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Small Cabin Forum / Off-Grid Living / How to size a new generator
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zorro
Member
# Posted: 29 Nov 2023 03:50pm - Edited by: zorro
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I am not good at this, so hopefully someone can help

I need to replace my generator as it is giving me too many problems now – have replaced the carb, plugs, battery, used “cleaner” etc

It no longer starts on gasoline and was running with Propane – however, even that is now a problem and time for a change I think

Needs to be duel fuel with a 120/240V L14-30R “plug” for connection back to the cabin and remote start

So I need to get a replacement generator……………….but what size??

The generator runs the following items in the cabin;

Water Well Pump – From the manual - 0.5HP/230V/

At full load - 4amps/845Watts
Service Factor – 4.7amps/1050Watts

It also runs hair dryer for when my wife uses it for say 20minutes – say 2000W

And a Vacuum when used – 15 minutes – say 2000W

The 3 are NEVER all used at the same time

So what size of a generator would adequately run the above demands in terms of the starting/running Watts?

My current generator may be too big??? and it would be good to downsize/get a quieter option if possible

Current - 7500 running (Gas)/6750 running (Propane)


All of my lights, cell charging, small fridge, TV, etc are run off the solar panels and batteries

Thanks

EDIT

was looking at something like this...........

5250 running - gas
4750 running - propane
Remote start
120/240V 30a socket

Never heard of the make though - but can easily add a 4 year warranty for $120

https://www.amazon.com/PPOXURIO-Portable-Inverter-Generator-Electric/dp/B0BY8HRSPG/re f=sr_1_3?crid=1CRGEH2ZLXTJL&keywords=poxurio+6000+watt+generator&qid=1701292927&spref ix=poxurio+6000%2Caps%2C216&sr=8-3

Brettny
Member
# Posted: 29 Nov 2023 07:29pm
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Really the well pump is the main draw and only thing 240v. How deep is it? You can get prety cheap 1/2hp well pumps that are 120v. The reason I say that is I dont think that generator is actualy 240v and really with out a deep dive the only thing that says 240v on it is the plug type.

gcrank1
Member
# Posted: 29 Nov 2023 07:57pm
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I sized to the biggest anticipated load; ie, the biggest Start Up load and added a cushion of 'more'. And next time I will go a bit bigger even though Ive done ok (I think Im probably just ok as is). I think it might be good to be sized for the two biggest loads at once (mistakes do happen, ask Murphy).
Im thinking that getting a gen is like building a garage, pole building, cabin or cottage.....often not quite big enough.

travellerw
Member
# Posted: 29 Nov 2023 09:41pm - Edited by: travellerw
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The well pump is the big question. Its the "inrush current" (sometimes called surge) that will be your big issue. There are multiple factors that will determine that number (everything from temp to depth of pump). On a standard electric motor running at ground level, inrush current is usually 3 times operating current (4 times is usually used as a "safe" number).

However, some well pumps don't have the space for proper sized capacitors and draw more.

My suggestion would be to see if you can rent a 3500W unit to see if it will run your pump. If so, you can look for 3500-4000W inverted generator which should be much quieter than an open frame screamer! These days it seems the popular flavor is Firman (sold at HD and Costco). They have tri-fuel units that are remote start.

zorro
Member
# Posted: 29 Nov 2023 10:57pm - Edited by: zorro
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Thanks guys

So the well is 410’ deep

If I recall, the pump sits around 150’ as the water height is around 20’ from the well head with really high pressure

At this stage I don’t want to change the pump

Current generator is an open frame Westinghouse - which is terrible to start in the winter………even with light oil

So the link above has the generator running at 5250W on propane, which is my preferred choice of fuel

Would that be big enough?

travellerw
Member
# Posted: 29 Nov 2023 11:24pm - Edited by: travellerw
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Quoting: zorro
Would that be big enough?


Probably... Maybe... I don't think anyone can tell you without have the inrush current data on your pump.

