Checking generator output

[Standing Elk]

Ok, need a little advice here. Please see the attached picture. I have my multi meter connected to the generator as seen in the picture, neg. lead to terminal on regulator and pos. lead grounded. My meter is set to 10V DC. At a fast idle the meter is reading right at 6.9 volts. Is my connection correct for this test and if so is 6.9 volts ok? NOTE, that is a voltage regulator on the generator not the original cut out. Thanks

[Chuck Sea/Tac]

Sounds about right. What’s your battery voltage when off?

[ryanheacox]

I see no picture. 6.9V sounds okay though as does your test setup.

[Standing Elk]

Sorry I could not get the picture to load. The battery is brand new and I topped off the charge before installing it.

[Standing Elk]

Battery reads 6.1 when engine is off

[barkleydave]

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NO not correct... you should have a min. of 7.2 volts at high idle to charge the battery. That still is only a average amp charge of 8 amps.

6.1 volts is min. for a 6 volt battery at rest.

[Patrick L.]

I wouldn't worry about it, I think your voltage is fine.

[eagle]

Double the voltage to give you a reference to a 12v system. 6.9V x 2 = 13.8V That'll be just fine, I don't care who you are!

[BRENT in 10-uh-C]

Originally Posted by barkleydave

NO not correct... you should have a min. of 7.2 volts at high idle to charge the battery. That still is only a average amp charge of 8 amps.

6.1 volts is min. for a 6 volt battery at rest.

I disagree with 7.2 volts at high idle, ...remember we are speaking about a generator and not an alternator. A generator's output is directly related to speed of the armature. A generator will not produce peak output until the engine is at cruising speed (-1,800 - 2,000 rpm)

[old31]

I do not see a pic.

[Badpuppy]

7.2V is optimum float voltage for a 6V battery while charging, and 6.3V is nominal for battery at rest. Your regulator output is rather low; they usually are set around 7.4V output due to wire and connection loss to the battery. You can probably run what you have without major problems, but I'd keep an eye on it.

[rotorwrench]

Is this a 2-brush generator with a regulator or just a 3-brush generator? The 3-brush type is limited on how much voltage it will put out. Only the amperage can be adjusted with the 3rd brush. With the Fun Projects regulator it still works the same way with the 3rd brush as a current limiter. The FP voltage regulator doesn't have a lot of voltage to work with even with this type or regulator installed but it has to have the amperage below 15 or it will fry the thing. Amperage output is a lot more important than the voltage.

[Mike V. Florida]

If you do a search for charging voltages of wet cells you will find the range is 2.15 - 2.35 per cell (6.45 and 7.05 for a 3 cell 6 volt battery).


Again if you do another search for the Delco D10SE6I 6 volt regulator, you will find that the one wire regulator has a non adjustable output voltage of 7.7 volts. This the difference when measuring the output of a generator or alternator.