Battery Drain Question

[autobonrun]

When just sitting, my battery appears to be draining faster than it should. Other than the clock, is there anything else that will be pulling current when the car is off and the alarm not activated?

I do notice that when I reconnect the negative, there is a substantial spark. Is this normal?

If I measure the amount of current being drawn, is there a figure given by the factory that can be used for comparison?

thanks

[Argo]

If you know the battery is good, to isolate the source of drain you could disconnect a cable from the battery and put a multimeter between the cable and the battery terminal. This will tell you the amount of outward current flow in the car's resting state. Then you can start pulling fuses one at a time and, by checking the meter, see if removing that fuse cuts this outward flow. If so, that circuit is a good place to start looking for a short or excess consumption.

I think there is a thread in the archives giving details of this procedure.

Argo
88 Targa

[1bar]

A couple of ideas:

1. Be careful putting a DVM (digital volt meter) in series with the battery. When you initially make the connection, most loads in your car will draw an "inrush current" - a large surge just for a fraction of a second. This, combined with the inductance of the wiring is the source of the spark you notice.

My DVM has a small protective fuse in series with the current measurement connections inside the instrument. The inrush will blow this fuse. Fortunately, the DVM I did this to had a replaceable fuse - many do not! If you blow it, you may be buying another meter!

Disconnect the negative terminal from the battery. Hook a clip lead from the negative terminal to the body, and leave it connected after the initial spark. Then hook your ammeter between the negative terminal and the body. NOW pull the clip lead - your meter is in series with all current flowing through the battery, but you didn't blow the fuse (only the tip of that clip lead is gone).

2. I KNOW why my battery dies in 3 days. The stupid radio the PO installed has a backlight that draws 400mA (0.4A) all by itself. If I disconnect the radio the battery would last for a month (I'm hoping Mrs. Santa Claus will bring me a new MP3 player for Christmas

You will probably find something along these lines is your culprit. Pulling the fuses one by one as Argo suggested is definitely the best systematic approach, once you've got the ammeter in the circuit to see the effect.

[Kurt peterson]

My car draws .2 amps and my new Bosch Silver Batt. is dead in less than 2 weeks. My initial draw is .4 amps and I also get a spark, due to thye CD changer, trunk light, and a relay somewhere in the back that energizes, when I hook up the Batt. (I'm still looking for it).

My new Ford Escape drams .1 amp. I think .2 is too high but it's not that bad. I'm wondering if I have something that "comes on" when the car is just sitting there? I'm still looking.