I have never met a generator that is easy to start in the winter (below 0F). Most are splash based oiling systems with carburetor engines (and not advanced carbs). Super hard to start in the winter. However 2 things that can help a lot are
1. A vehicle sized battery with good cranking amps.
2. An oil pan heater (if you can run off your solar for an hour before starting).

If you are looking for a generator that will start like your fuel injected car at 0F, I just don't think it exists.

P.S some huffing juice (carb cleaner or starting fluid) in the carb throat will also get stuff choochin... but hard on a cold, dry engine.

Brettny
Member
# Posted: 30 Nov 2023 05:57am
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Quoting: travellerw
suggestion would be to see if you can rent a 3500W unit to see if it will run your pump. If so, you can look for 3500-4000W inverted generator which should be much quieter than an open frame screamer! These days it seems the popular flavor is Firman (sold at HD and Costco). They have tri-fuel units that are remote start.

Its actualy not that common to find a new 240v 3500w generator and even less common to find a 240v inverter generator. Most are all 120v.

At 400' deep keep the pump you have, it's no simple job to change. I also wouldnt buy anything smaller than a 5kw because of head pressure on the pump.

Steve_S
Member
# Posted: 30 Nov 2023 06:49am
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Quoting: zorro
So the well is 410’ deep

If I recall, the pump sits around 150’ as the water height is around 20’ from the well head with really high pressure

At this stage I don’t want to change the pump


Given that a new 120V Soft Start well pump will set you back a grand - it's not something to do on a whim. Mind you my GrundFos SQ5 is 240' deep, softstart 120V and it is Very Polite to my system starting at 550W and stepping up in 3 stages.

PLEASE - Avoid Off Brand Gennies... I'll give you $3000 worth of Inverter Models that died (King & Energizer branded).

I use Champion Generators (Construction & Inverter) and I start both in deep cold, down to -30C/-22F. Their only BIG Inverter Genny that has 240VAC is here https://www.championpowerequipment.com/product/201175-champion-8500-watt-dual-fuel-in verter-with-co-shield/ Even their 5500W model is only 120V

Brettny
Member
# Posted: 30 Nov 2023 07:44am
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I will mind you that even decent name brand generators arnt with out issues. My 117hr champion 4500w inverter was failing to crank and really hard to pull. The problem started at 99hrs. Turns out the valves where terribly out of adjustment. Even though there maintenance invertval for this is 250hrs.

Nobadays
Member
# Posted: 30 Nov 2023 09:18am
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The generator you linked to shows it's a 120vac, not 240vac. Visually it shows the 30a plug but the info says 120v.

Quoting: Brettny
I will mind you that even decent name brand generators arnt with out issues.


I have a HF Predator 3500, 120v that just turned over 1000 hours and starts fine in cold weather... it was 0°F rwo mornings ago and it fired up with normal about of cranking.

I acquired a Westinghouse dual fuel generator last fall with 2 hrs on it. It now has 12 hours on it and just up and died this summer for unknown reasons. I haven't torn it down yet to find what happened..... yeah even name brand generators have their faults.

gcrank1
Member
# Posted: 30 Nov 2023 09:59am
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The 'Westinghouse' branded gens are not made by the old, reputable Westinghouse; they are made 'offshore' by somebody who likely 'bought the rights' to the name for marketing.
Do not be deceived by branding.

Steve_S
Member
# Posted: 30 Nov 2023 10:04am
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Quoting: gcrank1
Do not be deceived by branding.

No truer words have been said.
Case in Point: Midland Power Inc LLC that owns many labels https://www.midlandpowerinc.com/

zorro
Member
# Posted: 30 Nov 2023 01:09pm - Edited by: zorro
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Thanks for the info guys

Couple of points - I have reviewed the manual for the pump and cannot find any mention of the "inrush current data" anywhere??

In terms of the generator I linked to............now not so sure on the output

The actual 30A outlet says 120/240V

However, I just found a video review from "Gavins Garage" on Youtube

Here is a picture of the generator running - seems to show 242V when using the 120/240 outlet?

