Power Draw? From where?

Greg5OH

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Hi guys, few months ago i replaced my alternator because it took a crap with a unit from oreileys w/lifetime warranty. Everything was dandy, however my voltage gauge would flicker sometimes. Last time i drove the truck was 4 days ago, i go to crank this morning and it will barely spin over. Before those 4 days it was another 3 days before i drove it but it fired fine then. Batteries are 4 month of jkirkland, new alternator and recent voltage regulator. (this is my 91 truck btw).
Seems i have a power draw somewhere, or the alternator quit charging. I haven't ran any tests yet.
All battery cables are new, doubled up 00 awg. The ONLY wire i havent replaced is the 8 awg one running from alternator to battery. Could that be the culprit, and its simply not charging my batteries? How can I check where(if) I have a drain?

Thanks.
 

laserjock

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You can check for a drain if you have an ammeter. You put it in line with the negative side of the battery to your neg battery cable. If you do that make sure that you run a jumper wire from the negative cable to the negative battery post before you insert the meter in parallel. You can get a spike if you just insert the meter and blow the meter up. Once the meter is in line, pull the jumper off and check the current. On a 91 unless you have something fancy, you should only be showing I would guess at most 50-100 mAmps because essentially all you have is the radio. If you find something, I'd start by pulling the charge wire off the alternator, then unhook the voltage regulator, then maybe the GP controller. From there, start through the fuse panel. Pull them one at a time. That would help you figure out what circuit the draw is on.

Hope that helps.
 

junk

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What laserjock said for checking a draw. I just checked this myself on a rig. I would also pull all the cables off the fender mounted starter solenoid and clean them. Mine were pretty gunky.

Ericthecarguy on Youtube has some good trouble shooting videos also.
 

Greg5OH

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thanks, i shall try that. I dont even have a radio! lol.

I got one of those clamp type ammeters. Ill try that first to confirm if there is a draw. If there isnt, safe to assume the batteries aretn getting charged. Will report back.
 

laserjock

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Amp clamp may not be sensitive enough to see it depending on how big it is and what type of amp clamp it is.
 

Greg5OH

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its a smaller one, the one witha fixed fork, not the huge one that claws open up.
shows to 3 decimal places.
 

FarmerFrank

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I just had this problem on my 86. With the engine off, see if the back of the alternator is magnetized. I Just set a wrench against it and it stuck there.

My regulator was bad and keeping the alternator on therefor draining the batteries.
 

Greg5OH

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them regulators i tell ya. I had one last not even 6 months before. This one is about a year old...Hate how the market is flooded with crap. It was an OEM one too!
 

icanfixall

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If the wrench sticks to the back of the alternator then you have a bad doide in the bridge. It might be a bad regulater but usually its the alternator gone bad. I recall you have a lifetime warranty type so take it back and have them test it.. If they know how.. Hope they do.. I went to O'reilly's with a battery that was barely 1 year old for my 79 chevy truck. They tried to tell me I needed a BIG charger to charge it properly..:Whatever::idiot::drunk: So I let them charge it over nite... Next day they gave me another battery. Said it ws bad... Gosh... I wonder what happened at shift change. Some smart guy came in...:dunno
 

laserjock

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One reason mine is getting a 3G upgrade. ;Sweet

I think I found a direct bolt in even with the dual V belt pully already installed. Have to try it and I'll report eventually. :D
 

franklin2

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The easiest way it to put a testlight in series with the negative battery cable. If the testlight lights up bright, you have a drain. You do need to take the other battery loose on a diesel truck with dual batteries. The ammeter will work also, but there becomes some confusion as to what is a good number and what is not. You will always get something on a modern vehicle.

But you said in your first post you haven't checked anything yet. I would check the voltage on the battery with the truck off, and then with the truck running first.
 

helidiesel

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The easiest way it to put a testlight in series with the negative battery cable. If the testlight lights up bright, you have a drain. You do need to take the other battery loose on a diesel truck with dual batteries. The ammeter will work also, but there becomes some confusion as to what is a good number and what is not. You will always get something on a modern vehicle.

But you said in your first post you haven't checked anything yet. I would check the voltage on the battery with the truck off, and then with the truck running first.

The link posted above is a much better way of troubleshooting than the test light
 

helidiesel

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But you said in your first post you haven't checked anything yet. I would check the voltage on the battery with the truck off, and then with the truck running first.[/QUOTE]

Voltage with truck running is just going to be alternator out put at said rpm.
 

Ruger_556

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Amp clamp may not be sensitive enough to see it depending on how big it is and what type of amp clamp it is.

Incorrect... A good amp clamp (Like a Midtronics) will pick up a parasitic draw easily. 50mA is what's usually considered max for "normal draw" and an amp clamp will get you within 10-20mA of an inline meter at that range.

Hi guys, few months ago i replaced my alternator because it took a crap with a unit from oreileys w/lifetime warranty. Everything was dandy, however my voltage gauge would flicker sometimes. Last time i drove the truck was 4 days ago, i go to crank this morning and it will barely spin over. Before those 4 days it was another 3 days before i drove it but it fired fine then. Batteries are 4 month of jkirkland, new alternator and recent voltage regulator. (this is my 91 truck btw).
Seems i have a power draw somewhere, or the alternator quit charging. I haven't ran any tests yet.
All battery cables are new, doubled up 00 awg. The ONLY wire i havent replaced is the 8 awg one running from alternator to battery. Could that be the culprit, and its simply not charging my batteries? How can I check where(if) I have a drain?

Thanks.

Put your hand on the alternator with the truck off. If it is hot replace it as it is drawing your batteries down. There is a test you can do with it running for that but I forget how to do it. It may charge "fine" while still having this problem though so keep that in mind...

If it's not the alternator drawing them down and you're sure you have a parasitic draw go into the fuse box and check for a voltage drop across fuse pins (The nubs on the back). If there is current flowing through the fuse there will be a slight voltage drop across it.

But before doing any of this test your batteries!
 
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