SoftStartHome test on a 7kW Inverter generator

Basics of how to use a portable generator to power your home during a blackout

Dear Readers,

I’ve been continuing my experiments with the new SoftStartHome™ controller. I don’t have a full report yet since it’s too cold and windy here in Maryland for a full current/temperature test.

However, I was able to do a preliminary trial using my Honda EU7000i generator to power an entire house along with a 15-year-old, 2-ton York air conditioner on my twins’ house.

Why is this important?

Since power outages are getting to be more common, it’s important that we consider what it would be like to boondock at home. That’s right… much of what you’ve learned while camping off-grid can be useful if the power goes out at your bricks & sticks house.

Now, I don’t think we’re heading back to Little House on the Prairie days, with a total collapse of the electrical grid. Nor do I think that Mad Max will be taking over anytime soon. But I do believe that everyone should plan what to do if your local electrical grid goes down for a week or two. And being able to power the important electrical items in your house is important.

Do I need an air conditioner in a blackout?

Well, if you’re in any of the Southern states, where the temperature gets to triple digits during the day, you’ll soon find that modern houses weren’t built with enough trees and cross ventilation to be comfortable during the heat of the summer.

And this can be especially dangerous for seniors who may have illnesses that can become life threatening during a heat wave. That’s why there’s so much emphasis placed on getting seniors to cool places during a heat wave.

While you may not be able to cool your entire house to 68 degrees while it’s 110 degrees outside using a portable generator, you should be able to create a cool oasis in the mid- to high-70s for a part of your house. Plus, you’ll want to be able to power your refrigerator and freezer during the power outage, and any medical appliances such as a CPAP machine.

What did I try?

My twin boys have a house with a 2-ton Carrier central air conditioner that’s about 15 years old. It’s time to upgrade it to something with a higher SEER (Seasonal Energy Efficiency Ratio) rating in the spring. So I convinced them I wouldn’t blow up their existing air conditioner during these experiments, which we’ll repeat once the new air conditioner/heat pump is installed.

This was just a proof-of-concept test where we used my Honda EU7000i generator to power the entire house, then cycle the York air conditioner on and off while observing the inrush and static current usage.

No, I don’t have full HRDL (High Rate Data Logger) data yet. No, I don’t have data under a range of ambient temperatures. But yes, I did get a baseline inrush power requirement with SoftStartHome for whatever generator you use. Watch this short proof-on-concept video HERE.

It must be a split-phase 120/240-volt generator with at least 7,000 watts

While you might be able to start and run a central home air conditioner on a smaller (5kW) 120/240-volt generator, we found that most households will be using at least 1,000 watts of static power, not counting the refrigerator that also has inrush current. So my SWAG (Scientific Wild-A** Guess) is that at least a 7kW generator will be required.

And yes, if you plan on running your central air conditioner and possibly your well pump, the generator must be split-phase 120/240 volts. It will have an L14-30R outlet that looks like this.

You can get a 7,000-watt, super-quiet, dual-fuel inverter generator for reasonable money

I really don’t recommend a contractor generator for this application since they use a LOT of gasoline (up to 1 gallon per hour) and their voltage “regulation” can be crude enough to damage home computers, etc.

And while many of you won’t dish out $5,000 for a 7,000 watt Honda like I have, there are even more affordable alternatives that have dual-fuel capability. Take a look at this Duromax XP9000iH inverter generator that runs on gasoline or propane. The ability of propane fueling means you can easily extend emergency power a week o RF more if you add a 100 lb. propane tank.

It has remote electric start as well as sound insulation for quiet running. It’s available at Home Depot for around $2,000 HERE.

With the addition of a proper generator transfer switch or breaker lockout on your residential service panel, this class of generator could power your house for days or weeks the next time there’s a weather related power outage.

Get ready for your next power blackout

I’ve asked for a Duromax XP9000iH generator to experiment with, but it will be at least late spring before I can try it out. My FunkWorks Lab is only 600 square feet, so I don’t have a lot of extra room to set this all up in-situ. But I should have a few other residential air conditioners to experiment on once the weather warms up a bit. Hard to do proper air conditioner testing at freezing temps.

A heat pump can save up to 50% of gasoline or propane usage compared to resistance heating

If you can get your central air heat pump to run from a portable generator, that will save you at least 50% of your gasoline or propane usage. That means you can keep warm for twice as long on the same amount of stored gasoline or propane. But getting a central heat pump to run on a 7,000kW generator can be a problem due to the high compressor inrush current.

SoftStartHome is the key to making this work

I do know that the SoftStartHome will reduce the inrush current on this 2-ton air conditioner by more than 65%. That 24 amps of inrush current is manageable with a 7kW generator rather than a 10kW or 12kW generator. But we shall see…

FYI: One of my Electrical Engineering colleagues on the West Coast has confirmed that his 3-ton air conditioner won’t start on the Honda EU7000i generator, so I’m shipping him a SoftStartHome unit to try. If it works, he’ll gather inrush and static current measurements, which I’ll add to my database.

Knowledge is power, and we’ll soon know more. So stay tuned for more data in the coming months.

Let’s play safe out there…Mike