Learn About Connecting Generators In A Parallel Configuration

Anytime that you need additional power, you might want to consider connecting two different generators in a parallel configuration.

On the other hand, this isn't exactly a simple process. Many different delicate steps are involved along the way. Keep reading to learn about what parallel generator configurations are, why you might need one, and how you can accomplish this successfully, among a lot of other useful information.

Parallel Generators? What Is That?

Parallel generators just means running two generators in parallel. In short, you connect two different generators in a parallel configuration so that you can get twice as much power output. Generally speaking, this is much easier to do if the two generators are identical in their power output or if they're both the same brand.

If you have a parallel-capable generator, then it's a lot easier to create a parallel connection. Having said that, if you have a portable inverter generator that isn't actually parallel capable, then the process involved is a bit different. Such connections are still possible, but you might need wires that can handle dual-output power and a suitable parallel kit.

Is It Possible To Parallel A Pair Of Non-Inverter Generators?

Technically speaking, you can use a voltmeter and tiebreaker to parallel a pair of non-inverter generators. You will need to both phase match and sync the two non-inverter generators. However, your output isn't going to ever reach 100 percent. Also, the procedure is rather complicated. Any errors along the way can risk serious damage to both of the generators.

The main issue here is that both of the non-inverter generators might have waveforms that aren't in sync when the generators are in parallel. This means that the connected generator is susceptible to an overload. Given this, it's strongly recommended that you not connect a pair of non-inverter generators in a parallel configuration. For the same reasons, you should avoid putting any combination of an inverter and non-inverter generator into a parallel configuration either.

Using a pair of inverter generators works out much better. They can communicate with each via frequency and sync up better. Based on load demand, two inverter generators in a parallel configuration can even lower or ramp up the power output as needed or appropriate.

Can I Parallel Generators Of Different Sizes Or Brands?

It is possible to put two generators of different brands or sizes into a parallel process and configuration. If both of those generators are also parallel-capable, then it's even easier. Just remember that one thing both generators need to have in common is being the inverter kind.

If both of them are parallel capable, then you can use a parallel kit to make connecting them easier. Most parallel kits have six terminals. Four of them are power connectors, and the other two are just ground cables that you connect to the generator ground point.

If one generator is parallel-capable, and the other isn't, the procedure is different. This procedure is also something you can use when neither of your generators is parallel-capable.

Start with the output port of your non-parallel generator, and connect it to the input on the other generator. Then, connect the appliance that needs power to the second generator, the one with parallel-capability. Next, start up the non-parallel generator before starting the second generator. This sequence of steps lets you connected two differently branded or sized generators in a successful configuration.

How Do I Connect Parallel-Capable Generators?

First off, make sure that both of the generators that you have are actually parallel-capable. If you notice that both of them are the same model, then things should go a lot easier for you.

Either choose a parallel cable or a parallel kit. If you're not sure which to use, go for the parallel kit. It's much simpler to use and has a much lower learning curve.

The parallel kit here is the same as already mentioned, so you have four power connectors and two ground connectors. Make sure that you connect the ground ports. Also, check your generator's parallel port for a plus/minus sign. If one is present, then you need to read the parallel kit manual in order to be sure you connect things properly.

You may know that there aren't a lot of generators on the current market with parallel capability included. In fact, one certain generators in the small- and mid-size ranges come with this.

Fortunately, you won't have to control, manage, or monitor the power of either of these generators. When both of your generators are parallel-capable, then they automatically raise or lower the power produced based on the demand placed on them. This makes life much easier when you're running such a setup.

Will I Hurt My Generators If I Run Them In Parallel?

Generators which manufacturers design for parallel-capacity aren't going to suffer damage, provided you only use properly-sized cables. You should also make sure to follow any instructions that the generator manufacturers provide so you can better prevent generator damage. Again, it's not necessary for both generators to be the same brand, make, or model, but if they are, it might mean less documentation to read through. Another good reason to do all this is not just to avoid generator damage, but also to avoid potential damage to whatever appliances are hooked up to your parallel configuration of generators.

Why Does Anyone Even Run Their Generators In A Parallel Setup?

Everyone in the modern world is dependent upon electricity. Even certain elements of the Amish population don't live without it, even if it's just at work. If you're already using a generator at times, you're going to discover that one generator simply isn't enough to meet your power needs. Extra power might be necessary to run appliances, such as a microwave, fridge, and air conditioner. When this happens, a parallel generator configuration is likely to be your only option to boost your available power output overall.

Why Can't I Just Buy A Bigger Generator?

There are quite a few good reasons for not doing this. For starters, if you already have a small or medium generator and still need even more power, then getting a larger generator isn't going to work out. Rather, you can get another one identical to what you have so you can connect them and get more power.

