaner if you have it).

Reattach and vroom.

Wild guess #2:

...is the battery more than 1 year old but less than 5 or did it spend a winter sitting uncharged? If so welcome to the new reality of cheaply manufactured batteries that won't hold a charge. I've gone through 5 in the last 3 years on various vehicles. You can have it tested at any parts store and then return on warranty to the place you bought it from.

Best of luck!!

 

There is a tiny 'door' in the front of the ignition key slot. Make sure it is not stuck open. If it is, use a light lubricant to free it up so it closes properly when the key is removed. This is a common cause of excessive battery drain on this model.

 

load test the battery

 

the little door in the key hole, when you pull out the key, do it slow, you should hear a click when it comes out, no click, may be stuck open.

 

Thanks for the tip!! It looks as if there is just the one "door" in the key switch. I did give it a dose of PB Blaster. Still draws a healthy arc. I would guess it to be between 5 and 10 amps.

 

You can always expect a healthy arc when connecting the battery. The computers in the car need to boot up and initialize, which draws significant current.

Then after several minutes of inactivity, they go to sleep, drawing only around 30-60 milliamps in sleep mode, which is low enough to keep the battery alive for weeks.

 

Hi , I had a similar thing when i first bought my xkr except that my battery would remain for 2-3 days(if i didnt drive it) then dead. Charging the battery became a hobby, I eventually bought another battery but it made no difference other than i could now drive while the other battery was charging.

my solution was.. to place a ampmeter between the positive of the battery and the positive cable. this enabled me to read how many amps were being drawn of the battery while the car is parked up. i then went one by one pulling every fuse until i found out those areas where the difference was the greatest.
If you find that for example the reading drops signifcantly when you pull the radio fuse , then leave it out for a few days and see if things improve.(this is where common sense comes in)

thats how i managed to fine my problem ...relatively quick.

maybe this gets you at least looking in the right area .have fun

 

Over the years, I've had 3 vehicles have battery problems. 1) Lincoln MKVII, 2) Range Rover and 3) Trailblazer. SO, a fairly wide scope brand wise. In each of the situations, the battery would drain flat dead over a 24 hour time span. In every situation, the problem turned out to be the starter relay, which is attached to the starter.
After fuses, that it the first thing I check now.

 

Well it is over????
I checked every fuse, relay, O2 sensors and the alternator diodes.
All well and good.
Then, out of desperation,sitting behind the wheel accuating all the switches and knobs, I then ran the electric seat adjusters. The passenger seat kept moving after I released the button. I then felt under the seat and the little box down there was warm.
It was drawing a continuous 5.5 amps behind a 15 amp fuse.