Many new and rebuilt alternators come with a tag that you have to remove before you install them. They tell you to fully charge the battery before you run the car. If you don't, you can overload the alternator. They are not designed to charge a low battery.

 

so in scott case, both are bad at the same time? know his alternator is not that old.
Scott should install a voltage gauge

 

No, Ron. I think it would be jumping the gun a bit at this point to say that (about the alternator I mean). I think it's conjecture to even say that he has a bad battery, but it would seem that way until it can be confirmed good, then more tests should be run. A voltmeter is not a bad idea. I always wondered why Porsche didn't install one to begin with.

 

Because they wanted you to know what time it was instead ? I put mine in and it is one of my most watched guages.

 

Scottb,
I am in search for the best solution for my case too so please post if you have any solution/status.
Thanks Scott.

 

I haven't had a chance to deal with it. Maybe over the weekend...

 

Ok, finally I got some times to run to Harbor Freight for a new multimeter and start my measurement, again.
The car was driven for about 1/2 hour, then parked for another 1/2 hour before the measurement at the battery begine. Engine off, key off, all doors closed and nothing is running except the stock clock.

V: 12.83v (hood light on)
current: 76ma (hood light on, alarm armed) pic1 below
current: 50ma (hoodlight off, alarm un-armed) pic2 below
Current: 20ma (hoodlight off, alarm fuse pulled = disconnected) pic3 below.
Pledase verify the way I read currents.

4 hours later, just before I posted this result, I went to the car and did measurement on voltage at the battery again. Look like I lost around 0.2v in around 4 hours, without alarm conected:
V: 12.63 (hoodlight on)
V: 12.68 (hoodlight off).

I think it doesn't look like my car is draining too much power, but why my batteries died too soon, and I need to jump start every 2 weeks or 10 days, sometimes even in 5 or 6 days. Note: my voltage analog gauge showed around 14.9v at freeway highspeed.
I will connect the digital multimeter tomorrow to read the digital number while driving. Maybe my eyes are not good at the analog neddle, I hope. Otherwise, my alternator needs redo, right?

Added: can't sleep, I came out and measure my 8 year old Lexus. It is similar to my Porsche, with alarm disconnected (30ma). So maybe 56ma makes that much different huh, with alarm armed. Can someone tell me how much current your alarm takes?

hood light on, alarm armed (76ma)


hoodlight off, alarm un-armed (50ma)


hoodlight off, alarm fuse pulled = disconnected (20ma)

 

I draw about 15ma and I don't have a factory or aftermarket alarm.

How about just leaving your alarm fuse out for a few weeks and see if that is causing your drain ?

Your current sounds plausable so you must me connecting to the amp and ground, disconnecting the battery cable and putting it between. This way the current runs THROUGH the meter. This is the correct way.

at my measly 10-15ma draw the battery will last about 2 weeks with my interstate. if it is longer I put my trickle on anyway so I don't know if it could go longer.

YOu may also want to check your stereo sytem if i is aftermarket and make sure your amps aren't being powered with the ignition off.

 

PS for a more accurate reading you can move your lead down to the lower onnection. It will give you readings in the milliamps which is what you really want.

 

would he find draw at the fuse blocks? I need to see how much draw mine has. I'll check later tonight.

 

Then the meter won't work. It sit there and won't move.

 

you have to move the dial to the correct range. It should work , but regardles . i think you have the right idea.
Rusnak to check total current drain on the system disconect a battery lead and put the meter between themonce the current flows through the meter you will have total drin for the sytem.
Removing a fuse and replacing it with the meter will do essentially the same thing for each subsystem as the current instead of flowing through the fuse will flow through the meter.

 

Hi Ice,

Yes I was going to do that with my good meter when I get home tonight. I have a crappy one in the trunk for emergency only use.

I was thinking that he might have something wrong in one of the systems, and therefore be able to trace it.

But 50 ma is nothing. It shouldn't drain the battery.

14.9 v charging is almost overcharging,
and 12.83 with almost no load suggests that the battery is weak.

I think the focus should probably be on the battery - i.e. check fluid level, charge with a good battery charger for a day, let it rest for a half an hour, put a starter load on it, let it rest, then test it again under load. My guess is that the battery will be shown to be weak.

 

+++++1

Doyle

 

end of the day throw a smart charger on a good battery and you can go for years. Will significantly extend the life of your alternator too as it hardly ever has to top off.