Just installed 3g alt....voltage does not exceed 13.8x ?

[blk92stangg]

Just installed a remanufactured 3g alt off of ebay. I read all the how to's, and installed it with 4 gauge cable, orange wires unconnected, 175 amp fuse inline on the 4ga cable. My question is this:

Voltage across the battery terminals at start up exceeds 14 volts. But after a short jaunt around the block with all the accessories running, the voltage pegs at 13.90ish volts. It doesn't matter if I goose the engine, keep it steady at 2000rpm, etc. I have the general understanding that the voltage is ultimately determined by the alternator regulator, so is it OK that the voltage is so low? I have read a bunch of posts and web pages calling for 14+ volts at higher revs, but I have yet to find a good answer that satisfies me. Also, the 3g has the larger pulley on it, but once again, would that really matter? I am somewhat comforted with the fact that since the voltage is staying well above 13v with all accessories on-ac on high/lights on/hazards flashing/etc, the alternator is able to put out the amps needed to keep the battery charged (I assume). SO, does anyone opinion on the minimum voltage the alt should be putting out? Is the regulator on its way out? Or am I just fretting over nothing? Thanks in advance.

 

[timewarped1972]

most vehicles i have ever put a volt meter on when running go between 13.6 and 14.2.........with about 13.8 bein the norm. it's a 12 volt system, could be your alternator just doesnt happen to be one that belts out 14 or more.......if it's perfectly steady at 13.8 i would'nt stress on it......wish i had a 3g so i could go with an electric fan.......someday.........if it bothers you that much go buy a new one and send your 13.8 3g to me.....lol

 

[HISSIN50]

i dont have firsthand experience, but ill toss out some thoughts. to me, you hit the head on the nail with the observations that it maintains good output with many accessories on (where the ol' 2G falls on its face).

is your battery pretty topped off to start with? you probably arent needing to be putting a lot of juice back into it. i would bet that if the battery discharged at some point, your new 3G would belt out some good voltage.

my two cents. congrats on the upgrade.

 

[stangbear427]

My 3G runs right at 13.8, and if all the accessories are on it drops down to 12.8. It isn't enough, but I have major problems in my headlight wiring and a thirsty stereo. I had a faster pulley made for it too.
If it stays above 13 even at idle with everything on, you're golden. You don't need it to be cranking out more juice than you can use, it's more important that it isn't putting out less than that it has plenty to spare. Worst case scenario, the 3G can be spun up to a 200 amp relatively easly- that's my next step, since mine isn't keeping up very well.

 

[jrichker]

Alternator voltage output is dependant on two things: load and temperature.

The 3G will keep up with the electrical load unless you have a monster stereo system running, so load is not a factor for most cars. There is enough reserve power for 600-720 watts continuous RMS output with everything running. Most stereo systems only peak at levels above that for a few seconds at a time.

The temperature will cause the alternator voltage to rise when it is cold and drop when it is hot. This keeps the battery over charging and from boiling out the electrolyte. If you have 13.8 volts with a normal or full load, that is very good & plenty of voltage to insure that the battery stays charged properly.

 

[blk92stangg]

Thanks guys! I was pretty happy to come home today and find info posted from you guys, as I value your input greatly.

 

[Rerun]

Mine was about the same voltage when I had my underdrive pullies on, now that I went back to stock pullies it has upped a bit.