Alt, batt or volt reg problem?
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Elder User
Joined: Nov 2005
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From: San Antonio, TX
Alt, batt or volt reg problem?
I was just driving home, listening to my music in the dark when my bass suddenly cuts out, although the power light on the amp was still on and my head unit was still playing music (I have a 400w amp for my sub). I also notice that my lights are suddenly brighter and the DC guage is pointing slightly towards charge. It's dark out so I'm going to poke around tomorrow morning, but I wanted to see if anyone knew off hand what the problem could be? I popped the hood and didn't see anything obviously wrong (no burnt wires or exploded battery that I could see, but it was too dark to tell for sure). Did my battery or alternator crap out?
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From: Virginia
The first thing you need to do is measure the voltage at the battery terminals with the truck off, and then with the truck running. This will tell you a lot about what's going on. Write back in with your results.
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That sounds more like a amp problem than a truck prob...the gage said it was charging..does it seem to start ok??the lights were brighter because the amp was not drawing on the battery..pulling that many amps you may need to upsize the altanator like one from a police car..good luck bill
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Elder User
Joined: Nov 2005
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From: San Antonio, TX
Thanks for the help. Apparently it was the voltage regulator. It wore out and was charging no matter what, bringing the voltage up to 18v when the engine was running. With the engine off, I was getting 12.9v from the batt. The amp shut off because the voltage was too high (it worked fine when the engine was off and was just drawing from the battery). Replaced the volt reg and everything is working now.
The amp isn't crazy, 400 watts, and the 60 amp alt puts out plenty for that. I just hope this new 'Wells' volt reg from Advanced Auto isn't crud that I'll have to replace in 3 months.
The amp isn't crazy, 400 watts, and the 60 amp alt puts out plenty for that. I just hope this new 'Wells' volt reg from Advanced Auto isn't crud that I'll have to replace in 3 months.
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400 watts on top of what ever else it has to run sounds like your pushing the 60amp alt. to the limet..maybe some one with a calculator could figure out the load for you..I get to s.a. sometimes maybe we can bump in to each other take care bill
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From: Virginia
Power= volts X amps
400w=approx 12v X ?
?= approx 33 amps.
It may be a little more because of loss in the amp from heat, etc. but the good thing is music is a bunch of peaks, so the average will work out to be a little less. That's why they use those large "stiffening" capacitors. They hold just enough to contribute during the peak music demands.
400w=approx 12v X ?
?= approx 33 amps.
It may be a little more because of loss in the amp from heat, etc. but the good thing is music is a bunch of peaks, so the average will work out to be a little less. That's why they use those large "stiffening" capacitors. They hold just enough to contribute during the peak music demands.
