alternator output in volts

bcny · Jan 5, 2018

My alternator on my tractor puts out 14.8 volts.
Is that too high, and what do I do about it?
Is there an adjustment?
5 years old, 10si type 3-wire internal regulator.
I have resistor instead of idiot light and the voltage sense
wire is connected directly to the output post.
Good grounding as far as I can tell.

stonerock · Jan 5, 2018

sounds like its doing a good job!!

SVcummins · Jan 5, 2018

Don?t worry about it unless the batteries start boiling water out the top then it?s overcharging

Jon Hagen · Jan 5, 2018

It's a but high(14.2 is about ideal) but 14.8 is where most 10SI regulators are set for short trip / quick recharge. Great for a tractor that you run for 1/2 hour per day, not so good for one that runs all day. Most regulator makers offer a 14.2 volt regulator for AG/ industrial/ Marine use for the same price as the 14.8V automotive regulator..

bcny · Jan 5, 2018

Ok, I can take advice, not so bad, it is short run tractor.

David G · Jan 5, 2018

You will be fine, solid state regulator is not adjustable.

Oregon Tractor Jack · Jan 5, 2018

I have a 91 Dodge diesel PU that was running at 14.9 volts. It was boiling the battery. The local auto electric shop suggested I double, double check all of the grounds on the engine, frame, alternator and on the regulator. The voltage sense circuit is pretty sensitive to ground issues. That could be part of the problem. I tried all that with to no avail. I had to eventually have an internal regulator installed in the alternator to bring the voltage down to 14.2. It wasn't expensive to do. I would take the alternator and regulator to an auto electric shop and have it checked out.

OTJ

Bob · Jan 5, 2018

Nothing wrong with that!

Janicholson · Jan 5, 2018

If you put a jumper from #2 spade to the battery Plus post (and remove the little jumper) what is the voltage then? Jim

4play · Jan 5, 2018

I would try to move the sense wire directly to the battery like mentioned above and see if that helps. Also where are measuring the 14.8V at and do you have another voltmeter or DVOM you can use to verify measurement?

rlp in Co. · Jan 5, 2018

13.8 is the ideal voltage for long battery life. Over 14 just wastes power and boils the battery.

MarkB_MI · Jan 6, 2018

Most automotive alternators will start out at around 15 volts, then will drop to around 14 or less once warmed up. If the voltage rises much above 15 volts I'd be concerned, but I think your regulator is fine. At any rate, there's no way to adjust the internal regulator; either it's good or bad.

rustyfarmall · Jan 6, 2018

The voltage gauge in my 2001 Silverado consistently indicates over 14 volts. Been that way since it was new.

Russ from MN · Jan 6, 2018

I was concerned about the high voltage in our Silverado also, called the dealers service department and they said it's normal, don't worry about it. Batteries last over 5 years, so I guess it's OK.

Eric Dahlstrom · Jan 6, 2018

A higher voltage for a short period of time, is actually beneficial for a battery. Especially if it sits for some long periods... As it will help to drive oxidation off of the plates and agitate the electrolyte.

Long periods of over-voltage, when charging, will certain "boil" the battery. Charging should always be monitored, even when you think you're using an intelligent charger.

Alternator output is generally 14.2-volts, and that's nominal, depending on the demand on the system. I would be concerned if was outputting a voltage, much less than 13.6.

alternator output in volts

bcny

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stonerock

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SVcummins

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Jon Hagen

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bcny

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David G

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Oregon Tractor Jack

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Bob

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Janicholson

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4play

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rlp in Co.

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MarkB_MI

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rustyfarmall

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Russ from MN

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Eric Dahlstrom

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