The guy was running his full AC in his RV

But it is the usual - seems "too good to be true" scenario - inverter, 120/240V, dual fuel, quiet, remote start, all for $800................worst case is to pay $109 for a total of 4 years warranty from Amazon
IMG_5047.jpg
IMG_5047.jpg


ICC
Member
# Posted: 30 Nov 2023 02:25pm - Edited by: ICC
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Quoting: zorro
I have reviewed the manual for the pump and cannot find any mention of the "inrush current data" anywhere??


What type of pump is it? Some pumps do not have a startup inrush as they are soft start, like Grundfoss SQ.

-izzy

travellerw
Member
# Posted: 30 Nov 2023 02:30pm
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Quoting: zorro
Couple of points - I have reviewed the manual for the pump and cannot find any mention of the "inrush current data" anywhere??


Inrush current is almost never listed, and usually needs to be measured.

The unit you linked to is absolutely 240V, with a standard 240V receptacle. Its says 120/240 because that is how we supply power here in North America. It will be 240V across the hots, or 120V from one hot to one neutral. If your pump has that plug, just plug it in and it will work. Its worth a try for the price.

I have a bit of a different view as we owned an import and repair company for RV products. Generators were one of our main items and we serviced ALL brands. Honda, Yamaha, westinghouse, Champion, Kipor, Boliy ect ect. Many share the same engine (a Boliy muffler will bolt on a Yamaha generator and vice versa). While some of the brands are better than others (Westinghouse sucks) I have seen all of them go 1000s of hours. The Firman brand is carried at Costco and they stand behind it, but I don't think there is a 240V version.

However, I don't know how the other guys are getting them to start in the cold. For us, they all sucked in the cold to start (below -20C). So much so, we never stored any outside as the buggers would have to warm up before we could start them to diagnose any issues. If we didn't have the time, we could usually get them to start with a boost from a booster pack or bigger battery.

zorro
Member
# Posted: 30 Nov 2023 02:42pm
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This is the pump here;

https://www.amazon.com/gp/product/B00SNJ3I5Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF 8&psc=1


Goulds 10HS05422C 4" Submersible Water Well Pump, 10 GPM, 1/2 HP, 230 V, 2 Wire

travellerw
Member
# Posted: 30 Nov 2023 02:54pm
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Quoting: Brettny
Turns out the valves where terribly out of adjustment.


This was a common repair on MANY MANY units. Even big brand names sometimes had that problem.

Another issue when they got super hard to pull over (or if they ripped the cord out of your hand), was the camshaft compression release. There is a small lever that opens the exhaust valve at low RPM for easy starting. The lever would get bent and then not open the valve making it super hard to start. The only fix was to replace the camshaft. Expensive fix as it took more time to tear the machine down than the actual camshaft replacement part.

travellerw
Member
# Posted: 30 Nov 2023 03:00pm
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Quoting: zorro
Goulds 10HS05422C 4" Submersible Water Well Pump, 10 GPM, 1/2 HP, 230 V, 2 Wire


The "Locked rotor" amps for that pump is 19.5A, so 19.5AX240V is 4680W. That is the max that pump will draw even if the rotor was completely locked up. So you should be good with a 5000-6000 sized generator.

zorro
Member
# Posted: 30 Nov 2023 03:14pm
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Thank you

So that generator i linked above is likely too underpowered

5250 running - gas
4750 running - propane

My preferred choice is propane and is piped in for that

Need to keep looking as that was a good potential option

Thanks

zorro
Member
# Posted: 30 Nov 2023 04:03pm - Edited by: zorro
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Ok - found another option

Just need to read some of the reviews and videos online as they seem to be kind of mixed!

https://generatorbible.com/generators/pulsar/pgda70bisco/


And this one here with better reviews but more expensive

https://www.amazon.com/gp/product/B0B9NGJHQT/ref=ox_sc_saved_title_1?smid=A20F50ULGHR LRU&psc=1

