acmikee
Well-known member
can you run a ductless split on a generator I've heard both a yes and no. i have a small 7K generator that i use when the power goes out im thinkg about installing a 2 head unit
can you run a ductless unit on a generator
- Thread starter acmikee
- Start date
Depends upon the generator. Probably depends upon the ms too. I had a 7kw Generac that ran my house in outages, which have been many. I ran my 12 and 15 Fujitsu’s with no problem. One of the nice things about mini-splits is that they have an equalizing valve that opens on shut down. With no head pressure to overcome on start-up there is less amperage draw. Make sure your 7kw has a good clean power curve and you should be ok.
pcmeiners
Well-known member
"Make sure your 7kw has a good clean power curve and you should be ok."
Clean power the critical part. During Sandy our neighborhood ran on generators, we lost more than a few electronic devices due to cheap generators.
Clean power the critical part. During Sandy our neighborhood ran on generators, we lost more than a few electronic devices due to cheap generators.
HoosierBuddy
Well-known member
You might consider an inverter style generator if clean power is a concern.
However, I'm curious if anyone has a way to actually check a generator's power quality other than "plug it into a bunch of stuff and see what goes up in smoke". Not an efficient method of checking, but neither is buying a brand new generator if it's not really needed.
I'm using an inexpensive Wen (Yamaha clone) inverter style at home. No issues.
However, I'm curious if anyone has a way to actually check a generator's power quality other than "plug it into a bunch of stuff and see what goes up in smoke". Not an efficient method of checking, but neither is buying a brand new generator if it's not really needed.
I'm using an inexpensive Wen (Yamaha clone) inverter style at home. No issues.
pcmeiners
Well-known member
"plug it into a bunch of stuff and see what goes up in smoke".
Yes that is the popular test method. Of course you could buy or rent a power monitor which costs over $1000 , but not that is not practical. Inverter is the way to go.
Yes that is the popular test method. Of course you could buy or rent a power monitor which costs over $1000 , but not that is not practical. Inverter is the way to go.
dcg9381
Well-known member
Last I checked, not too many inverter gens available in 240v flavor. IF your ductless are 120V, lots of inverter gens under 5kw.
Anyone with a scope can check the quality of power. I'm not sure you'll learn much though unless there is an obvious problem.
We use non-inverter gens all the time in residential. That's what consumer grade generac provides. I have not found something that they wouldn't run in my home... But I also assume larger gens are "more stable" and less sensitive to loads that are within spec.
HoosierBuddy
Well-known member
Before we had an automatic backup generator at work the SOP for a power outage was to fire up a couple of our construction generators 5KW to 8KW, and run extension cords into the office. Blew up several power supplies on computers back in the day.
10 or 15 years ago at least (maybe it's better now) using a standard portable generator to run electronics was an iffy proposition. Again....maybe that all got better. We put in a automatic backup generator (Genrac) and all problems ceased. And it's a heck of a lot handier.
Shoot, back in the old days, sometimes the guys would barely have time to fire up the portable generators and blow up a couple of pieces of office equipment before the power would come back on.
Highbeam
Well-known member
The whole "clean power" thing from inverter generator manufacturers is an overblown marketing scam to sell inverter generators. Yes, the power is usually quite good from an inverter genset but your devices, including a MS, are just not that sensitive. Haven't you seen the third world countries that made these Minisplits popular? Do you think their power is high quality?
That said, there are different grades of non-inverter gensets and some have much more Total Harmonic Distortion than others. It would be better to have a quality genset (inverter or non inverter) with acceptably low THD.
To get 240 volts for the typical MS you need a very expensive and rare inverter genset.
That said, there are different grades of non-inverter gensets and some have much more Total Harmonic Distortion than others. It would be better to have a quality genset (inverter or non inverter) with acceptably low THD.
To get 240 volts for the typical MS you need a very expensive and rare inverter genset.
JerryC
Well-known member
I pulled out an old manual for an EVGA 600W PC power supply I bought in April of 2016.
input voltage spec is 100-240 VAC 50-60hz.
That's pretty tolerant of input voltage.
input voltage spec is 100-240 VAC 50-60hz.
That's pretty tolerant of input voltage.
