Help me pick a generator size

[dlundblad]

Originally Posted by skyactiv
Be careful what you run on a typical non invertor portable generator.. Electronics in a modern furnace are not something I'd hook up to an old fashioned generator. Lots of people in Clintonville, OH lost their power for a week, bought or had a cheap generator to run the fridge which the fridge broke down due to dirty power.there an article on it somewhere.


Non inverter generator. I guess I didn't know this was something I should look out for?

Would a roll cage model from HF not be one?

 

[tundraotto]

No - it would definitely not be one.

Inverter generators are much more expensive.

 

[1978elcamino]

Northern Tool has their house brand "powerhouse" that just came out with a 7500 inverter genset. Its quite pricey at 3 grand but about half the price of a similar Honda. I would put money on seeing the same genset in red with the name Predator on it soon at the Harbor.

 

[eljefino]

Might be better picking your transfer switch first. Like this one for your six essential circuits and note its wattmeter. Wire it up, especially to the well pump, and see what the surge watts are. Well pumps are all over the place-- I have a shallow well jet pump that runs on 120V and has a "6.8 amp" rating on its plate, yet will draw ~2500 watts briefly on startup.

Hey, that reminds me, I have a chinese 2500 running/ 3250 watt generator that works perfectly for my house and its power outages. I just make sure to have it good and warmed up before I hit the switch for the well pump. A 3600 RPM non-inverter generator will chug through motor start up loads that inverter models will stall/ abort on thanks to the rotational inertia.

Note, I put an aftermarket propane carb on it but would get a dual-fuel model if I had to do it over again.

 

[whatnext]

I have a 6 circuit transfer setup like mentioned above. They are not cheap ~$300 but allow safe hookup of circuits to the generator by isolating each circuit from the rest of the house when flipping the switches to generator mode. Also note the heavy connector cable for the generator. No extension cords here.

 

[JTK]

Originally Posted by PWMDMD
Originally Posted by JTK
The problem to me when you go into the ~7KW+ range with a portable gasoline powered unit is you are going to burn in excess of a gallon per hour if the generator has a load on it.

Will you have that amount of fuel on hand? Will you be able to source it during an outage?

I get it that you need it if you have to run well pumps, a/c, etc, but to me, for a roll-around portable unit, it's all about being able to minimize during an outage. I'd rather have 2-3 small units, with some or all being inverter units.


I've got a 7500watt continuous/9500watt startup and when power outage is a possibility I have 6 gallons in it's tank, two additional 5 gallon cans and in the event of a long outage a 38 gallon tank in the Tundra and another 16 gallons in the RX350 for a grand total of 68 gallons of fuel. . My point...as long as you can syphon gas from vehicles they can be a great backup for the generator. That will give me close to 30 hours at full output and double that more normal outputs.

Now my in-laws propane powered Generac will do a solid week on a tank of propane but it's was also 20x the cost.....



I get that if you've got multiple vehicles and you can save some fuel in one of them.

I just read the specs on the Powerhouse PH3300i I've had sitting in my garage for two years. It came "free" with the travel trailer my inlaws bought two years ago (and haven't used that either. LOL) It will supposedly run 7.3hrs full load and 16.6hrs at 1/4 load on it's 4.34gal tank. I believe it's a 270cc Lifan engine in it. I test ran it for an hour or so and changed the oil on it. It's been sitting with a $5 HFT battery tender on it since it has E-start, remote start, etc.. They're a pain to work on with all the insulated panels encapsulating everything. Not a bad running small gen though.

 

[Astro_Guy]

Originally Posted by dlundblad
Non inverter generator. I guess I didn't know this was something I should look out for?
It really depends upon what you need or want to power. Inverter generators produce a cleaner wave form that is more friendly to modern high tech electronics. In my experience, front loading washer and drier by LG would not run on the power from a Champion 4000/3500 starting/running watt conventional generator. Cyberpower and APC Uninterruptible Power Supplies (UPS) for my computers didn't like that dirty power either. Then I bought a Predator 3500 inverter generator and the UPS systems are happy. Haven't tried the washer and drier, but I am willing to be that they would work just fine.

Your well pump will run just fine with a basic 3600 RPM generator. It's the newer high efficiency stuff you have to worry about, including the latest refrigerators and the blower motor on your furnace.

 

[spasm3]

OP, what type furnace? Gas?

 

[cronk]

I have a Champion 3500w running 4000w surge. It will run my well pump if NOTHING else is on. It runs 2 fridges, my furnace and some lights no problem. It is really undersized for my backup needs, but gets the job done if I carefully balance the load.
I think the op is choosing wisely to look in the 7000w class. That would run his needs comfortably. 5000w/5500w would be the bare minimum.

I havent found the need for an expensive inverter unit for occasional home backup use. My non inverter Champion has ran my household items just fine.
Champion does offer some inverter units with an open frame they call "Digital hybrid inverter" that are a bit louder than the enclosed rv style quiet inverters, but at a lower cost, that might be a good compromise, clean power, fuel savings and a happy medium in price.

champion 5000w running inverter

champion 7000w running inverter

 

[Donald]

Get a clamp on AC-ammeter with peak hold. Not very expensive. Start measuring all your loads.

