Can you Parallel two Different Size Generators to Double Power?

two generators connected in parallel to double power

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Going boondocking with a large generator can be difficult because they are heavy. However, if you could parallel two smaller generators together, it would give the same power as one large generator but be only half the weight.

When thinking about paralleling generators, there is one question that many RVers ask: 

Can I parallel two different size generators together?

The short answer is, you can parallel two generators irrespective of their different sizes and brands. All you need is two parallel compatible inverter generators and the right parallel kit. With that, you should be able to increase the power output to meet your RV’s power needs.

In the rest of the article, we’ll take a look at the basics and benefits of paralleling inverter generators, especially two different sizes. We’ll also look at the things to consider before connecting the generators in parallel.

Finally, we’ll take a look at a few parallel kits and how to safely connect two portable generators in parallel.

What does Paralleling Two Generators mean?

Paralleling generators simply means running two generators together. The two smaller units will add up to the same power output as a single large generator. This is done by connecting both generators with a parallel kit.

The goal of this process is to increase your running load capacity without increasing weight. For example, a Honda EU2200i produces 2200-watts of power, and when connected to a similar generator, it will double this power to 4400-watts.

This is a big benefit when you need more load capacity without powering up a larger unit or packing around extra weight and space on your RV trip.

Why do we Need to Parallel Generators?

Primarily, running two inverter generators in parallel will double the load capacity. A 2200-watt generator can run a few RV appliances, but in most cases, cannot power the rooftop air conditioner.

To power your RV air conditioner, you need to connect a 2200-watt generator with your existing unit with a parallel kit and double the output wattage.

But, why run two generators to increase power when you can buy one large unit?

Well, the benefits of running two smaller inverter generators outweigh the benefits of one large unit, especially when boondocking.

Let’s weigh the pros and cons of paralleling generators vs. buying a large unit, so you can decide which is right for you.

Increase and Decrease Power Output

Paralleling generators are beneficial for RVers with varying power needs. If you wanted to run your A/C throughout the day, but your RV demands less power during cooking time or at night while watching TV, paralleling generators are a great option for controlling output.

You run both the units when the power needs are high and turn off one unit when they are low.

Because large generators don’t come with inverters, they won’t be able to vary the output wattage depending on your power demand. It’s either on or off, so if you only need half the power while watching TV, then it would be wasteful to run a large unit.

The Honda EU7000iS is a 7000-watt inverter generator which is an exception of a large generator with an inverter.

Increases Redundancy and Reliability

Running two generators in parallel instead of one large generator increases the redundancy and reliability for critical times.

With two units running in parallel, you will never have to worry about one generator failing and taking the whole RV off-grid. No matter what, as long as at least one unit is running, your appliances and critical systems onboard will work perfectly fine.

This can be a big downside if you have a single unit, as your camping trip may come to a halt if your generator decides not to start.

Reduced Noise Levels

Generally, running two small generators in parallel isn’t necessarily louder than a single larger unit.

The Honda EU2200i at 57 decibels is the quietest generator in its class. And similar sounds from two sources don’t add up to become a bigger noise.

That means, if you run two EU2200i in parallel, the 57 decibels of the two units will not add up and become 114 decibels.

However, because most larger wattage generators don’t come with inverter technology, they don’t have an eco-mode. This means, the engine will not vary speed depending on the load and will run at full throttle, increasing noise.

Plus, the bigger the generator, the bigger its engine and the more noise it will make.

So for most cases, two smaller generators running in parallel will produce less noise compared to a single large unit.

Fuel Efficiency and Runtime

When it comes to fuel consumption, smaller units running in parallel are more efficient compared to a larger single unit.

Though, there are a lot of factors that contribute to how much fuel a portable generator consumes and the size of the engine is one of them.

A generator like the Westinghouse iGen2200 has an 80cc engine and when doubled makes a 160cc engine size. This is smaller compared to a generator like the Westinghouse iGen4500 with a 224cc engine in the same wattage ratings.

Because generators running in parallel divide the load between them, it makes each unit run at a lower load and RPM. On the other hand, the same load on a single unit will make it run at higher RPM, increasing fuel consumption.

In a parallel setup, you can further reduce the fuel consumption by running one unit as the power needs come down. This is not a luxury offered by the bigger units.

Additionally, non-inverter generators don’t have the economy feature. That means, the motor will not vary speed depending on load and will run at full throttle at all times, increasing fuel consumption and noise.

All in all, a parallel setup of two inverter generators is more efficient and can run longer on a single tank of fuel compared to one large non-inverter unit.

Weight of the Generators

The weight of a portable generator is directly proportional to the output wattage of a generator.

That means the higher the output wattage, the higher is its weight.

