Power factor correction & Bluetti AC500 - am I screwed?

[ForestBaker]

Hello! I'm new at this stuff and would love some advice on whether I'm going to have issues with "power factor correction" when using the 120V/50amp outlets on the Bluetti AC500's.

My plan was to power 2 trailers on our remote property with the following setup (I've already purchased all of this):

• 2 Bluetti AC500 inverters
• 7 Bluetti 300S batteries
• 3K watts of solar power

Each trailer is being built with 120v appliances. And, if everything is turned on at the same time, each trailer will draw about a max of 30amps and 3,000 watts. In addition, we've got outlets people can plug their personal stuff into, so those could add up to 20amps more and whatever watts they require.

I was going to run long cables from the two trailers to the AC500s (housed in a shed) and plug them into the 120V/50A RV outlets.

However, I was just warned that because the AC500 is only pushing out 120V (I guess the normal is 240V for RV outlets), I might have issues with "power factor correction". And this could cause the following:

• Some appliances, like the mini split, not turn on or shut off
• This will cause more heat in the cables/wiring and wear out the appliances faster (sounds kinda scary)

I was told to consider:

• Scrapping the entire Bluetti system (ouch!) and go with inverters that can push 240v to each trailer
• Look into incorporating "ferrite b, passive" hardware that might reduce the power factor issue
• Use 3 separate 120v/20amp outlets on the AC500 to power each trailer, instead of the single120v/50amp outlet. We haven't built the panels on the trailers yet, so this could be an option.

What do you guys think? Is the power factor correction going to be a problem that I need to solve for? If so, what would you do?

Thanks in advance!

Forest

 

[Madco]

I think ypu have gotten some ill informed advice. Power factor can be a problem, but 120V "residential" loads exhibit near unity power factor. Exceptions to this are LED and CFL lighting, and these often present leading or capacitive loads. Another exception is anything with an "across the line" motor. This load will be lagging or inductive.

So in a nutshell, the capactive loads are normally small and don't present an issue. Large inductive loads present other problems like inrush current on starting which will cause inverter trips, but it doesn't sound like you have large inductive loads in your trailers.

Poor power factor will cause more current to flow and thus require larger wire and more power losses in the wiring than a system which has only resistive loads.

240V systems will exhibit roughly the same power factor as the same system running at 120V. Yea the currents will be lower by a factor of 2, but the power factor remains the same. The only real difference is that the real power lost in heating the wiring is smaller by a factor of 2 at 240V.

A long 120V line delivering 50A will be a problem in that large wire will have to be used to lessen the voltage drop.

The early appliance failure argument may have some validity since the currents are twice what they would be at 240V but I suspect it would be hard to make a side by side comparison.

The "ferrite b" statement holds no value if it is referring to adding ferrite beads or torroids to correct power factor. That simply will not work.

So, go ahead and do the 120V circuits to the trailers, but keep the lengths as short as you can. Don't worry about power factor unless your trailers have some big inductive loads, like large air conditioners. If you are going to have large a/c units, look for a unit that is corrected internally. Check the specs, you're looking for power factor and that is usually reported as a number. It will vary between 0 and 1, with 1 being a perfect resistive load. I don't ever recall seeing a residential a/c window unit specification listing power factor though since it isn't an issue in most if not all utlity powered houses.

 

[ForestBaker]

@Madco - thank you so much!

I think the concern was mainly based on running a mini split on top of the other stuff (coffee maker, small microwave, lights, etc.). The person who warned me about the power factor issue said they had run into issues with mini splits for tiny homes and solar setups in the past.

Based on your info, I did more research on mini splits and learned that a lot of units built for the US don't have great power factors because the utilities in the US don't charge customers for drawing inefficient power. In the EU, it sounds like they do, so their mini spit units have much better power factors.

I was planning on using a Pioneer 9K BTU 120v mini split. They have a SEER rating of 22.5, but they don't list the power factor. I've reached out to their technical support and they are going to send that to me.

Assuming the mini split has a decent power factor (like .8 or higher), I think we'll move forward with connecting to the 120v/50amp outlet on the Bluetti AC300.

Lastly, we'll be sure to run larger gauge wire to the trailers because the distance might be around 250ft.

Thanks again for detailed response!

 

[Madco]

You bet, I hope it works out for you. BTW, 250' is really really long for a 50A/120V branch!

 

[Madco]

I had a chance to look at the 250' length. Looks like 1/0 copper will limit the voltage drop to 3% but two runs of that (for each trailer, so a total of 1000') will bankrupt you. And you still need a ground.

A much less expensive way to go is 4/0 URD aluminum triplex. It can be direct buried, so no conduit is necessary-just don't bring it up inside any building!

 

[Madco]

Oops, hit the "done" button a little early.

One problem with direct burial is that frost heave brings up rocks which can nick the insulation. So bury it at the minimum depth per code or the frost depth in your area, whichever is deeper.

 

[DPC]

You might have some lagging of issues with microwave and any motor loads

You can’t do anything without knowing what your dealing with

Nice piece to have around is something like these kill a watt testers

P4400 P3 Kill A Watt Plug In Voltage Tester and Meter

www.aartech.ca

With it you can find out exactly what your appliances draw and what correction you can make
Do a little research on this and you may find some value

If you have old motors that are not cap run, inductive ballast lights old transformer based electronics a watt var meter will help you identify them and you can decide if you want to replace or correct for them

I do not endorse any products or have any financial interest in kill a watt or an my other device like it
Use your own best judgement buy what ever you like

 

[ForestBaker]

I had a chance to look at the 250' length. Looks like 1/0 copper will limit the voltage drop to 3% but two runs of that (for each trailer, so a total of 1000') will bankrupt you. And you still need a ground.

A much less expensive way to go is 4/0 URD aluminum triplex. It can be direct buried, so no conduit is necessary-just don't bring it up inside any building!

Thank you again! I'm totally new to this, so I wasn't aware of the costs/tradeoffs of running such long distances between the solar shed and the trailers. Unfortunately, the best views for the trailers require the longer distance. I'll look into the 4/0URD aluminum triplex and be sure to run it below our frost line. Thanks

 

[Pierre]

You might have some lagging of issues with microwave and any motor loads

You can’t do anything without knowing what your dealing with

Nice piece to have around is something like these kill a watt testers

P4400 P3 Kill A Watt Plug In Voltage Tester and Meter

www.aartech.ca

With it you can find out exactly what your appliances draw and what correction you can make
Do a little research on this and you may find some value

If you have old motors that are not cap run, inductive ballast lights old transformer based electronics a watt var meter will help you identify them and you can decide if you want to replace or correct for them

I do not endorse any products or have any financial interest in kill a watt or an my other device like it
Use your own best judgement buy what ever you like

One of the better and cheaper additions ( about $15 ) to my tool arsenal ! When I sell portable inverter / ups systems I normally advise the client to purchase one as well as they always overload the unit.