Does A Portable Generator Charge Its Own Battery?

  • By: Umer.A
  • Date: March 2, 2022
Affiliate Disclaimer

As an affiliate, we earn from qualifying purchases. We get commissions for purchases made through links in this post.

No, a portable generator doesn’t charge its own battery, and it’s not uncommon. Most portable generators require a trickle charger to be plugged into the main power.

Portable generators produce power, and they run different appliances and devices. They lead us to believe that they can charge their battery while running.

The false belief comes from the cars that have batteries in them, and they can charge on their own when they are running. But generators work quite differently, and you need to charge them separately to produce power for you.

In this guide, we will find out how to charge battery of a portable generator.

How Does a Portable Generator Charge Its Battery?

The portable generator doesn’t charge its own battery. Therefore, you will have to plug it in a separate generator for charging, or you can plug it in an outlet. If you don’t do that, the battery will die, and you won’t be able to run your portable generator at all.

One way of charging a generator battery is to use a trickle charger, particularly if you have an automatic start portable generator. Doing this will allow you to keep your battery charged all the time, and it will be ready to start as well. Another benefit is, you won’t overcharge your portable generator’s battery as well.

Trickle chargers are usually available in 6V and 12V configurations. It comes with a charging program that comprises 4 steps: bulk charging, initializing, absorption, and floating.

With this charging program, your battery power will be fully optimized, and it won’t overcharge. It will also allow you to use the automatic start features of your portable generator whenever you need it because, with the trickle charger, your battery will have full power at all times.

You won’t have to do any manual operations with the floating mode to prevent overcharge from happening. When you are not using your portable generator, this trickle charger will keep the battery full in storage.

Some portable generators come with a recoil backup as well. If the battery is dead, you can use the pull start to power the battery up.

In case of emergencies, you can also charge the battery by plugging the charger cord into a receptacle on that generator while it is running. But it’s better that you keep this practice only if you don’t have any other option left.

How Long Does It Take a Generator to Charge Its Own Battery?

The time will mainly depend on the capacity of the battery. If there is a traditional lead-acid battery, it will take several hours before the battery charges sufficiently. Lead-acid batteries take longer to charge because they are not designed to absorb the charge quickly.

But most portable generators of today come with AGM batteries. For example, if you have a quality 30-amp to 40-amp charger, you can charge a 100 amp-hour 120V AGM battery within three to four hours. You can also use solar chargers, but it will depend upon how much sunlight your area receives.

You can use a traditional generator to charge the battery of your portable generator as well. Using another generator to charge your battery will only take around a couple of hours to fully charge.

Can a Generator Charge A 12 Volt Battery?

Generators might have a 12V output, but these generators do not charge your batteries directly when you need much power during crunch times. And there are two primary reasons for that.

First, there are chances that the DC outlet of your generator is limited to an 8-amp current. Therefore, the battery will take some time to charge fully. The second reason is your DC output voltage is regulated on your generator and varies with the RPMs of your generator.

It won’t be an issue if your generator is running on a low load. But it’s not going to work if your generator is running on a medium to high load. The unit will not cut back the charge on a full battery, so charging it for too long will overcharge it.

Therefore, that DC output on your generator is only for temporary charging. If you do it more, you’re risking the battery as well as the unit. So, a better solution here is to go for a proper 120V or 240V charger using the AC output of your generator.

This will do the recharge much quicker, and there won’t be any risk associated with it. This way, the charger is also regulating itself so the amps they are pushing will remain consistent.

How Long Does a Portable Generator Battery Last?

A good quality battery on a portable generator can last up to three or even five years. But it depends on various factors as well. The most important one is how much you are using your generator. If you are using it daily, the battery will only last about a couple of years.

Your charging setup also has a big role to play here. For instance, if the charging process is slow and the battery runs out far quicker, this battery will not last for long.

For the best results, you need to make sure that you properly maintain your battery and your generator unit and check those fluids in a timely fashion. If you cannot do that, your battery will run out of juice and reduce lifespan.

Whether you use your portable generator a lot or not, you still need to fully charge its battery once a month for about 24 to 48 hours. This is an effective way to keep your battery healthy if you don’t use it that much. However, not doing this will make your battery die permanently and prematurely.

How Do I Choose A Generator Battery?

You need to keep in mind various factors when choosing a battery for your portable generator. But, first, you have to make sure that you go for a suitable battery for your application.

For instance, if you are going for a battery you will use in an RV portable generator, it needs to be powerful enough to power all your applications. For home use, you will need a bigger battery.

Also, consider the manufacturer’s specs on your portable generator or its user manual. This is perhaps the best way to find the right type of battery for your portable generator.

Looking at those specs will also allow you to determine your options and costs according to your application. But most people tend to forget this one important aspect here: the availability of a particular battery.

For instance, if you are using an AGM battery in your portable generator, but this is not readily available in your area, you will have to prepare yourself in case of an emergency.

So, keep these important aspects in your mind when buying a battery. It’s not just a matter of using your battery for various applications.

How Do I Charge a Generator Battery?

Electric start units come with a wall charger. You need to connect the battery that you need to charge with your generator. And you need to make sure that the connections are secure. Now plug the charger into a wall outlet and plug the other end into the generator’s charging port.

You will have to charge it for up to 24 hours every three months and ensure that you don’t overcharge it. If you use the generator frequently, you will have to do this more often.

You can connect your battery with a gas generator using the AC port that is present on it. Just connect the battery with your generator and again make sure the connection is secure. And then charge the battery with the unit. The charging pattern and frequency should remain the same.

Can you charge a deep cycle battery with a generator?

Yes, you can charge a deep cycle battery with a generator. The charging process will remain the same, but it will take slightly longer to charge these batteries than AGM batteries.

Can you jump-start a generator battery?

Yes, you can jump-start a generator battery, and the way of doing it is very similar to how you jump-start a dead car battery. Just connect the terminals of the battery and wait for a while. After that, start the generator, and it will jump-start the generator battery.

What kind of battery does a generator use?

Most of the generators that are available on the market feature lead-acid batteries in them. These 12V batteries are just like the ones that are present in your car. There are several different types of these lead-acid batteries like GEL, AGM, and flooded.

Should I disconnect my generator battery when not in use?

If your generator has stopped for a long period and there are no mains to supply to the auxiliary charger, you must disconnect the battery terminal and cut the power. If you have a trickle charger, you can keep your battery connected.


Portable generators are not able to charge their batteries while running. The misconception comes as cars can charge their batteries while running. But this does not apply to portable generators. So, you have to charge their batteries separately. They can power your applications in case of emergencies and or power outages.