This can be a serious problem for RVers with large power needs as a single unit capable of powering the RV will be heavy. Loading and unloading such a generator off and on to your truck can be impossible unless, of course, you have it mounted on your RV.

On the other hand, two smaller generators that total the output wattage of a large unit can weigh significantly less. They can be easy to load and unload from the back of your truck or a compartment in your RV.

For example, a 3800 watt unit like the WEN 56380i weighs in at 100 pounds. Whereas a 2000 watt WEN 56203i weighs 40 pounds. For me lifting a 40-pound is easy compared to 100-pounds.

Ease of Maintenance

Having two inverter generators connected in parallel offers better flexibility in terms of maintenance. 

You have the option to keep one unit running to power your RV while you perform some minor maintenance work on the other unit, like changing a spark plug, oil, or cleaning the air filter.

This is one luxury you don’t have if you’re using a large generator for your RV.

However, maintaining two generators requires more labor and time. You have two spark plugs, oil, and oil filters to change. Plus, there are two air filters and carburetors to clean if they get clogged.

On the other hand, a single large unit has one of everything you have to replace and clean, making the work less time-consuming.

Cost

The cost involved in paralleling two generators vs one large unit is a very subjective matter. It depends on the brand and output wattage of the generators you want to buy.

Purchasing two generators of one brand may cost you more than a single unit of a different brand and vice versa.

That means paralleling two Honda EU2200i will cost substantially more compared to a single WEN 56380i in the same wattage rating.

But then you also need to keep in mind that Honda generators are the symbol of quality in the world of generators.

On the other hand, the cost of running two smaller units compared to a large unit is also less. The smaller units have small engines and share the load between them, which reduces fuel consumption.

Does Paralleling cause Damage to Generators?

Most inverter generators these days are designed to run in parallel so that you can use more power whenever needed. So pairing two parallel compatible generators are completely safe and will not cause any damage to the generator or the appliances connected to them.

However, there are situations when paralleling generators can be hazardous to itself and your RV appliances.

The most common are paralleling two non-parallel compatible generators with high harmonic distortion, mismatching the output wattage, or using low-quality parallel cables.

To prevent damage, make sure to use parallel compatible inverter generators. The parallel compatibility will remove the risk of generator damage, and the inverter will keep your appliances safe.

Can you Parallel two Different Size Generators?

Yes, you can connect two generators in parallel irrespective of the sizes, brands, and fuel types. All you have to keep in mind is that they are inverter generators and parallel compatible.

When paralleling two different size generators your power output will be limited by the smaller generator in your parallel setup. This is because generators running in parallel divide the total power draw equally between both the units. This is known as load balancing (more about it below).

But if your RV draws more than what the smaller unit can produce, it will overload and shut down the smaller unit.

For example, let’s say you’re planning to parallel a WEN 56203i, a 2000-watt unit with a WEN 56235i, a 2350-watt unit. The total combined output of the setup will be 4000-watts and not 4350-watts.

Let’s say your RV draws 4100-watts, which means each of your generators needs to supply 2050-watts of power to meet the demand. But, your smaller unit can only produce a max of 2000-watts.

The additional 50-watts load will likely overload the smaller unit and shut it down.

Paralleling two non-parallel or regular generators is something that should be avoided. There are a lot of technicalities that go into connecting these generators which if done wrong can be disastrous.

On the other hand, when paralleling inverter generators of different brands, you need to make sure the parallel ports on both units match. If they don’t match, the only way to connect them is using suicide cables.

Lastly, connecting two inverter generators in parallel is the best option be it of different sizes and brands. This will keep you away from harm’s way and make sure everything works in harmony.

What is Load Sharing of Generators?

Load sharing defines that the load from the appliances is equally distributed amongst both the generators connected in parallel.

Load sharing in a parallel system ensures that no one unit is subjected to greater stress from the load by the appliances. As the load is balanced, the chances of one unit overloading diminish.

There are two types of load sharing in parallel generator sets.

  1. Active Load Sharing
  2. Reactive Load Sharing

With active load sharing, the generator’s engine revs up and down depending on the load. On the other hand, reactive load sharing works by varying the excitation of the alternator.

In both types of load sharing, the inverter generators detect the load on the parallel system and divide it equally among each other to satisfy the demand.

You don’t have to worry about load sharing if you’re paralleling two inverter generators together.

What is Generator Synchronization?

Generator synchronization is a process that helps match various aspects of one generator with the other in a parallel system.

Two generators in a parallel system will be called synchronized if the voltage, frequency, and phase on both the units match. Synchronization is important when paralleling generators as it prevents damage to the system and the appliances connected to it.

However, as an RV owner, you don’t have to worry about synchronizing your generator to use them in parallel if you buy inverter units. Syncing generators is only necessary if you’re planning to parallel non-inverter and non-parallel compatible generators.

