Subaru keeps dying


#1

Our 2005 Sub Outback w/ 58K miles dies every few days when not driving and requires a jumpstart to get it going again. The mechanics looked at it for 4 days and couldnot find any large electrical draw on it and it dies no matter what kind of battery is in it. The battery does not die if driven at least once a day, but if left for at least two nights… sure enough its toast.



Is the car a lemon? Are we cursed?


#2

If you are sure the battery is draining down due to a current draw rather than just having a bad connection to the battery then the current drain would seem to be delayed somehow. I would think that the shop that looked at it would have checked for an excessive drain. There are alarm systems made that will alarm the tech when the intermittent current draw takes place.


#3

The battery connection has been checked and determined to be just fine. There was not a current drain detected when it was last taken in. They did check for an excessive drain but did not find one durring their working hours.

If the intermittent draw would occur when they are not monitoring it then they would never detect it, correct?


#4

“If the intermittent draw would occur when they are not monitoring it then they would never detect it, correct?”

Sure, if they weren’t monitoring it at the time then how could they know except finding a low battery condition later on.

If the shop isn’t finding a drain problem then I would have to think that there is something else happening here. The normal current drain should be below 80 milliamps while the car is parked. Really, more like around 35 milliamps is a norm. If that is the case and the battery voltage is still going down, then the battery must have an internal problem.

The car should be able to parked at least several weeks without having a startup issue due to a low battery.


#5

The mechanics said that the current draw was around 30 milliamps and so, as you say, within normal range. The rub is that we have tried a new battery since the problem and the thing still keep dying.

Considering for a moment that we are not really unlucking when it comes to defective batteries, could there be something that is turning on in the middle of the night that is draining the battery?


#6

That’s what it looks like but I don’t know what it would be. Putting an alarm on the system overnight to trap the incident would prove it.


#7

Do they have alarms you can buy that would do this?

Thanks.


#8

They do but they may be fairly expensive and I don’t know of any brands off hand. You could make your own by placing about 1/2 amp fuse in line with the battery lead. Then put something like a small horn across the fuse leads. If the current gets high enough to blow the fuse then the horn should sound.


#9

Thanks for the suggestion.


#10

This testing method could be considered slipshod and backyardish in nature but you could try this.
Disconnect the negative battery cable and while shielding the battery terminal from the light (doing this at night is better), very lightly touch a sharp edge of the cable end to the battery negative post.
(Make sure the key is pulled, doors closed, etc.)

If you see a noticeable blue spark then you have a current draw worth worrying about; 30 claimed milliamps or not, and maybe someone at the shop was not holding their mouth right.
If you see a faint, light yellow spark then that usually means a non-issue and is caused by the clock.
Hope that helps.


#11

With todays electrical systems that idea may not work. Usually when the battery is connected the current surge is fairly high but then drops to a lower level. You also have to consider that some systems go into a sleep mode after the car is shut down and current draw goes down then, and the power has to be applied to the systems to do that.

I suspect that the measured 30 milliamp draw is correct since that is about what a normal system should be drawing. The only explination of still having a dead battery that I can think of is that something is turning on after a delay in time and draining the battery.


#12

I have noticed the spark when I connect the battery back up. It shows up blue, but does not happen every time.


#13

Some Fluke multimeters have the ability to record current draw over a period of timeNeed to get to shop with the correct equipment and the brains to interpet the data. You have a draw


#14

Some years ago I had a Buick Riv. that the battery would just mysteriously go dead. I thought it was the battery but tested fine and the store wouldn’t exchange it. One night I walked out in the garage and lo and behold the interior lights were all on. Traced it to the switch inside the door handle that would turn the lights on when the handle was pulled. Disconnected the wire and no problem since.

If it is so intermittant, I guess I would try pulling one or two fuses at a time, paying particular attention to any lighting circuits. Through trial and error you can eventually try to isolate the problem to the circuit. Brake lights, glove box lights, trunk lights, hood lights, and so on that don’t shut off are particular suspects. I also had a problem with the load level sensor getting fried and draining the battery. That one I found with the test light though since it was constant.