Auto battery problem

Some time ago I'd occasionally have a dead battery in my car. This annoyance went of for about two weeks. One day at dusk I pulled in the house stopped the car got out and walked down to the end of the driveway to check the mail. On the way back my brake lights suddenly went on, all by themselves! Turns out the whole problem was brought on by a failing brake light switch. I'm not suggesting you have a bad brake light switch, only that it could be something as simple as that.

I park in the garage and NEVER leave the key in . Seems it would lead to a bad habit of accidently leaving the key in at other places.

Even more shooting from the hip here..
In many modern vehicles (esp those with just a start button) leaving the key inside the vehicle keeps the cars computer "awake" and will kill its battery fast. This also goes for many keys that have a chip in them too.

Just shooting from hip....clean battery terminals and the inside of the clamps. Sounds like a corrosion issue rather than battery.

Trackrig wrote:

I don't know what systems are supposed to need the power drain all of the time? When I disconnect the battery cables while we're gone, the only thing that I see that needed power all of the time was the clock that needs resetting.

Bill

Perhaps among other things, the radio receiver and such for the keyless entry consumes some power. There may also be a simple alarm system of some sort from the factory.

I do agree that there's little excuse for a car that can't sit parked for a couple of weeks without killing the battery, though. That's rather excessive, especially if it truly is that way by design (and not just your dealership trying to get out of performing a bunch of tedious diagnosis).

enblethen wrote:
Parasitic loads can draw down your battery over a week or so. These loads vary by vehicle. If you are not going to use the vehicle for an extended period of time, install a battery disconnect. Charge the battery to a full charge on a slow rate.

And this made me remember that some dumb (stupid) mfgs design the parasitic loads into their rigs. The DWs Ford Escape, which we don't tow, will go dead after one weeks of just sitting in the garage. After this happened a couple of times, we took it into the dealer we bought it from and they said, "Oh, there's nothing wrong with it, that's the way it's designed." They said there's a bunch of electronics that needs to have power all of the time.

They asked us why we weren't taking the keys out of the ignition at night "like everyone does?". I asked why and said that's why we park it inside of our garage. The only fix was to take the key's out of the ignition every night and lay them in the seat. Even with the keys out it still draws power, though just not as much. If we're gone two weeks I have to either install a battery minder or disconnect the battery cables. Again, Ford says it was designed that way. Stupid engineers.

I don't know what systems are supposed to need the power drain all of the time? When I disconnect the battery cables while we're gone, the only thing that I see that needed power all of the time was the clock that needs resetting. (Did I mention anything about stupid engineers?)

Bill

Parasitic loads can draw down your battery over a week or so. These loads vary by vehicle. If you are not going to use the vehicle for an extended period of time, install a battery disconnect. Charge the battery to a full charge on a slow rate.

Yes, it sounds like you have a major drain someplace. Here's a temporary fix if you're out traveling. Any Napa or Auto Zone should have battery disconnects. No, I'm not talking about the ones you have cut the cables for and wire in. To install these you remove a batter cable from the battery, install the disconnect to the battery terminal and then the cable to the other side of the disconnect. Should take about five minutes. Disconnect the battery between uses until you find your drain.

Bill