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Discussion Starter · #1 ·
Hood Motor vehicle Automotive design Automotive exterior Vehicle

Did a bunch of work to my truck, put on new 145amp alternator included in the work, so I went for a test drive and it ran great no issues with charging or anything. Parked it and then wouldn’t start the next day, it wouldn’t turn over fast enough to start in -48. So, I went and bought three new batteries(one in the box on my hydraulic deck). Put the new batteries on, put a battery charger on the truck for a few hours. Then went out and started the truck, let it idle for about 15 minutes. And the alternator was not charging at all, it sat in the bottom 1/4 of the gauge running off the batteries charge.
I checked the red box where the alternator hot wire goes. No corrosion. New batteries had good connections. Alternator was working just prior to the new batteries. The alternator literally has two drives on it.
Took the alternator off, opened the back nothing burnt. Nothing broken. Everything connected. I’m going to take it in to get tested tomorrow morning. But is there anything in the mean time I could be missing? I stuck the battery charger back on 4amp charge overnight to make sure the batteries are completely charged up.
 

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Did a bunch of work to my truck, put on new 145amp alternator included in the work, so I went for a test drive and it ran great no issues with charging or anything. Parked it and then wouldn’t start the next day, it wouldn’t turn over fast enough to start in -48. So, I went and bought three new batteries(one in the box on my hydraulic deck). Put the new batteries on, put a battery charger on the truck for a few hours. Then went out and started the truck, let it idle for about 15 minutes. And the alternator was not charging at all, it sat in the bottom 1/4 of the gauge running off the batteries charge.
I checked the red box where the alternator hot wire goes. No corrosion. New batteries had good connections. Alternator was working just prior to the new batteries. The alternator literally has two drives on it.
Took the alternator off, opened the back nothing burnt. Nothing broken. Everything connected. I’m going to take it in to get tested tomorrow morning. But is there anything in the mean time I could be missing? I stuck the battery charger back on 4amp charge overnight to make sure the batteries are completely charged up.
Please tell us a little more about the truck ( Year, Make, Model ) and list all mods (y)
 

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Discussion Starter · #3 ·
2006 Chevrolet Silverado 2500hd
Ryan’s 64mm turbo, s&s super sport cp3, afe cold air intake, afe hot side intercooler pipe, 3” EGR delete, 3” y bridge, methanol injection, afe 3” downpipe, ppe ported fuel rail fittings, fass titanium lift pump, fass disk heater, NADP race transmission, ATS transmission pan, cognito traction bars, Yukon grizzly locker, magtec diff cover, airlift air bags, zone upper control arms, amsoil remote engine oil filter kit.
 
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Discussion Starter · #4 ·
Alternator tested good at the shop. Guess I’ll have to test the grounding of the alternator bracket. I’m not getting battery light on dash. Had the bracket off when I powdercoated everything. Maybe it’s not grounding.
 

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Just to follow up, took alternator in to get tested. To rule out the new alternator was bad. And it was a functioning alternator.

checked over resistances and noticed that there was some between the alternator body and the battery negative while it was on the truck.

So I took the alternator bracket off, and cleaned up the mating surfaces on the bracket where it meets the block, and where the alternator meets the bracket. I had sandblasted the bracket and then taped off the areas where they mounted but I’m thinking it oxidized or something when it was in the oven. I took a file and make it fresh aluminum and threw it back on and sure enough alternator is charging like it did before.
 
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Just to follow up, took alternator in to get tested. To rule out the new alternator was bad. And it was a functioning alternator.

checked over resistances and noticed that there was some between the alternator body and the battery negative while it was on the truck.

So I took the alternator bracket off, and cleaned up the mating surfaces on the bracket where it meets the block, and where the alternator meets the bracket. I had sandblasted the bracket and then taped off the areas where they mounted but I’m thinking it oxidized or something when it was in the oven. I took a file and make it fresh aluminum and threw it back on and sure enough alternator is charging like it did before.
Sounds like you got the issue resolved.
Thanks for giving us an update!
(y)
 
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