Rotarctica

So I think I have a battery drain. I just bought a brand new battery because the last one kicked it. It has 520 cold cranking amps rating or whatever...so needless to say, it cranks with zest. However, when I went out to start it the next day it cranked over pretty quick but not as fast. After driving it to Atlanta and stopping for gas, it cranked over with the same zest as the first time I'd cranked it on that battery. Went out this morning to start it and it cranked over that same not-as-fast speed. So I'm guessing I have a drain somewhere. I wanted to rule out the alternator, so I did some searching. I heard you need to pull the wire off the top of the alternator (Mine's bolted?). And this post is pretty much to clarify that it IS the black on literally on the TOP of the alternator held on by a bolt with a rubber boot over it? Unbolt that, set it somewhere safe and out of the way and see if the next morning, it'll crank with vigor? And if it still cranks slower-than-prefferred, then it ISN'T my alternator...and it's something else...in which case, it might be the end of this particular RX-7. The gas mileage not getting better than 20mpg average is kind of hurting me because I am regularly driving to see someone two hours away.. :-\ If it is my alternator, I think I'll just keep disconnecting the negative battery terminal when I leave the car overnight to avoid this issue until I can afford a new alternator. I can't be dealing with serious electrical issues in my current financial state.

Yep...so it's that wire, right? not the plug thing behind the alternator?

Rotarctica

Something I think I forgot to consider. My headlight switch is apparently on the rag. The running lights and headlights work, but sometimes I have to push on the dimmer control like mad to get the dash/console lights to illuminate. Could that be my drainage problem?

Icemark

series??? Model???

Come on post at least the basics!

And is this the stock alt or???

and the headlight would have nothing to do with it, unless you left the lights on

Rotarctica

Well I do believe the Series and Model are both in my profile, but okay...

1986 GXL and I believe it's the stock alternator. I went ahead and unbolted that damn wire anyway >.<

Icemark

Not sure why you are unbolting what sounds like tha charge wire.

What is the voltage when your car is running at idle? and at idle with the lights on???

Anything under 13.5 volts and you are not charging the battery

Anything under 12.6 volts and you are running on battery power and the alt is not putting out enough juice to even run the car.

I look at 100+ posts a day. If I had to look at everyones profile to figure out what they were driving or talking about; I'd be here 28 hours a day.

Rotarctica

The voltage sits just under the 14 volt mark at idle. When I switch suspension modes, the voltage drops and then goes right back up. The car runs okay, and it's starting. But I had to replace my battery the other day. The other one was from 2001 I believe, and was on it's last leg. It was fine, really, until I started the car to let it warm up and the A/C cool the car off (Full blast) when I came back out ten minutes later the engine was off but the blower was still blasting. It started, but it was kinda slow. So that must've been it for that battery. Replaced the battery, and there's a difference in cranking speed if I let the car sit overnight. If I go and drive it a while, turn it off then back on again it'll crank over really really fast. If I let it sit overnight, it'll crank slower but still adequate. All the while when the car is idling, the voltage never sits anywhere different. Now, it is really cold in the mornings here. Am I being a paranoid git or....what?

All in all, it's pissing me off. I don't want to get rid of the car, but if I run into electrical problems, it's probably the worst kind of problem to have. I only am keeping it because it's in good condition...but if it's going to have electrical problems, it's going to be sold for something a tad more fuel efficient until I can afford maybe a newer RX-7 or bite the bullet and get an RX-8.

About the unbolting the charge wire... I told you, I did some searching on here and someone had suggested to someone else to unbolt that and let the car sit the appropriate time it takes for the drain to occur (In my case, over night) and then bolt it back on and start it. If the problem doesn't occur then you have a bad alternator (So this person said). No one bashed him or argued, so I'm assuming this is a legit test. I'll grab the link in just a mo'.


Edit: Here's the link. It's Wayne's post...
https://www.rx7club.com/showthread.p...=battery+drain

Icemark

Hardley a legit test. I would be surprised if even a lame shade tree mechanic would call that a legit test.

If you are really concerned about a voltage draw, get your multi-meter out, set it for amps and do a current draw test.

There should be between 35mA and 60mA draw with everything off. If the draw exceeds 70mA then you need to start looking at how any aftermarket electronics are wired on the car or what circuit the draw is on.

Edit<After reading waynes posts in there, I even more so can not recommend that. If you want to see if you have a bad rectifer diode, you simple set your multi-meter for AC voltage and meter between the alt charge post and the ground. If you see any AC voltage, then there is at least one bad rectifer diode in the alt.

Rotarctica

So if I do a draw test and it exceeds 70mA then I have a drain on my battery, and if it's within 35-60mA I'm perfectly alright? I know I have the Pioneer head unit. I didn't put that in, the last owner of the car did. And it's been fine. Nothing works out of the ordinary, of course. There's a switch on the right kick panel for the power antenna since the head unit doesn't support such a thing. And there's also a switch next to the front speaker that no longer is connected to anything, that was for when the wiper switch wasn't functioning correctly (He later bought a rebuilt switch). Other then that, I do believe all the wiring is as it should be and I haven't yet had an issue. Maybe I'm being too paranoid about this?

Icemark

Yes. Current draw issues are very easy to fix.

Rotarctica

Not with only $28.00 to your name they're not!