My c4 battery keeps draining itself, even after new optima red top install, so I hooked it up to a cheap mastercraft multimeter inline at the negative terminal.

At the 10A setting it reads - 0.02 (sometimes - 0.03 for a brief second).
So I started pulling out the fuses, and the first one (Manual reads: Courtesy Lights, Antenna, BOSE Speakers, AC.) was the only one that made a difference, dropping it down to - 0.01.
All the fuses out (Including the four under the dash on passenger side.) and it still reads - 0.01...

Is there something wrong with my multimeter? Shouldn't those numbers be normal drains (Again, set to 10A)? I tried but can't get a reading on any other setting.

 

Is your alternator working correct? Is it charging at the correct rate? If it charges low then the car needs your battery to keep running. If it charges high then it burns out batteries.

I only bring this up because if you are correct that the multi-meter is reporting correct values and you are connecting everything the way that it should then there may be another reason for a dead battery.

 

How can I test it? With the multimeter?
Also how do I test the battery?

And still, even if those drain numbers are normal why is it that the first fuse drops it down to 0.01?

 

There is a positive and negative plug (I am working from memory so I hope that I am thinking of the correct car) on the alternator. Put the leads into the red and black ones while the car is running. Make sure you have the multi-meter set to above 12v DC. It should read just over 14volts. If not then it is charging low. If it is high 14s or more then it is charging too high.

Battery voltage can be checked with the multimeter. Set it to DC and see what you get when connecting to it.

Do you have a CTEK charger for your Optima battery? If not then a standard charger won't charge it properly.

 

My first question would be how long is it taking the battery to drain?? Overnight, a day, a week?? Second most multi meters have milliamp scales. If you are not getting a reading on one of these I would suspect the meter.. You can check the alternator and battery by using the DC volts scale and connecting to neg. and pos. If the alternator is charging you should read roughly 13- 14 volts with the car idling. If charged between 12 and 13 volts..

 

There are several systems that are "on" all the time: ECM, radio and electronic A/C controller. They need to stay powered so they remember their settings, so you will always see a small current drain at all times.

The ECM has a fusible link directly to the battery (actually it goes through the ECM reset connector, which you can open if you want to eliminate it). The radio and A/C are powered by the CTSY/CLK fuse.

I have heard of messed up power antennas causing a current drain. Sometimes the courtesy lights don't go out because the door switches are stuck or the courtesy light delay module is bad.

 

Ok, so...

I went to check it again (Door switch taped of course), attached the multimeter, and here's the result (same as before obviously):


That's 2 milliamps right? (Set to 10A)

So I go and pull out the first fuse:

(Like I said, its the only one that makes a difference, even with all the fuses, including 4 under dash, pulled at the same time.)

And it drops down to this:


I was assuming, after reading Cliff Harris's post above^, that it was the "always on" systems related to that fuse (Digital AC). But after taking a look at the antenna (Same fuse) I remembered this:

Previous owner had an 8-CD changer installed (Who knows how long ago) which I removed. The two wires that don't go anywhere were already like that before I took it out.
So now I assume it's both the antenna (Problem) and the AC (Normal).
But I can't tell unless I get a more precise multimeter since it's already at its best, and disconnecting the antenna won't register anything since it's less than 0.01 draining.

The antenna and radio works fine by the way, just the rear speakers don't but that's another story.

I also assume the other 0.01 my multimeter shows after taking all fuses out is the ECM then.

Still... 0.02 shouldn't be out of the ordinary, am I right? (Oh yeah, car takes 3+ days to fully discharge. Always less than a week.)

So I'm going to do what 1986coupe and ccrazor said, and check the battery/alternator. If there doesn't seem to be a problem I'll go get a new multimeter and do it all over again.

Oh and, almost forgot, my charger is this one: http://www.canadiantire.ca/AST/brows....jsp?locale=en

 

If you have your meter in series with the battery you are then measuring the battery current or drain with everything off. Most FSMs say (and I am being general for many years) that less than 50 ma (0.050 amps) is an acceptable current. My 94 measures just under 30 ma and I can leave the car for 2 weeks easy with no problems. Most of the current readings I have heard of are between 20 - 30 ma.

With your meter in the picture indicating 0.02 on the 10 amp scale indicates 20 ma which is a great reading and should pose no problem, well within spec.