You should avoid getting one large generator because only portable generators have a high capacity for power production. They're also not nearly as quiet or fuel-efficient as inverter generators. In nearly every objective aspect, inverter generators prove superior to traditional and/or conventional generators.

Another thing to keep in mind is that if you only have one large generator, and it fails, then you can't run anything at all that needs electricity. Alternatively, when you have a pair of parallel generators, if one of them fails, you can still run basic appliances and operations off of the other one. This is very beneficial in certain circumstances.

One final advantage of two smaller generators in parallel configuration is that you can't move a large generator everywhere you might want it. Sometimes, one small inverter generator is plenty for going camping, tailgating, and other outdoor activities. If you don't need both, you can leave one behind.

Parallel Generator Load Sharing

When two generators are running in parallel, then the electrical device load is distributed equally in between them. This is what's called generator load sharing. Those who like to get technical also might call it the 'proportional division of KVAR and kW'. KVAR stands for Kilo Volt Ampere Reactive.

In order to avoid putting too much stress on either generator, the cumulative load should be shared equally between both of them. An advanced system often monitors this. As load demand goes up, both generators will start burning just as much fuel as the other in order to avoid overloads and system instability.

Equal load sharing is something that you can accomplish in several different ways. One that you should know about is the Isochronous kW and KVAR method of load sharing. This particular method uses the speed governor of each generator to ascertain the proportional share of the active power that the system requires.

I Have An Air Conditioner In My Camper. How Many Watts Does It Need?

Air conditioners for camper vans use varying levels of watts for power. One primary difference separating all of them is their BTU ratings.

BTU is a unit of measurement in Britain for thermal energy. However, air conditioning units usually have two different watt ratings. The first is how many watts are needed for startup, and the second is how many watts are necessary for the steady operation of the unit.

In most cases, the startup watts will outnumber the running watts, as an air conditioner needs more juice to get going than it does to keep running once operational. That means that whatever generator or generator configuration you set up needs to output more watts that your RV AC needs.

The following are different air conditioner BTU levels and the corresponding watts necessary for startup and operation:

  • Air Conditioner: 15,000 BTU
  • Startup Watts 3200-3500
  • Running 1200-1700
  • Air Conditioner: 13,500 BTU
  • Startup Watts 2700-2900
  • Running 1000-1300
  • Air Conditioner: 10,000 BTU
  • Startup Watts 1900-2500
  • Running 600-650
  • Air Conditioner: 7,000 BTU
  • Startup Watts 1600-1800
  • Running 500-650
  • Air Conditioner: 5,000 BTU
  • Startup Watts 1100-1300
  • Running 300-450

Generator Synchronization

Anytime you connect a pair of generators in a parallel configuration, they need to be synchronized in order to avoid damaging both of them. In a state of synchronization, the voltage, phase, and frequency of each generator have to match up. If you parallel more than two generators, particularly when some of them aren't actually parallel-capable, then you have certain conditions that need to be met.

Phase Angle Difference: If you're employing a three-phase system, then the phase angle difference between two sine waves needs to be zero.

Phase Sequence: In a three-phase power output, you have to ensure that every generator has a correctly ordered phase sequence, which means that the voltage peak on sine waveform matches up.

Voltage Amplitude Difference: There has to be a match between the sine wave voltage peaks, as this indicates that every generator is producing the very same voltage level.

Waveform: The waveforms of every generator in the configuration need to be sine waves.

Aspects To Be Mindful Of When Doing Parallel Generators

Most of the time, users connect a pair of generators that are the same level of power output and even manufacturing brand. This is a smart move, given how it prevents a lot of compatibility issues. However, this doesn't actually mean you can't connect two generators from different brands or even of different sizes.

If you're not sure if you can do this or not, check both your generators for the frequency and voltage at the point of connection. If they match, you can probably hook them up into a larger parallel configuration. Regardless of what two generators you hook up with one another, you need to verify several things across the board. These include the engine compatibility, alternator compatibility, interface compatibility, and load sharing.

1) Alternator Compatibility: The alternators of two connected generators will be compatible, provided that the currents in between them don't actually flow into one another's circuits. Each alternator has protecting relays in-built to prevent situations like these, but there are times it can still impact the operation of the generators. The lower-frequency generator acts as a load for the other unit when this happens. This particular situation is called 'motoring'. If it happens, it can wind up overloading every generator in the configuration. Entire system failure is an eventual possibility.

2) Engine Compatibility: Engine capacity for generators gets measured in kW, which is short for kilowatts. Anytime you can, run two generators that have identical kW. This lets you operate them in tandem for higher loads, and it's also useful for preventing system overloads. Consider the possibility of having one generator rated for 200kW and the other for 400kW. In such a case, you're only going to get your load up to 200kW. Your load-supplying capacity will be maxed out based on the output ceiling of your smaller generator.