Things to Consider before Connecting two Generators in Parallel

There is very little to worry about when paralleling two inverter generators. Be it different sizes and brands, you can run them in parallel to double the power that meets your demands.

However, there are certain things that you should keep in mind to make sure both your generator and appliances connected to it are safe.

Match the Output Wattages

Running two generators with the same output wattage is better than running two with different wattage. This is because the smaller unit will overload quickly. Plus, you’re limited by the output wattage of the smaller generator. 

For example, you have a 3000-watt generator paired with a 1500 watt generator. In this case, the total usable power you have is 3000 watts because the smaller unit can produce a maximum of 1500 watts.

And if the load becomes greater than 3000-watts, the smaller unit will overload, damaging the unit and appliances over time.

Total Harmonic Distortion

As it is using a generator to power your RV with high THD is not advisable. So is connecting two regular generators in parallel with varying THD.

The Total Harmonic Distortion of a generator indicates how much the power output fluctuates when the generator is running.

When two of such units are connected in parallel, and the voltage jumps up and down at various times, it will damage the system as well as the appliances in your RV.

However, inverter generators produce clean power and thus the THD is very low, making it ideal for sensitive electronics.

Safety Considerations

Generators produce electricity, so you need to be extra cautious when operating them.

When running generators in parallel, make sure the cable or parallel kit you’re using is authentic. Avoid DIY parallel cables, just to save a few bucks, as both low-quality and lower gauge cables may melt and catch fire.

There are times when you may not need to run both the units in your parallel system because of low power needs. In such a situation, you can keep both the units connected with the kit irrespective of one unit being turned off.

Leaving both the unit connected while one is running will not damage the unit that is turned off. However, if you decide to remove the parallel kit, make sure to turn off the generators before doing so.

Generator Parallel Kits

A parallel kit is one generator accessory that is a must-have to link two generators safely.

A parallel kit is designed to connect two parallel compatible generators and provide outlets to connect the load to draw the combined power. 

Though parallel kits are not universal and vary from brand to brand. But many generators use the same type of parallel ports and can be used to connect different brand generators.

Here are a few parallel kits from the top brands you can consider.

Parallel Kit BrandSpecificationGenerator Compatibility
WEN Parallel KitRated Output: 30-amp, 3600-watts
Outlets: RV-ready TT-30R 30-amp and L5-30R 30-amp Twist Lock
Honda, Yamaha, Ryobi, Predator, Westinghouse
Firman 1201Rated Output: 50-amp, 6000-watts MAX
Outlets: RV-ready 14-50R 50-amp and L5-30R 30-amp Twist Lock
Honda, Yamaha, Ryobi, Predator, Westinghouse
Champion Generator KitRated Output: 30-amp, 2000 to 3000-watts
Outlets: RV-ready TT-30R 30-amp and L5-30R 30-amp Twist Lock
Rated Output: 50-amp, 5600-watts
Outlets: RV-ready 14-50R 50-amp and L5-30R 30-amp Twist Lock
Compatible with Champion Generators Only
Generac KitRated Output: 30-amp, 4000-watts
Outlets: L5-30R 30-amp Twist Lock
Compatible with Generac Generators Only
Briggs and Stratton KitRated Output: 30-amp, 4800-watts
Outlets: RV-ready TT-30R 30-amp and L5-30R 30-amp Twist Lock
P2200 and P3000
Westinghouse KitRated Output: 30-amp, 3600-watts
Outlets: NEMA 120V TT-30R RV-ready
Honda, Yamaha, Ryobi, Predator, Westinghouse
Honda Parallel KitThis is the parallel cable that can connect a maximum of two 3000-watt units to produce 6000-watt.Honda, Yamaha, Ryobi, Predator, Westinghouse

How to Connect two Generators in Parallel?

You can connect two generators in parallel irrespective of the size and brand. All you need is the right parallel kit for your inverter generators.

With both your generators turned off, insert the parallel connectors into each generator’s parallel ports. Make sure to match the polarity when inserting the connectors.

Note: Connecting the parallel cables with generators running will increase the risk of electrocution.

Next, attach the ground terminals of the parallel cable to the ground ports of each generator. Tighten the ground port screw on each generator to secure them in place.

Start one generator at a time and wait till the output indicator light is on.

Once both the units are up and running, connect your load and turn on the eco-throttle on both the units if needed.

Conclusion

It is without a doubt that two generators can be connected in parallel irrespective of the size and brand. All you have to keep in mind is that they are inverter generators and are parallel compatible.

However, one downside to connecting two different size generators is the power output will be limited by the smaller unit. Once you have everything thought off, it’s just down to getting the right parallel kit and paring them together to double your power.