Predator 3500 Parallel Kit: How To Parallel a Generator

Sometimes one generator is just not enough for what you need to run. Instead of buying a more powerful generator and getting more power the simple way, they put one and one together and achieve the same results. Two is always better than one.

The best way to connect two generators and put them in a parallel operation mode is to buy a parallel kit. Which is also the easiest way to get this done. You can use a power cord but it is a little more difficult to get the task done right.

To learn more about this common practice among RVers, just continue to read our article. it explores the issue so newbies and old-timers have the information they need to do this job right. And doing it right is most important as it avoids any damage to your RV and the generators.

What are Parallel Generators?


We know that this topic has been talked about on many different RV websites. Numerous forums deal with this topic but sometimes they take the RV shorthand route and newbies are left confused about this topic.

Then some websites try to explain what parallel generators are but they continue to use the word parallel without defining it so everyone can understand what is being said. To help make things clear, to parallel generators all you are doing is synchronizing them.

If you watch synchronized swimming in the Olympics, you will know that parallel generators work together doing the same thing. Just like synchronized swimmers do in their competitions.

The two generators act as a team connected together to provide more power when you need it. The technical explanation is far more confusing as it involves synchronizing the outputs of two generators that have been connected physically together to act as one unit.

This is done by “matching waveform of one generator output voltage with the other generator’s voltage waveform.” When you do this deed you have to consider the capacity of the generators, redundancy, and compliance of safety, operation and protection issues.

In other words, you should only parallel one generator with another if they are the same make, model, and produce the same power. Then, they should be inverter generators but there are always exceptions to the rule.

Can you Run a Predator Generator in Parallel?

This is possible if they are parallel ready. That is the key to making two generators act as one unit. if they are not parallel ready it would be quite difficult to synchronize them and get the power you need.

This topic brings us to an interesting issue. Finding a parallel kit for the predator generator. A couple of years ago, no one could get one of these from the maker of this generator. Harbor Freight had said that ‘it is coming soon’.

Those kits may be now available from Harbor Freight but we have seen only those kits for their Predator 2000 generator on their products page. we have also heard no word that a kit is now on sale for the 3500 anywhere.

What makes it interesting is that there are parallel kits available for the Northern Tool Power Horse brand of generators. Why we mention this is that the Power Horse is a Predator 3500 in another color.

Harbor Freight does recommend two non-brand parallel kits for use on the 3500 and they are the Firman 1201 & the DuroMax XP3150PK 120-Volt 50-Amp Portable Inverter Generator Parallel Kit.

Why Harbor Freight doesn't make a kit for the 3500 is anyone’s guess especially since they make one for the 2000 generator. If you buy a couple of Predator 3500s then you can still parallel them but have to go outside of Harbor Freight to get the kit.

Can you Parallel Predator 3500 and 2000?


It is possible to do this and if both generators are parallel ready then your work is not going to be as difficult. The key is to have the frequency and voltage points the same. This includes having one of the following items-- compatible alternators or engines, a compatible interface to monitor and control systems, or compatible control systems for load sharing.

The load sharing is important as you have to watch out for under or overload from taking place. It is recommended that you only use the same type of generator when you want to connect two of them together.

That way you will have fewer problems and you will meet the criteria listed above with ease. Then you need to make sure that both units are inverter generators. If you try paralleling one invertor with a non-inverter or two non-inverter generators you will not get the same power output. it will be less than 100%.

The connection is difficult to do and if you make the wrong mistake, you can damage both generators. That has been done before. It is best, and easiest, to simply buy two of the exact same generators to do your paralleling and get the power you want.

#4. Most important- make sure that the voltage and frequency at the connection points are the same. If they are you should not have any troubles. Also, make sure both generators are the invertor type.

We have repeated several cautions because you must get the details right no matter how insignificant they may seem.

How to Parallel a Predator 3500 With a Predator 2000

Since this is a possibility it is important to follow the upcoming steps to ensure a safe connection and operation. here are those steps and make sure to read carefully so you do not make any mistakes. Mistakes will be costly in this situation.

1. Consult the owner’s manual to verify compatibility- compatibility means that they are ready to be paralleled.

2. Buy the right parallel kit- these come with 6 terminals with 4 for power and 2 for ground. Then when you are making the connections keep an eye on the + and - symbols on the parallel port on your generator.