It’s not the voltage that is the concern, it is keeping the frequency in spec.
As you add and drop loads, the demand on the generator and engine powering it dynamically changes. Inverter gena handle this due to design and how the inverter continuously adjusts to keep the frequency and voltage stable. Non inverter gen sets use a voltage regulator and governor. For small engines when the load changes it may take a bit to “catch up” which means the frequency may droop or spike. Large gens have more rotational mass to ride through the changes better.
As you add and drop loads, the demand on the generator and engine powering it dynamically changes. Inverter gena handle this due to design and how the inverter continuously adjusts to keep the frequency and voltage stable. Non inverter gen sets use a voltage regulator and governor. For small engines when the load changes it may take a bit to “catch up” which means the frequency may droop or spike. Large gens have more rotational mass to ride through the changes better.
JerryC
Well-known member
A 10hz range is pretty broad. Even my Harbor freight 3500w can stay within 58-60hz under high loads. When i first got it I tested it by running a 4 ton and 2.5 ton furnace, 5000btu window ac, 3 pc's, two monitors, and 50 inch tv at the same time.
My 7500 (6500) inverter generator from Northern Tool runs our MrCool 27k two-head unit no problem.
Indexmill
Well-known member
********. Check your math. Jus sayin.
James Condon on you tube works on a lot of generators , he checks the total harmonic distortion and some generators are quite dirty .
how bad that really is for electronics, I don't know
how bad that really is for electronics, I don't know
nadogail
Well-known member
I can't speak about Power Quality, I have not owned an Oscilscope for almost 25 years, but my little generator set has been observed to maintain frequency within 1 Hertz from no load to approximately 8 kw.
It is a 13 Horse Harbor Freight Greyhound Engine, made by Lifan, and a 10 KW (peak) harbor Freight Alternator. The combination of a pretty good Govener and a heavy spinning rotor in the Alternator help maintain a constant speed.
I have not tried to run my AC from the 30 Amp outlet, because my AC is on a 50 Amp circuit.
It is a 13 Horse Harbor Freight Greyhound Engine, made by Lifan, and a 10 KW (peak) harbor Freight Alternator. The combination of a pretty good Govener and a heavy spinning rotor in the Alternator help maintain a constant speed.
I have not tried to run my AC from the 30 Amp outlet, because my AC is on a 50 Amp circuit.
JerryC
Well-known member
Not that hard actually.
The gen has two 13A circuits (or legs).
*the furnaces I tested were replaced a few years ago so i cant go look up the exact specs.
The 4ton pulled about 8A, the 2.5 about 4A
5000BTU window AC (died this year and is gone) pulled about 4A
3 PC's at about 1A each and two Monitors at .5A each so 4A.
50" tv pulling maybe 2.5A.
Furnaces on one leg 12.5A
3PC's, monitors, AC and TV on the other leg for 10.5A
Only thing to be concerned about is inrush current when the blower motors start, The gen can handle some extra current for inrush so I just had to be sure they didn't start at the same time.
Metallitubby
Well-known member
I have one of the ultra-rare 240v inverter generators for home back-up, which happens to be EFI too. It ran my home mini-split just fine during the last 4 day power loss last week.
JerryC
Well-known member
That is a sweet piece of kit.I have one of the ultra-rare 240v inverter generators for home back-up, which happens to be EFI too. It ran my home mini-split just fine during the last 4 day power loss last week.
American Locomotive
Well-known member
Cheap non-inverter generators generally have no problem with frequency or voltage. Their issue is "harmonic distortion" and "noise". Harmonic distortion is basically how close the sinewave is to ideal, and noise is just that - think of like static on the radio. Bad generators have a sinewave that isn't ideal, and have a lot of electrical noise on the output.
The irony is, expensive electronics generally don't care at all about that. The power supplies in modern electronics take all of the incoming AC, convert it to DC, chop it back up into very high frequency AC, convert it back to noisy DC, and then filter it into smooth DC. By "expensive electronics", I mean things like computers, laptops, phones, tablets, etc...