Brettny
Member
# Posted: 30 Nov 2023 04:36pm
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Quoting: travellerw
his was a common repair on MANY MANY units. Even big brand names sometimes had that problem

I have a actualy never had to adjust valves on any of the many small engines I have ever owned. Maybe because I was buying used engines?

gcrank1
Member
# Posted: 30 Nov 2023 04:42pm
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Warm em up to start...NO problem, keep it in the sauna, start the stove, let it warm the room up (but Not the humidity part) And the gen, start the gen then use the sauna?

travellerw
Member
# Posted: 30 Nov 2023 05:35pm
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Quoting: Brettny
I have a actualy never had to adjust valves on any of the many small engines I have ever owned. Maybe because I was buying used engines?


Have you checked? You might be surprised how out they can be before you notice. The first indication is hard starting and increased vibration.

I actually got given a very nice self propelled lawn mower this year. I was told it was shot because it was knocking. Checked the valves and they were way out. Adjusted and the "knocking" went away. Kids have been mowing the lawn all year with it. No knocking and never skipped a beat.

Brettny
Member
# Posted: 30 Nov 2023 05:49pm
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I have a sportsman 1kw with 101hrs that sounds like a knock but it's also blowing blue smoke. Generaly the only running issues I have are carb issues.

zorro
Member
# Posted: 30 Nov 2023 07:31pm
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I had considered using this for say 15/20 minutes before running the generator to try to get it warmed up a little before trying to start it in the winter
Capture.JPG
Capture.JPG


Brettny
Member
# Posted: 1 Dec 2023 04:06am
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That seams like a total pain in the butt to me. There are military surpus 5kw units that run at the efficiency of a honda eu2200 and are quiet. I know someone makes a remote start kit for them. But they are diesel. I have started mine in 6*f with just the preheat function.

paulz
Member
# Posted: 1 Dec 2023 10:15am
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Quoting: travellerw
Another issue when they got super hard to pull over (or if they ripped the cord out of your hand), was the camshaft compression release. There is a small lever that opens the exhaust valve at low RPM for easy starting.



Interesting thread, great to have someone on here with lots of experience. I’m familiar with these exhaust lifters from motorcycles, didn’t know some genies have them. I have an old 240v 10 horse Briggs dedicated to the well pump, only runs occasionally to fill the tank. One shot of ether and it’s off and running. Cabin 300’ feet away has its own gennie.

I wonder how much difference gasoline quality/age makes in starting. Does a small engine specific fuel (VP for example) make a difference over automotive pump fuel?

gcrank1
Member
# Posted: 1 Dec 2023 10:50am
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Ime 'better gas' (use Only Non-eth blend gas, pref premium, in something not run often) pops off better.
Those automatic compression releases do go bad so use the old method:
Roll engine up on compression, then just past tdc.
Now when you pull you arent fighting the compression, the flywheel effect rolls the engine around well and it should fire on the next compression stroke.
Btw, I use this trick on my 12yr old elec start lawn tractor that the auto-cr is totally worn out/busted. The battery doesnt have enough beans to fight the cold compression either.

gcrank1
Member
# Posted: 1 Dec 2023 10:56am
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This next may not be totally on topic here but does apply to cold starts.
My snowthrower here in WI sits in a cold shed, and we do get COLD in WI. Miserable to pull start a 9hp!
In prep for a coming snow I will throw a tarp over and have my old 'milkhouse' elec heater under pointed at the engine block for at least a few hours (as well as syn oil). Works great On The Grid.

redwolfguild
Member
# Posted: 1 Dec 2023 11:49am - Edited by: redwolfguild
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I hear a lot of I need and i don't want to do's in this. But if you seek a reliable generator that will run 240v, remote start, easy start when cold, and be reliable the choice is simple. EU7000 from Honda. Yes it is expensive but it ticks all your boxes. Is it cheaper to have 2 Brand X generators - yes it is - will they start as easily as the Honda, well that is up to you to decide.

One thing I did not recall seeing in the thread was how often do you run your generator?

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