Alternator only pushing 10.4 volts....

okay so i was out at Glamis California and i was driving around in the dunes... my truck bogs down. there's a brand new 160 amp high output alternator (re manufactured) in there. so i throw in another battery just to get me back to camp.

so i pull out a ohmmeter and test the volts coming out of the alternator. it says about 10.4 volts. now i know this isnt right, because its supposed to push out 14.4 volts give or take .5.

so i call the place where i got my 160 amp high output alternator and they send me out another one.

so i put this one in and i take it down to o Reilly and they say its still pushing 10.4 volts.... the new one i just got!! so i called my friend and he said sometimes with the high amperage alternators the volts will be low at idle but higher when not at idle. but the store is closed now and i don't have my ohmmeter handy..... couldn't be a fuse since its still somewhat working.... or ground cause its somewhat working... any ideas??

my truck hasn't bogged down yet with this alternator but i have only driven it 20 miles.

thanks in advance

 

and i want being very nice to my truck that weekend either if that matters

 

i have one of those...its full on at like 750rpm for me

 

dang okay thanks.

any idea on what it could be??

 

its not my wiring either cause we just used a ohmmeter and bypassed all the wiring (straight from alternator to the negative) and its still putting out under 11 volts.

i went through my stock one, a remanufactured one, and a brand new one. so it cant be the alternator its self...

 

how did you test it?

 

just got done walking home in the pouring rain. only a mile though

dam alternator!!

 

No excitation current at the field wire?

 

How do you have it wired? What gauge wires did you run? Big 3?

 

when i hook up a test light it lights up, i dont have an ohmmeter at the moment....

im running all the stock stuff. i was tired last night when i typed this my story was wrong. my stock alternator stopped working, put in the high amp one and it still wasnt working (i didnt even drive with the high amp one) now i have this new one.

so what ever happened happened when the stock alternator was in it.

just went to o reillys and they tested the second alternator (1st high amp one) and its pushing 14.7 volts, when on the truck it only pushed 10.4 volts. even with the wires disconnected testing it directly form the alternator to the negative on the battery it still pushed the same. and when your alternator works you should be able to pull the positive off of the battery and it should stil run, it doesnt.

 

With your high amp alternator you definitely need to upgrade the wiring from the alternator to the battery and I would suggest the big 3. Those wires will burn up real quick if you drive with that high amp. As chris4x4 said there is a grounding issue and rewiring will allow you to get a fresh clean ground.

 

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okay so i checked my 80 amp alternator fuse. its good right? then i check all my fuses inside of my truck and there was a 10 amp fuse blown that doesnt let my dash work. replaced that baby and now im at 14.5 volts!!!!

ill be upgrading my wiring also

 

i hate wiring. i went through about 20 fuses last night lol

 

im right there with you. I SUCK at wiring and troubleshooting electronics....effing nightmare.

My dad worked for 15 years as an aerospace electronics tech and troubleshooter....guess it just never rubbed off on me