Also, on many meters you have to use the 10A scale to get the current reading and a lower scale won't work. The higher scale has a lower shunt resistance (meter) which the car needs to active the systems (this is a basic brief description). This is not uncommon as I have to do it also.

As asked, how long until the battery goes dead?

All being equal if you are doing the measurement correctly I don’t see a problem. You already have low current so it seems like you are chasing a problem that is not there. You have missed something along the way but until you provide more exact details on your problem it's hard to give any valid advice or direction.

And also, how old is the battery, is it brand new? As you know anything can be bad and age is not always the single factor.

 

3 days to a week tops to fully discharge.

I'm thinking the battery is bad then, I tried really hard to find a parasitic drain but no luck ( Or should I say luckily)
I just put the voltmeter to 20V scale and the battery read 11.65V or 11.85V can't remember which of the 2, battery is being charged now so I can't get another reading to make sure...Definitely below 11.9V.
Battery is an Optima red top, about a year old now, but it started giving problems as soon as I put it on last summer.

 

OK, so I hooked the multimeter (20V setting) to the battery's terminals, and got lower than 12V readings, then I started the car and to my surprise the numbers didn't change AT ALL! that means my alternator isn't working at all right? I'm suspecting both the battery and alternator are bad.

Could a bad alternator have caused the battery to go bad also?

 

Sounds like the alternator is not charging. When you start the engine, the voltage should be about 14 volts. Depending on how much charge the battery has it should be about 13.5-14.5 and at a very minimum it should be 13.5 volts.

If the alternator is not charging, then you are running on the battery only and over time it will obviously discharge and eventually not be able to start the engine.

The alternator is pretty easy to take out. I probably would pull it and get it checked. Might be the easiest and most productive effort.

 

Problem is, the battery runs down during the week without me even touching the car in just 3+ days. So It seems the battery is also faulty...
Tomorrow I'm taking the battery to be tested, should I bring the alternator to them too? Can they test it if it's not hooked up to the car?

Thanks a lot guys I really appreciate your help. All of you.

 

Considering from what you said in regard to the charging voltage, I would get the alternator checked also so you know where you are. The more information the better and takes the guess work out of it. You might have 2 different items causing these problems.

Places like AutoZone can do a load test on the battery. It's not a bad test, I think it has pretty good results as I have used it also.

 

Can they test the alternator if I take it to them though?
I'm in Calgary, Canada...

Don't think autozone is in Canada...
Maybe Can Tire or NAPA...

 

Check the voltage at the alternator (engine running of course) on the big red wire. You might have a bad/blown connection between the alternator and battery.

I think most big chain auto parts stores have a tester that can check an alternator off the car. I know they do at AutoZone and Kragen/O'Reilly's.

Related story: recently I saw the red light come on and the voltmeter on the instrument cluster was showing 11.4 volts. I made several stops and sometimes it charged OK and sometimes it didn't. When I got home I tapped on the alternator with a hammer and it started working. I figured it was a bad connection inside. I took it apart and cleaned it. Didn't see any problems so I put it back together and it has worked fine since then.

 

Check with Napa, they should be able to test both the battery and alternator for you..

 

My guess is your alternator was the initial problem, but because you've discharged the battery then recharged it numerous times, you've probably have turn the battery into toast. Car batteries (unlike cell phone batteries) are not designed for full cycle discharges/recharges. As the alternator was going the battery was having to work harder to supplement the cars electrics and this also shorten the life of the battery.

The reading of 0.02A is fine, the car generally draws between 0.02A to 0.05A when the car is not running.

 

The battery is being tested at can tire now, should be done in about an hour, I'm taking the alternator to be tested when I go to pick it up. NAPA is closed right now, I'll try princess auto.

Battery took 3 days to discharge from the beginning so I think it was a bad one from the beginning. Unfortunately the place I bought it from closed at 6 so I'll take it there to be replaced if it's tested bad.

 

Did you also pull the circuit breakers? I had a short in my power seat wiring that was draining my battery overnight. The breakers trip whey they get hot and automatically reset when they cool off. I had to leave my meter in the circuit for about 10 minutes before I caught it.

 

Depends on the scale but .020 is 20 milliamps--not 2.

20 is a bit high.