Thanks for the info gernby. I'll have to talk to some of my friends at work and see if anyone has an ammeter. If I can find an ammeter, do I just measure the current across the battery?

 

No, it was a replacement battery from Honda. They replaced the battery a couple of months back when I noticed that mine constantly said that it needed charging.

 

Yet another update:
Last night I measured the current draw with the car off. With the alarm hooked up and the alarm off, the car was drawing 0.20A With the alarm connections removed, the draw from the battery reduced to 0.18A. As a comparison, I had my friend check his current draw on his WRX, and it was only pulling 0.03A???
This is really confusing me, as I figured that the alarm would be the part of the car that would be drawing the majority of the current. My only other modification I have made is an aftermarket stereo, which I am going to disconnect this afternoon to see what the current draw is without the stereo or the alarm hooked up.

Has anyone measured the current draw of their S2000 with the car off before? If not, could someone do that for me, as I would like to get an idea of what amount of draw I should expect from our cars, and whether or not my car needs to be taken into be serviced.

 

I don't know what the normal draw is on a stock S2000 but I think it's a pretty safe guess to say it would be in the mAmps (no more than about 50). Your alarm is drawing 20 mA - don't see a problem here. I'm thinking it's your stereo mod and the way it is wired in. Do you have a separate amplifier? Maybe it's hot all the time. It shouldn't take more than a few mAmps to keep the memory for the HU or a CD changer.
Sorry, I don't have time to do an amp measurement for you. Hopefully, someone will just know this info and come forward.

 

Well, the stereo is just a plain old Sony deck. I don't have an external amp hooked up. I do have S2kman's (I think that's who it is) Sony DCU hooked up, but besides that it's just the deck. When I turn off the car, the stereo turns off (except for the memory power), so I'm not sure how it would be drwaing the current, but hopefully I will find out after work today.

 

Well, I did more troubleshooting last night. When I unhook the alarm, and the stereo, the current is reading at 10mA. After that I plugged in the alarm, and that reading went up to 30mA. Then when I plug in the stereo as well, the current jumps to .24A. But for some reason I held the connections longer than I did before, and after about 10 seconds, the current goes from .23-.24A to .04A (40mA)!!!
So now I guess the problem goes back to my battery again! I'm figuring that I have a bad cell or something, which is why my batterys voltage keeps dropping at a slow rate (.25-.5V per day).

 

Here is a idea, try measuring the current while you pull the different fuses. Hopefully you can find what circuit the major pull is on.

Also you can go to AutoZone or other parts store and get the battery test while it is in the car. This should tell if you have a bad cell or not.

I don't know if this is true or not, but I was told that the batteries used in the S2000 are not an every day battery. They are gel batteries. I have friends who have these in their Acura's and they have lasted for up to 7 years.

If a battery, any battery is losing it charge after a couple of days, then the battery is bad or there is too much of a drain. I have a old Triumph sports car that will set in the garage for a week or two and will still start.

 

[QUOTE]Originally posted by AirWolf
[B]Well, I did more troubleshooting last night. When I unhook the alarm, and the stereo,

 

Have you tried to measure the voltage with the car running? It should read between 13.8V and 14.2V. If it is below this, your alternator is probably not charging the battery and is defective.

 

Man electrical problems drive me nuts!

Yes, I measured the voltage when the car was rinning, and it was sitting at 14.3V, so the alternator isn't the problem.

I'm planning on getting my battery tested in the morning, and hopefully I can finally get some answers on this problem.