OK so lately, my battery as been draining overnight. I THINK its a parasitic power draw (yeah?) but I dont know much about cars so im not sure. If I leave the car off for a few days (and now just over night) when I go and try to start it I just hear the engine turn over slowly and nothing really happens.

I tried seeing the amps being drawn from the battery, but when I set my multimeter to mA and connected the probes to the battery, the fuse blew.

Something I found strange was that when I set the multimeter to dc volts (25) and test the battery the needle goes up all the way to 25. Could this mean somethings wrong with the multimeter, or the battery? (I noticed this before I blew the fuse)

So I think its either:
a. the battery is messed up
b. somethings taking power and draining it
c. alternator is messed up

It's a 1988 Nissan Stanza btw. Old car but really good condition, under 120k miles, this is the only problem I've had with it really.

help?

I tried seeing the amps being drawn from the battery, but when I set my multimeter to mA and connected the probes to the battery, the fuse blew.

Hmmm, maybe it's because it's drawing more than 1000 mA? :p Always, always, always use the highest setting if you are unsure of the magnitude that you are measuring, especially for current measurements!

Is it going up to 25V when the car is running? If it's not running and going that high, I would see about what another meter would say. (You DID replace the fuse, right? My meter blew the big 120VAC/20A fuse and it wouldn't work at all for voltage until I jumpered it.)

Lead-acid batteries can only hold a little over 2VDC across each cell. If you apply any higher voltage it just eats up the donor plate, makes a lot of heat, and also dries up the sulphuric acid solution which raises the impedance of the battery (fewer cold cranking amps) and dramatically lowers the capacity.

In your case, either you have a bad battery (if so, I'd check the alternator as well) or you have a big current draw when the car is off.

I had a similar problem recently and it turned out to be the battery going bad. The problem appeared suddenly, but, in the end, replacing the battery fixed it.

regarding your battery:
I'm pretty sure you can't get much more than 13 volts out of an isolated, recently charged 12v battery.
Say you charged it using 16 vdc, when you unhook the charger, the battery will still only read maybe 12.5 vdc.
To me, your meter is questionable.

If you suspect parasitic draw, it will probably be amperes, not milliamps, so to test with a meter, start with a higher meter setting (~10 amps) and work down through the ranges.

If you didn't do step one below, you'll surely get way more than milliamps running through the meter = fuse blow.

from:
http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

Steps to Find-a-Parasitic-Battery-Drain

Step One

Remove the negative side battery cable from the negative battery terminal.

Step two

Attach an ammeter between the negative cable and the negative battery post. wait a few seconds to several minutes for the car to go into sleep mode. i.e. when you make the contact with the test light the cars computer systems "wake up" after a bit of time they will go to "sleep".

If the ammeter is reading over 25-50 milliamps, something is using too much battery power.

Step three

Go to the fuse panel(s) and remove fuses, one at a time. Pull the main fuses (higher amp ratings)last.
Be sure to observe the ammeter after pulling each fuse.

Watch for the ammeter to drop to acceptable drain. The fuse that reduces the drain is the draw.
Consult the owners' manual or service manual to find what circuits are on that fuse.

Check each device (circuit) on that fuse. Stop each lamp, heater, etc. to find the drain.




+++++++++++++++

Here's another method that removes the positive battery cable ... from:
http://www.ehow.com/how_2249402_find-parasitic-battery-drain.html

Steps

1 Step One

Charge your battery if necessary. Dead batteries (and even weak ones) don’t give accurate results on a draw test. The dome light is a good indicator of battery strength. If the light is weak, pulsating or refuses to turn on, you’ll need to charge the battery.

2 Step Two

Shut off everything in the car. Pull the keys out of the ignition. Ensure all service lights are off, lighted compartments closed and doors shut. Open the hood, and disconnect the trouble light underneath if your vehicle has one. Wait for 30 minutes before moving on to Step 3. (This enables normal drain from interior components to finish cycling.)

3 Step Three

Set your battery tester to 10 amps DC. Disconnect your positive battery connection (red cable) and position it safely away from metal components. Connect the meter’s positive probe to the battery’s positive post while simultaneously holding the negative probe in the air; keep it away from anything metal.

4 Step Four

Place the negative probe on the end of the removed positive cable to complete the circuit. Yes, you’re putting a negative on a positive. Yes, this is ok. If you have a severe drain, you’re likely to pop a fuse or two—identifying your problem.

5 Step Five

Check the meter reading. A normal reading is usually under .035 amps. If you have a minor drain that causes a higher reading, you’ll need to check each component.

6 Step Six

Remove the first fuse in the box, and check to see if the load problem is resolved. If not, replace the fuse and check the next one. Repeat the process with all fuses. If the fuses check out fine, you have a wiring problem.

7Step Seven

Remove the tester and reconnect the battery. Follow the hot wire to the next connection. Remove the positive cable and connect the positive probe of the tester in its place. Connect the negative probe to a metal object. Check the meter. If the drain isn’t resolved, reconnect as normal and follow the hot wire to the next connection. Repeat this step at each connection point until you narrow down the problem.

Tips & Warnings

Never use a tester with less than 10 amps DC. Connection to a car battery will give inaccurate results and can destroy the tester.


edit:

I see I'm repeating alot of what AP2k wrote while I was making my post.

So I tested between the negative battery post and cable, and everything seemed normal except the needle would occasionally jump and I'd hear a noise. Turns out that was my auto antenna trying (and failing) to come out. I unplugged the cable harness for that, cutting the power off.
So I guess I'll know after leaving it off for a while if thats actually what it was.
Thanks for the help.