gauges work only when revving

I've seen this with "high output alternators" that are rebuilt. Simply put your alternator does NOT charge at idle speeds. (700 RPMS). But will charge at higher RPMs. (1200 or higher) Test it with your DMM, You will see that at high rpm your alternator will charge fine.

So what's the solution? Get a smaller Alternator Pulley. (The end piece where the engine belt runs) This will get the alternator to spin faster at idle speeds.

... and hopefully not too fast! (In old days, rally cars had to increase the size of the pulley because alternators were not designed to be run constantly at high RPM.) It seems the rebuilds are less windings of a thicker wire... Pity - I have been impressed how stock 20 year old alternators supply 14.4V at idle speeds with high beams etc. Mine is only a 75A unit and the battery charges at over 40A after cranking. So much for modern Y-Delta (etc) switching stators.

u know what i could be wrong i tried again today.. i changed ALL my grounds i even added another! i even scraped to bare metal when i put the contacts on.. still didnt crank im going to charge my battery at 10amps for about 6-12 hours on 10amps and see how that goes.. ill keep u guys posted thx

well tomorrow im gonna charge up the battery and see what happens and take it accordingly i will keep u guys posted! thanks for your input everyone!

k gentlemen i boosted my car

everything was fine

the voltage at the battery was 14V to begin with then fluctuated around 12.6 V

same with the alternator..

then out of no where.. the voltage on the alternator started to decrease!! im talking around 11volts

and then i measured the battery same thing!

does this mean the battery is crap? or the 160A alternator i put in is crap?

or should i just charge my deep cycle battery fully and see what happens??

thx guys

alright

i checked the voltage across the battery now its 12.36V

im charging it at 2A right now

and hopefully this will fix my issue

come on optimaaaaa

Once the alternator cools down it'll charge again. Change your alternator. IF it was refurbished, check out IRAGGE alternators. I know they''re not cheap, but its worth the money considering its ganna work right.

i just changed the alternator!!!!!!!!!!!!to 160A! iragge? im gonna see if anyone in Toronto Ontario carries them. thx guys

Your battery should be ~12.7V fully charged, but it should not drop (by itself) to 12.4V etc. If it does, it is stuffed else has some load connected. Good batteries will usually be ~13.6V after charging due to surface charge. That should take hours - else minutes under load - to drop to ~12.7V. And with the engine running & charging, the battery should way exceed 12.7V! Geez - even my 40 year old alternators put out more than 13V at idle! Alternators should output 13.8V to (max longterm of) 14.4V. But check you battery. I have seen alternators use their entire capacity trying to charge a faulty battery. (That's before the battery explosion or fire...)