What does care about bad generators are electronics with cheap power supplies. These power supplies are often just some diodes, resistors and maybe a basic transformer if you're lucky. They pass a ton of the input "garbage" right into the output. Unfortunately, a lot of "important" appliances tend to have very cheap and terrible power supplies. Your home furnace, your washer machine, your dishwasher, maybe even your fridge if you have a "smart fridge". Many things like plug-in alarm clocks and audio systems have marginal power supplies as well.
The irony is, expensive electronics generally don't care at all about that. The power supplies in modern electronics take all of the incoming AC, convert it to DC, chop it back up into very high frequency AC, convert it back to noisy DC, and then filter it into smooth DC. By "expensive electronics", I mean things like computers, laptops, phones, tablets, etc...
What does care about bad generators are electronics with cheap power supplies. These power supplies are often just some diodes, resistors and maybe a basic transformer if you're lucky. They pass a ton of the input "garbage" right into the output. Unfortunately, a lot of "important" appliances tend to have very cheap and terrible power supplies. Your home furnace, your washer machine, your dishwasher, maybe even your fridge if you have a "smart fridge". Many things like plug-in alarm clocks and audio systems have marginal power supplies as well.
gsmith22
Well-known member
have you ever run two of these using the parallel kit? I know there were a few problems with the (non-Honda) parallel kit a few years back that have supposedly been rectified. I'm in a location that gets semi-frequent power losses (like 4 times a year) and one of those losses tends to last a few days. House is all electric, don't have natural gas, don't want to install anything propane (long story but I hate propane industry) so two of these could power my whole house and provide piece of mind regarding electronics/THD (i have two very expensive variable speed geothermal heating/cooling units these could power). we lost power just before last christmas for few days, house dropped to 40ish. would love to run one the heat pumps but scared to do that with dirtier powerI have one of the ultra-rare 240v inverter generators for home back-up, which happens to be EFI too. It ran my home mini-split just fine during the last 4 day power loss last week.
Metallitubby
Well-known member
I am the generator model engineer for Honda, so yes I have.
gsmith22
Well-known member
two Eu7000is seem like holy grail from temporary power standpoint requiring 240V, low THD, and gas sipping ability. understanding you work for Honda, is there some downside I am missing with this setup? Guessing cost is the only reason I don't hear more about this since the setup is ~$9500 for gensets and parallel kit?
Metallitubby
Well-known member
Cost is the biggest issue. During this last outage, most of my neighbors had no idea I had/have a generator due to the lack of sound, which is both good and bad. Once people know you have an EU7, people tend to get sticky fingers.
toplessHO
Well-known member
JerryC
Well-known member
"A 10hz range is pretty broad. Even my Harbor freight 3500w can stay within 58-60hz under high loads. When i first got it I tested it by running a 4 ton and 2.5 ton furnace, 5000btu window ac, 3 pc's, two monitors, and 50 inch tv at the same time."
Never said Central Air Conditioning.
mike93lx
ALLIANCE MEMBER
i had a neighbor with one of those. i couldn't hear his generator over mine when i was standing in his driveway, 200' from mine and about 30' from his... very impressive
that was a 13hp 3600rpm unit and even had a honda engine. Sold it and bought a 240v B&S inverter. Still never need it though
Metallitubby
Well-known member
That's one way to deter power outages.
mike93lx
ALLIANCE MEMBER
The best OPE is the stuff that can sit unused.
toplessHO
Well-known member
then why mention the tonnage
JerryC
Well-known member
Because tonnage is something most know about about their HVAC systems vs blower CFM or amperage draw. Also, they are long gone for me to check model numbers and get the exact specs.
jskicet
Well-known member
I recently bought the Westinghouse 15k/12k DF. It has a 713cc v-twin. It's a beast. THD is under <5. It runs the whole house. They run between $2300 to 3K. It even comes with a trickle charger. I have a Honda 3000is but need 240V. Just couldn't justify the cost of the Hondas.
Highbeam
Well-known member
Assuming this is in answer to the original post and topic of this thread, modern minisplit heat pumps are inverters and slowly ramp up their low demand. They don't "hit" a generator with a surge load so this dip in frequency issue is irrelevant. It's pretty great. I remember as a kid the lights would all dim in the house when the old central heat pump kicked on.
Modern gensets actually are quite stable in voltage and frequency. My cheap firman from Costco just gets louder as I load it down. Only loses about 3 hz from no load to full load.