Something is bleeding power from my battery and it only takes a couple of days to killl it... One thing I am thinking is the alternator is somehow pulling power because there is a very small high pitched noise coming from it when everything is off. I have a large 4 gauge wire from it to the starter where the positive from the battery cable is. I also have an 8 gauge wire from the fuse box inside the car to the alternator... Just from reading a few threads, it sounds like i should leave the large wire and connect the fuse block wire to the positive of the battery... Any input on this problem? Thank you in advance
Ya I just read the alternator can also fluctuate your power in your dash so ill wire it to the bat. Just to know for sure, if I tested the wire for current draw would I put one probe on the output stud on the alternator and one on the battery ground terminal?
battery is new but the alternator is a junkyard part... anyone hear of the alternator making a really light noise with the car off?
it doesn't get driven much but if i leave it for just 2 days and try to start it it's dead. i have been trickle charging it lately but i want to cut back on this problem cause its dying faster than it should.
I attached a pretty poorly drawn diagram of what i was trying to say.. yes there are two wires going from the power lug on the alt.
i should have written starter solenoid instead of just starter... Also, this is a 2005 chevy silverado engine with a 145 amp output alternator, that mad electrical is talking about some pretty old systems, idk if that makes a difference...
If the battery is dieing when the car isn't even running, then why do you think it is the way the alternator is wired?
Is your alternator even charging? What voltage is your alternator putting out when the engine is running? Should be over 14 volts.
There is nothing in your wiring diagram that should be causing the battery to go dead with the key off. How are the small wires going to your alternator connected? You used a switched 12V source for the field voltage, right? With the key off there should be zero volts on all the small wires hooked up to the alternator.
Provided the battery is good (new ones can be defective), then chances are you have something drawing current when the car is off.
Get your alternator tested at a parts store. Something might be shorted out. If that doesn't fix it, then you need to start isolating circuits until you find whatever is drawing current. See if you can put an ammeter in the battery line and with the car off measure current. If the meter reads anything more than a few milliamps, start pulling fuses until the current draw drops. That is the circuit where your short is.
And I say again, don't wire your alternator output directly to your battery. There are better ways of doing it. Nothing has changed with the newer alternators. If you want to move a wire, then make the 8 guage wire go from the fuse box to the starter. if you really want to do it right, then put a lug on a fender, make the 4 gauge from the alternator go to that, put a 10 gauge wire with fusible link from the fender lug to the battery, then run another 10 gauge wire from the fender lug to the fuse box. Just keep in mind none of that will fix your dead battery issue. you need to first find out if you battery is being charged when the engine is running and then find the source of the current draw when the motor is off.
Last edited by Pop N Wood; 04-11-2011 at 05:18 PM..
I am getting a good amount of charging from the alternator so my wiring works alright. I read through the mad stuff and he really likes those junction blocks and regulators to keep the voltage at 14.2... I guess technically the starter stud could be like my junction block, but I don't have a regulator there... I am wanting to get my wiring right if there is a problem it would be easier to fix now and that's why I got so off track from the real battery dying issue... I'll check those small wires to the alt too thank you for the tip
You used a switched 12V source for the field voltage, right? With the key off there should be zero volts on all the small wires hooked up to the alternator.
OP, I'm pretty sure this is what your issue is ^^^^
If you can hear a slight wine coming from your alternator when the car (key) is off, you have wired the field wire to a constant 12v source and not a switched 12v source. This WILL constanly draw current, even while the car is off. This wire (that runs to the plug on the alternator) should be wired to a keyed or switched 12v source. Give this is try and see if your battery doesnt' stop draining. Now I'm not saying that other issues that have been raised aren't legitimate, but the above is definately not helping.
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