Dying Battery

[CaptainYeroc]

Hello,
I bought a Porsche 944 a couple months ago and the battery seems relatively new. Yet, if the car isn't started for a few days the battery dies. Could it just be a bad battery? or could there be something that's draining the battery while the car is off? If so, how could I find the problem?
Ideas would be greatly appreciated!

[flash968]

clean your grounds, especially the main

look for something draining the battery (glove box light, stuck door pin switch, hood switch, etc)

if that does not solve the problem, do a hydrometer check on the cells

[ballysdad]

check for parasidic draw on battery..should measure less than 60 milliamps with power off and key out..if your hood light works diconnect before testing. Put a voltmeter between the positve cable and the positive terminal and measure. If it measures too high pull fuses 1 by 1 until it drops that will narrow circuit down.. Before all that take the car to sears for $12 they will make sure your battery is fully charged and altinator will work properly with a load..AND CHECK GROUNDS ..

[AKCJ]

To check for parasitic draw you'll need to check the amperage draw between the + battery terminal and the + battery cable (after you take the cable off). I think that's what Ballysdad meant to say. You can get some idea by using a simple test light but amps is what you really need.

Note that a battery that has been drained down several times will probably not (ever) be any good.

It's usually free to get a battery load tested at NAPA or other places.

One good test would be to read the battery voltage before starting the car, then start the car and make sure the voltage reading goes up. If it doesn't then your charging system may not be working.

Sometimes a no start is just a bad cable or bad connection at one end of one of the cables. On a car this old I would probably get all new cables - just went through this last week on the wife's Saab when the temp dropped to below zero.

[bud9344]

Check the Battery for a FI car the load test off the battery should be above 10.5V(under load), below 10V the Injector will not fire.
If you don't have A Load Test ,Read the the Battery voltage before Starting and have someone crank the car and read the meter while on crank ,how much it drop that is your load test.
You also can check each cell with and Multimeter. Start with the negative post(black probe to the post ) to the closes cell (red probe to the cell let the probe touch the water, you should get a reading about 1.5 V to 1.75 V next one Check cell to cell
, you should be getting about 2 V each cell and again from the cell to the post about 1.5V to !.75. Total it up you will get 13v to 13.5V . You will find where the short is when you get a reading below what spec,

------------------------------
Bud