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Alternator output voltage

 
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Porver9two4  



Joined: 23 Jan 2004
Posts: 100
Location: United Kingdom

PostPosted: Thu Dec 07, 2017 2:26 am    Post subject: Alternator output voltage Reply with quote

Does anyone know what the standard alternator output in Volts is for a 2.0 NA? I know the alternator is rated at 75 Amps and would assume it should be producing between 13 and 14.5V, but mine seems to be reading low....
At first I suspected the gauge, but having now had a meter on it I am only getting about 13.2V with no load and that drops to a measly 12.3 with the lights and blower on. I can't believe that is right and suspect I may have an issue brewing..... finding the issue may be more of a challenge though as the alternator appears to be working correctly, just producing low volts.
It has just had a new starter motor / alternator wiring loom as the old one was completely and utterly corroded to death, so I know that part of the wiring is sound.
Could it be an earthing issue? I can't recall where the main engine earth is off the top of my head....
The alternator is a Bosch 035903015M / 0120469551.
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nikobbell  



Joined: 29 Nov 2017
Posts: 4
Location: chicago, illinois

PostPosted: Thu Dec 07, 2017 6:34 am    Post subject: Reply with quote

not sure about standard output. I had the same problem and took the alternator out and had it tested. Major pain. It was fine. So I just ran another ground from the back of the alternator to a bolt on the shock tower and voila.. it's throwing 13.83 at idle. Around 132 with lights and blower on. The ground may be your problem. Check your belt too, may be slipping if it's old and worn. since I had it out i changed the rubber bushing that mounts the alternator to the block, the belt and the voltage regulator brushes on back of the alternator. hope it helps.
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staticsan  



Joined: 19 Jan 2009
Posts: 439
Location: Sydney, Australia

PostPosted: Sat Dec 09, 2017 12:45 pm    Post subject: Reply with quote

I've been down the road of alternator not charging. I feel your pain.

The main ground strap from the block to the body is over near the coil.

Standard voltage on original alternator is 13.5V or so. It should drop only under load and if it thinks the battery is charged.

However, 13.5V won't charge batteries with newer chemistry; they want 14.5V. I had four roadside servicemen point this out and two auto-electricians disagree until I bought and installed one of Ideola's alternators and all charging problems went away.

Wade.
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'82 British NA - Which I think I've been very lucky with!
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Porver9two4  



Joined: 23 Jan 2004
Posts: 100
Location: United Kingdom

PostPosted: Tue Dec 12, 2017 10:37 pm    Post subject: Reply with quote

Ahhhh..... interesting.
Maybe I will check my outputs again and double check the earths. If standard voltage is only 13.5V or so, I am probably not far off that and maybe there is nothing wrong with my alternator after all.
What alternator upgrade options are there? Any updated alternators off other brands / models that can be easily swapped on?
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staticsan  



Joined: 19 Jan 2009
Posts: 439
Location: Sydney, Australia

PostPosted: Fri Dec 22, 2017 8:10 pm    Post subject: Reply with quote

I bought this: http://garage.ideola.com/prod-ElectricsUpgrades.html#OEM

Wade.
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'82 British NA - Which I think I've been very lucky with!
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