charger missing ac generac

Charger Missing AC Generac: Causes & Solutions

One of the most common issues with a Generac generator is their Charger Missing AC error message. The message appears on the control panel of the Generac generator.

So what to do when charger missing ac generac error code appears?

If the Charger missing ac message appears after a power outage then it’s a false alert. However, it’s a problem if there’s a power loss in the charger during the time generator takes to start. It’s because either the T1 connection is lost or the fuse is blown. A faulty charger can also be the cause.

If you need the solution to these problems then you’ve come to the right place. We’ve broken down the causes and the solutions in detail. 

So join us in the full discussion! 

What Does The Charger Missing AC Mean?

The “Charger Missing AC” is the 2780 error code of the Generac generators. This error code appears on the control panel of the generator. 

The message means that your Generac generator’s battery is not being charged by the built-in charger. Apart from the error message, you can detect this problem through the indicators as well.

There is a yellow or red light indicator on the side of the Generac generator. The yellow light shows that the charger is missing. It could blink yellow or green-yellow at the same time.

Everything else may be operational. But the indicator will remain illuminated because the microprocessor in the generator is still registering that particular issue.

Similar to Generac generators, Westinghouse generator faces light issues when there’s an issue with the battery or the fuse. So, prioritizing the indicators is necessary.

Even if the error message doesn’t appear you should understand the issue by the indicator. Because it’s necessary to address the problem. The battery charger of the generator is responsible to charge the battery.

If the battery is not getting charged, then your generator will not run or even start properly. The built-in battery charger requires 120 volts to operate under ideal conditions. 

The problem occurs due to various reasons. In our next segment, we will identify the causes for it and also provide you with solutions.

Causes & Solution For Charger Missing AC Genrac 

The Generic generator has a transfer switch which may come under other names. Such as T1 and T2. T1 and T2 are the ATS’s load terminals. They are connected with the N1 and N2 terminals respectively.

generac not activated charger missing ac
Source: Reddit

N1 & N2 terminals transport energy from the generator to the load. Especially, In a 240/120V single-phase system. The electrical load changes from a normal power source to a standby power source. 

When a power supply fails or there is a significant loss in power, the transfer of energy occurs automatically. However, a disconnected circuit breaker fuses with the transfer switch and prevents power transfer.

As the circuit breaker or the switch stops operating, the problem Charger Missing AC error appears. This is how the transfer mechanism works in Generac generators.

This problem gets initiated through some causes. Here we short-listed the causes and solutions for them. 

Reason SymptomSolution 
False Alarm From Power Outage“Charger Missing AC” appears every time after a power outageKeep a backup power source
Connection Problem in T1 TerminalPower loss in the chargerReplace damaged wires and T1 fuse if it gets blown
Failed ChargerGives false readingReplace the charger

For more details proceed to the next sections.

Cause-1: False Alarm From Power Outage

It’s pretty common in Generac generators to show a “Charger Missing AC” error code when there’s a power failure. The error code persists till the generator starts and proceeds with transferring power.


This problem can be treated as a false alarm. As you know there’s no serious malfunction that’s causing it. But you can keep a backup power source for the generator. 

For example, a battery pack or a portable solar panel. That way, the generator will be able to transfer energy from the power source.

Cause-2: Connection Problem In T1

Earlier we mentioned the T1 terminal which is located at the transfer switch’s side. It works as a circuit breaker and protects the system from power outages. 

When the power from T1 is not sending 120Vs to the generator, the “charger missing AC” alert activates. Here a power loss happens in the charger which activates the error message.

A blown T1 fuse in the transfer switch could also be to blame. Problems in the terminal can also cause the generac generator to run while power is on.


The power loss in the charger can’t be taken as a false alert. Instead, it could be a wiring issue that occurred during installation. Look out for loose or damaged wires. 

As for the blown T1 fuse, you can replace it with a new one. T1 breaks when there’s the presence of aberrant power in the input. Under such circumstances, it causes a disconnection between the battery and the load. 

As a result, the generator will stop when it faces a lack of voltage. Such activity is harmful to the battery. Rather than purchasing a new battery, changing a fuse is a lot easier and cheaper.

You can watch the following video for a better understanding-

Cause-3: Failed Charger

If the charger itself is faulty then such error code might appear in the generator control panel. Test the battery charger to be sure.


You can test the battery charger with a multimeter to see if the reading is incorrect. Depending on the type of battery, the readings will be between 12-14V. 

If the readings are incorrect then get a new charger from the Generac depending on your generator battery model. You can check out the following products-


  • You can use a separate inverter to charge the generator when the battery isn’t receiving power from the charger.
  • Install surge protectors to prevent the tripping of circuit breakers during power outages.
  • Keep a backup power source.
  • Use a generator cover to prevent loose or damaged wires.
  • Hire a professional for repairing critical issues like connection problems in T1.
  • Conduct weekly tests on the Generac generator.


That’s all for today regarding charger missing ac generac. Hopefully, you were able to detect the root cause of this problem in your generator.

You may use alternative charging methods if such a problem arises. But it’s better to resolve the issue as soon as possible as it can threaten the generator’s battery life.

Good luck!

Frequently Asked Questions(FAQs):

Can Generac generators charge their own battery?

Yes, it can charge its own battery with the built-in battery charger. When a power outage happens this built-in battery charger charges the battery to keep it operational. The charger is powered by the engine.

What is error code 1100 on Generac?

Generac error code 1100 refers to an over-crank error, which arises when the generator makes two unsuccessful automatic start attempts. This error can occur due to various factors, including a malfunctioning ignition coil, a fuel filter that has become dirty, or a fuel line that is obstructed. 

What does the charger warning indicate in the Generac generator?

The maintenance notice on a Generac generator is displayed when the controller detects a battery voltage below 12.5V following an 18-hour charging period. Several potential causes can trigger this warning, such as a malfunctioning battery, loose connections, or a defective ignition coil.

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