3) Interface Compatibility: When parallel configurations were first used, every generator had to be manned all the time because every single process required manual operation. That's no longer the case, since modern generators can communicate with one another automatically. Parallel-configured generators need a clear communication channel in order to automate continuous operation.

4) Load-Sharing System Compatibility: Every generator in the configuration must have matching frequency and voltage. Once the configuration is established, then monitoring the current or voltage is no longer possible. Any imbalance in the power output can create a reactive load imbalance between the configured generators.

Why Are Inverter Generators The Best Options For Doing Parallel Generators?

Inverter generators are typically the best way to go if you want to run a parallel configuration. First of all, since they can run parallel, they can give you more power. Secondly, they are incredibly fuel-efficient, giving you more power for the fuel you put into them. Third, they are lightweight and very portable, making them much more suited for moving around and mobile applications.

These kinds of generators also typically run very quietly without disturbing you a lot with noise. Also, many inverter generators come with an eco mode that allows for variations in throttle power.

Is Isochronous The Only Way To Parallel Generators?

It's one way, but there is another. It's known as 'droop', and some find it easier to use. Droop is actually often simpler when generators don't match in size or brand. However, the downside of droop is how much wider variety there is in frequency and voltage levels. Isochronous is still the better way to go since control systems in the generators are used for proper and safe load sharing.

How Can I Improve Compatibility If I Want To Parallel Two Non-Inverter Generators?​​​​

It's a bit more work, but there are several things you can do to improve the compatibility of two or more non-inverter generators that you would like to put into a parallel configuration. Here are four of them:

1) Alternator Compatibility: A frequency mismatch between generators can trigger the earlier-mentioned motoring. This has the potential to overload each generator and even the distribution system when everything is hooked up. Fortunately, most manufacturers list their alternator compatibilities in their instruction materials or on their websites.

2) Engine Compatibility: If you have multiple generators with roughly equivalent engine capacity, or even the capability of adjusting their capacities to an equivalent kW value, then you can improve your system efficiency to a tremendous degree.

3) Finding A Good Adapter Cable: You might have to use adapter cables if you want to appropriately parallel non-inverter generators or units from separate manufacturers. Every manufacturer has at least one companion kit associated with it. Follow the steps listed in the instructions of whatever adapter kit you buy or assemble. That way, you can parallel your generators safely, efficiently, and with balanced load distribution.

4) Verify The Load Sharing: Every generator in your parallel configuration should get adjusted to match each other. If it's possible for you to do so, monitor the bus voltage or speed in each generator to better balance the cumulative production. That helps ensure one generator isn't doing more work than the rest.

Can I Parallel With Solar Panels?

There are quite a few solar-power generating devices, not just panels, that produce electricity and/or power you can use. If you have such technology at your disposal, it can save you money while giving you more juice. If you live, work, or spend time in hot and dry regions, then you might save quite a bit of money on fuel in doing this.

Remember, you can hook up any generators you want, even when they're different brands or sizes, just as long as they have the same frequencies and voltage at the point of connection.

What Are The Advantages Of Running Generators In A Parallel Configuration?

As mentioned earlier, you get more reliability. You can have one generator go down and still be drawing power from the other one.

Closely related is service and maintenance. A parallel configuration lets you take one generator offline so you can tend to its needs while the second generator still hums along.

Will I Hurt My Generators With A Parallel Configuration?

It's honestly quite possible in certain situations. For starters, you should know that some generators are actually designed to be paralleled. So long as manufacturer instructions are followed precisely and the right cables get used, no harm should fall these generators. It's what they're honestly meant for.

Final Thoughts

Most users who parallel their generators do so because they need more power than one generator can run. Alternatively, they might need the power of a big generator, but they can't physically move it around where they need it.

A common application for portable gas generators is starting up the air conditioners fitted in modern RVs. They commonly are rated for 15,000 BTU and need more watts to start up and get going than one smaller or medium generator can do. A parallel configuration lets users get the AC going when they're vacationing or traveling in their RV. Since a lot of RV travel happens during the summer, air conditioning is a creature comfort. Honestly, it's even a necessity in many parts of the country.

Summer isn't even the only time RVs need AC. Many 'snowbirds' migrate from mild climates during the winter, such as residents of the California mountains heading to Arizona, or retirees in the Carolinas and midAtlantic states headed to Florida for the winter.

Small and mid-sized generators are much easier to move and carry than one big one, and it means they can start and run their AC with a parallel configuration. Of course, other uses include refrigerators and cooking, and travel isn't the only application. Worksites, tailgating, camping, natural disasters, and power outages all make this technology quite useful for a society that requires constant power to be available.

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