Well pump. I assume submersible? Two wire or three wire? Two wire has starting capacitors in the pump, 3 wire has them in the pump control box in basement. 3 wire draws less.

I would go with propane or natural gas if possible. Propane never goes bad. Never gums up the carb. No choke needed. Gasoline is a PIA if you want to always have few days on hand of fresh gas.

You will need a transfer switch. Big chain. CO detector. Some kind of tent if it needs to run in bad weather. Needs to be 20' from the house so no CO will come back into the house. People die every year from a generator producing CO and no CO detector.

 

[dlundblad]

Originally Posted by spasm3
OP, what type furnace? Gas?


Yes. Propane.

Unrelated, but I do have a 1000 gallon tank with hopes to eventually get one of those Kohler outdoor models.

Can't find it at the moment, but they make a 7kw model. I won't need to run the whole house.

 

[Lubener]

Originally Posted by dlundblad
Happy Friday BITOG.

For power outages, I'd like to run the water pump, a few lights, the furnace (if needed), a fridge and freezer. The idea of being able to run everything at once sounds nice, but it isn't necessary either. My concern is excessive fuel consumption by getting a larger model that can run everything. I'm thinking something around 7kw. Unsure of fuel type, but will likely just get a model from HF for now.

What's everyone's thoughts?


You have to add up everything you plan on running at one given time and add some cushion on top of it. Without those figures, everyone is just guessing.

 

[hatt]

I'd get the smallest gen that will run the well. Big generators burn a ton of fuel. Fuel that hardly anyone stocks. If you want to run everything in the house I'd get a whole house with a big propane tank.

 

[spasm3]

Originally Posted by dlundblad
Originally Posted by spasm3
OP, what type furnace? Gas?


Yes. Propane.



I have a gas furnace, gas water heater. And a 1/2 hp well pump. I power with an HF 4375 as it was the smallest 220v unit. With everything else off it runs the fridge, well pump, and furnace, a few lights, tv.

I I need to run other things , I keep the well pump off and alternate the furnace and well pump.

It will run about 15 hours on 4 gallons.

I also have an over powered older genset that's an 8k/10k unit (18hp). It will run everything in the house except the clothes dryer with everything else on.

Problem is it burns over a gallon a hour!

3 5gallon cans is a 3 day supply for the 4375 unit, but not even a day for the big generator.

 

[tundraotto]

Originally Posted by hatt
I'd get the smallest gen that will run the well. Big generators burn a ton of fuel. Fuel that hardly anyone stocks. If you want to run everything in the house I'd get a whole house with a big propane tank.


^This is spot-on

 

[whatnext]

+2. I would highly recommend that it also outputs 220.

This past summer, in California, they were turning off power to prevent fires during high wind events. My son was able to buy a quality 2.2 kw inverter generator. However, it doesn't output 220 which he needs for a septic pump. Not sure what his plan is. Maybe get a 2nd generator that does 220 and have 2 units to spread the load around his property.

 

[spasm3]

The HF 4370 was the smallest unit i found that that was 220v. HF has a 4000 unit that is 220v but it is an older model and has more fuel consumption than the 4375.

 

[Exhaustgases]

Most important you don't want to burn out the well pump. If I was choosing a generator, and also concerned about fuel consumption. I'd have small and big. I'd use the big when needed and run normal stuff on the small. Big would be 35KW at least, I have had no luck running a small 1 HP pancake compressor on a 5500 watt generator, its the starting current that goofs things up, and with a 2 hp well pump I know from experience a 10kw would run it, but you want nothing else drawing from it. Don't be skimpy with a generator KW if you have motors to run. Lights and electronic things take very little power to run, electric water heaters stoves refrigerators take more. Most well pumps are along way from the power source, there is a power loss in the feeder wires, and of course the starting current. Sorry a 2000 watt generator is not going to work good on a 2 hp, well pump and if there is any sort of initial load on the motor starting current goes higher yet.

 

[whatnext]

Yeah, seems the collective experiences cited is that for starting current on pump motors one needs closer to 10kw and to limit other loads while starting the pump also. So 7.5kw seems to be the min one can get away with if a pump is in the picture.

Side note: my old 5kw generator surged heavily when my neighbor plugged his sump pump into it but my whole house forced air furnace motor doesn't bother it. Does it have a soft start feature?

 

[spasm3]

You must have some deep wells with big pumps. Mine is 150-180ft and i have a 1/2 hp submersed pump. My 4375 unit seems to run it fine.

Basically i have a refrigerator, 1/2 hp well pump, and a think its a 1000watt 110v furnace fan to run. I don't know what the natural gas igniter pulls though. Plus a few led lights.

The hard part is knowing whats on when the power goes out, before you crank up. So i turn off the well pump and the furnace. Get the power on the house, then turn off the extra lights , all the extra loads,the garage refrigerator, and the small wine cooler , before turning the furnace on.

Then i turn on the well pump as needed. I have run the well pump with the furnace, but i prefer not to run them together.