Alternator charging at consistent 14.7 V

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Trevor B

Trevor B

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I have been having alternator problems - can’t get the stock one to charge right.

So… I put in a brand new Tuff Stuff one wire that I was saving for a different car. It has an internal regulator:
LINK

I followed the directions and ran an 8 gauge wire directly to the starter relay. It works, but perhaps too well. I’m reading about 14.7 volts at all RPMs to a brand new battery. This is with no lights on/accessories.

Is this too much? I always thought the voltage should be in the 13.x neighborhood.

Thanks!
 
Sounds good to me. My voltmeter on my 2004 silverado is sitting on 14.3 now. Also has 30 psi oil at 600 rpm idle with 115k miles...:)
 
Nope. It’s as good as you can hope for.
 
I consider 14.7 a perfect number.
 
Okay! Well that's good news. I was afraid to go out on a long drive because I didn't want to fry anything.
 
14.7 is certainly within what I'd call "the range." 15+, something different
 
The proper float voltage for a lead-acid battery is also temperature dependent. (Higher voltage in cold temps, so obviously, lower voltage in hot weather). It's not a huge change, but the nominal 13.8 volts is at 77F. Not only that, wet batteries vs. AGM have different requirements too.

Underhood (or in-trunk) temps vary a lot with ambient temp, sunshine on the hood/trunk, etc.
Charging at High and Low Temperatures

So 14.7 volts at the battery terminals is a little high unless that was measured at near-freezing temps, but won't immediately cause a problem. For an Optima battery it'd be closer to correct.

One more thing - is your voltmeter accurate? Could be several tenths off...
 
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