You do not need any reverse polarity here so plug the terminals in carefully.

3. Read the kit’s manual- this is essential as it should tell you exactly how and where to plug in those cables. The manual will help you avoid those costly mistakes and make sure not to leap to conclusions, assume or act hastily.

Generators are expensive and a mistake will have you spending money you do not want nor need to spend.

Predator 3500 Parallel Kit


We checked Harbor Freight's website and there is no mention of a predator 3500 parallel kit for sale. This is kind of strange as the company does sell a parallel kit for the Predator 2000. You will also find those on every store shelf in the country.

Some people may say they saw one for the 3500 but they probably did not read the box carefully enough and did not see the numbers 2000 on it. They probably just saw the brand name Predator and thought it was for the 3500.

We also did a search for a Predator 3500 parallel kit and no one is admitting that they are selling one or have it on their shelves. To use a kit and connect two 3500s together, you have to go outside the brand and find another manufacturer that makes the proper kit for that size of generator.

We will get to that aspect in the next section. There are kits you can use, they just do not come from Harbor Freight for some reason. But keep an eye out as Harbor freight has said many times over the past two years that one is coming soon.

50 Amp Parallel Kit For Predator 3500

While Harbor Freight doesn't make or sell a 50 amp parallel kit for the Predator 3500 generator, there is some good news for those who like to connect two generators and make them one unit.

Other companies have stepped up to fill the void and the two best non-brand kits to use are the Firman 1201 & the DuroMax XP3150PK 120-Volt 50-Amp Portable Inverter Generator Parallel Kit.

These are recommended by Harbor Freight for use on their 3500 generators. That recommendation means that they are safe to use. We have done some extra searching to see if other brands will work.

Cummins, Champion, and Power Horse companies also make parallel kits but there is no word on if you can use those kits for a predator 3500. Cummins did say their kit was recommended for their generators but did not go any further and say you can’t use it on non-Cummins generators.

Other companies that make parallel kits that may or may not be compatible with Predator 3500 units are Pulsar, Briggs & Stratton, Generac, & Westinghouse. There may be others and some off-brands as well.

It would be best to talk to the companies making those non-Harbor Freight kits to see if they are safe to use on the Predator 3500s.

Can I Parallel a Honda and a Predator Generator?


This too is possible as long as both generators are parallel ready. The key is as we have already mentioned having the voltage and the frequency the same at the connection points.

The kits and parallel ready mechanisms all seem to be universal with the 6 point terminals. That makes hooking the kits up very easily for both generators. According to a rumor, Honda is supposed to hook up with anything.

That would include a Predator generator. Then the Honda and the Predator 2000S use the same shielded banana plugs so that makes the connection a lot simpler. Just make sure to read the owner’s manuals of both units and the kit to make sure you connect correctly.

To parallel these two brands, make sure to plug the output terminal of one into the input terminal of the other. This is a common-sense task but even simple things like this can be fouled up.

Just be careful when you do it and check your voltage and frequency at the connection points to make sure there will be no hassles or issues to work on later.

How to Parallel a Predator Generator

Unfortunately, Harbor Freight doesn't make its own parallel kit for the 3500. But such is life and you need to get one of the two kits already mentioned above to do this job right.

Make sure you have the right-sized cables as anything less will cause damage to your generators. Most kits are simple plug-and-play-type systems and all you need to do is put the terminals in the right spot and you are done.

The key is to make this happen is as follows:

- The rms line-line voltage must be the same.

- The phases must be sequenced in the same order.

- The phase angles must be the same.

- The no-load frequency of the incoming generator must be higher than the other generator’s frequency.

Why Not Buy a Larger Generator

There are several reasons why this might not be a good idea:

1. if one generator fails, you still have the other one supplying power. With one generator, you have no power

2. you can remove one generator when it is not needed and save on fuel

3. the larger generator may not fit your RV’s storage system

4. the larger generator may be nosier.

Some final words

When it comes to paralleling generators make sure to carefully read the owner’s manuals that come with the units and the kit. It is expensive to replace generators when mistakes happen.

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