How To Test A Generator? – Step By Step Guide

A generator is the most essential machine to vanish the extended blackout but it should be tested before getting a new or used one. In this guide, we will show you how to test a generator completely.

Without further wasting time let’s dive in;

Safety Measures

Safety comes first we need to follow the following steps to make our work hazardous-free.

  • Wear a pair of shoes and non-conductive gloves. Keep stand on nonconductive rubber mate.
  • Check out the voltmeter’s wire if you found removed or cracked rubber Makes sure to cover them with tape. Also don’t ever touch the tips of open wires of the voltmeter.

How to Test a Generator?

For generator testing, we do several tests like output test, runtime test, and load test as well? Below is the step-by-step guide of each test you just need to follow it.

How to Do Outputs Test?

How to Do Outputs Generator Outputs

#1. Start the generator (turn on the ON switch) and turn ON the voltmeter, make sure to set the voltmeter to the Ac voltage, the symbol of AC voltage could be V~, AVC, A~, etc. if you are struggling to find AC voltage make sure to read the user’s manual of your voltmeter.

#2. Ground the voltmeter by attaching a black lead to the frame of the generator with alligator clamping. If your voltmeter doesn’t have a built-in alligator clamp you have to purchase another one.

Checkout our guide about grounding a generator

#3. Now plug the first end of the red wire into the voltmeter and place the other end (tip) into the outlet of the generator. You will see the numbers on the voltmeter which is the actual voltage you are getting from the outlet.

Note: If you are getting less or fluctuated voltage there may be a fault in AVR, below we have listed some tips to troubleshoot the AVR.

How to Troubleshoot an AVR (Automatic Voltage Regulator)?

The major reason for voltage fluctuations, no or low voltage could be AVR failure. You can troubleshoot AVR by following the several steps listed below.

#1. Locate the AVR (automatic voltage regulator), usually present below a circular cover.

AVR (automatic voltage regulator) of the generator

#2. Disconnect the AVR by disconnecting the red and black cables connecting the brushes set and AVR. In my case, I found a red and white lead, however, you may find a red and black lead.

#3. Use tape to cover both ends, so that they can’t touch each other or any sensitive part.

#4. Get a 12-volt battery and two cables with alligator clamps. Connect the first positive clamp to the positive of the brush set from where you have removed the positive cable and the second clamp to the battery. 

#5. Turn on the generator for about 10 – 15 seconds. Now hook the negative line with the negative of the brush set to the negative of the 12-volt battery.

#6. Now grab the voltmeter and check out the two leads with it. If you get 60 Volts you have successfully troubleshot the AVR, if you get less or no voltage your generator needs repairing by an authorized technician.

NOTE: Troubleshooting is the key to restoring the residual magnetism. Please don’t hesitate to do that.

How to Do Load Test?

capacity test of the Champion Power Equipment 4500
Capacity/load Test of Champion Power Equipment 4500

#1. Check out the engine’s oil and fuel level of your unit first.

#2. Turn ON your unit and start connecting load gradually; if you have a modern generator there may be an LCD that indicates how much load you have added and how much can be added on the top.

#3. If you have a machine with 5000 running and 6000 starting watts, it should provide at least 4700 running and 5500 starting watts. Though it is prohibitive to put 95 – 98% load on the generator still you have to do it at least one time to check out the full capacity of the unit.

NOTE: There may be a difference in the load test with gasoline, propane, diesel, or solar, so please try to read the whole specification of the unit and match the load test as per the statements of the manufacturers.

How to Do Run Time Test?

#1. Fill up the tank with gasoline or diesel or attach a tank of propane if your unit is working on dual fuel.

#2. Run your unit on Eco mode, 25% load, 50% load, or 75% load, make sure to set a stopwatch once the generator stops you will get the actual runtime of your unit on a stopwatch. On eco mode, you will get the highest run time however on 75% load you will get the lowest runtime.

You can check out our guide about how much the generator lasts in terms of life and runtime.


No matter whether you are going to get a used or new generator, please do at least a load and output test to avoid long-term investments. These tests will not only save you money but also saves your sensitive equipment from fluctuating or low voltages.

If this guide helps you please share it with your beloved ones for supporting us, we are open to solving your quarries please let us know in the comment section

Frequently Asked Questions – FAQs

How do you diagnose a bad generator?

I do the following things to inspect whether the generator is in good condition or not.

-Look for visible crakes and damages.
-I inspect outputs; if there is perfect voltage with no voltage fluctuation its outputs are ok.
-If there is a startup delay make sure to check out the battery’s condition and other kinds of stuff.
-Run the generator and inspect the noise, fumes, etc. to observe the engine’s condition. If you found strange smells and sounds, there may be a fault in the engine.
-I do load and run tests as well for double check.

How do I know if my voltage regulator is bad on my generator?

Low, high, or fluctuating voltage is the major sign of bad voltage regularly, you will find the unstable voltage that may cause several appliances failure, also your batteries terminal may corrode rapidly.

Can a generator be repaired?

Yes, it can be, but some repairs may cost you more so if your unit needs small repairs you can go for it, otherwise purchasing another unit is a wise decision than a huge repair.

josh Milan


Josh is a highly skilled electrician with specialized expertise in the field of generators. With years of experience under his belt, he has established himself as an expert in all aspects of generators, ranging from installation and maintenance to troubleshooting and repairs. Josh’s in-depth knowledge of electrical systems and his commitment to staying updated with the latest industry advancements make him a reliable and sought-after professional.

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