Sizing Your Generator

[longbarrel]

Actually, you do.

When the pumps run by the city fail, you will have no water.

A generator will do you not one bit of good in the above situation to get water<

 

[actaeon277]

A generator will do you not one bit of good in the above situation to get water<

It does if you have a well.

 

[churchmouse]

It does if you have a well.

We do not have a well but we know where one is...

 

[actaeon277]

We do not have a well but we know where one is...

When I finally got city water, the well is still there, just not hooked up to the city system.

 

[indyjohn]

A generator will do you not one bit of good in the above situation to get water<

You're skimming the thread. If you were reading all the posts you would know the context in which that statement was made.

It does if you have a well.

We do not have a well but we know where one is...

 

[churchmouse]

When I finally got city water, the well is still there, just not hooked up to the city system.

Winner. Do you run it on occasion to keep it clear...???

 

[actaeon277]

Winner. Do you run it on occasion to keep it clear...???

nope. probably should

Comes out rusty even before though.

 

[churchmouse]

nope. probably should

Comes out rusty even before though.

You need to flush it out. Just because.

 

[KLB]

nope. probably should

Comes out rusty even before though.

My well has a lot of iron in it.

 

[Paul30]

I know it's an older thread, but a couple things to add. Last year we lost power and I turned off our main breaker, and ran a double male 12 gauge extension cord to an outdoor outlet to feed the home. I know there is a interlock you can buy that will not allow you to turn on the breaker you are back feeding until the main breaker is turned off. If one isn't going to get a transfer switch, this is a safer way to hook it up to make sure you don't put power on the lines. I really wasn't sure what circuits were on the same side as the outdoor receptacle I wired into, but it turns out most of what I needed was on that side. I even rewired a circuit to that side to make things better. I know the breaker box should be somewhat balanced, but if you can switch a few necessary circuits to the side you are feeding with a 110v generator, you may not have to keep switching what is on an extension cord.

I am a fan of smaller generators for fuel consumption. A battery bank with power inverter for times you want lights and small things but don't want to run a generator. We were out of power for 10 days when there was a ice storm and many with large generators were running out of fuel often. A gallon per hour on a contractor generator runs through a 5 gallon can of gas every 5 hours. If you have a couple 2200 Honda or Yamaha inverter generators, you can couple them with a cable and get a full 30 amps for RV use or your home if wired for it. You are still 110v, but about 8 hours per gallon isn't bad. I was lucky, the furnace ran on gas, and the 110v blower motor was on the circuit I had fed. We had everything we needed on that 110v line, TV, internet, furnace, etc. Even the refrigerator was on it so it would kick up the speed of the generator every now and then. I have a cap you can screw onto the generator that couples it to a boat fuel tank, so that 1 gallon can be gravity fed from a 6 gallon or more tank to keep it running a long time. I opted for 2 smaller generators for portability and redundancy. If one fails I can use the other, or I can loan it to a family member if I need to. If I had a decent electric water pump, I could get a inexpensive water tank like farms use and use the generator to run the electric water pump to fill it at a lake etc. Don't forget to stock extra spark plugs , oil , and fuel filter. Any of those go and you are without a generator. Having 2 of the same model has a 2nd advantage since they share the same parts.

Here is a link to a company that makes generator interlocks for several popular brand breaker boxes. You can't turn the breaker the generator is connected unless the main is off. Cheaper than a transfer switch, and no rewiring required. https://www.geninterlock.com/

 

[dudley0]

Actively looking for better generator. I have a small gas powered old as hell unit. Think it is 1500w. I have used it to control the fridge, blower motor, 110v well and TV.

I know I need a larger unit but have always worked my way thru it. New place has a 240v well so I know to run it I need a different generator. Started looking at the Generac (NG) units. Pricey to say the least. Basically fire and forget tho. But I am getting mixed reviews on service for them. People waiting months to get a tech over.

Looking at the Predator series from Harbor Freight now. They have a 3500w inverter but again it only has 110v options. I can bump up to a 9000w generator and have my 240v circuit. But then it is not as quiet, clean or fuel efficient.

Where we are now power goes out maybe two or three times a year. Not sure about the new place. I know for sure that power has dropped at least twice in three years, but I am not there all the time and my monitoring system is plugging a radio in.

At this time I am not preparing the generator set for mass, long range outage. Just the inconvenient few hours up to a few days worth. I have UPS to help clean the lines for electronics. I need to run the 240v well, the new fridge, blower motor on furnace (if needed), sparse lights, TV and network, maybe the new microwave.

Will work up what my amp draw will be for sizing.

Would running two of the inverter generators be able to provide me with the 240v circuit, or is that a no-no? Of course spending the money on them is now getting up there where I could possibly get a small natural gas unit to take care of what I want. Plus running two that sip fuel might be the same as running one larger unit.

 

[Karl-just-Karl]

I believe pairing generators only increases your current supplying capability, but there are lots of things in this world I have no idea about.

You can make your next generator a 220V unit and make it easy on yourself.

Or...

There are such things for stepping up your 110V to 220V. This turns ugly real fast with inductive loading, power factor and several other things I can't even begin to explain here. If you can find an electrician or a maintenance person where you work, they might be able to help.

There are more solutions out there than just COTS.

 

[KLB]

Actively looking for better generator. I have a small gas powered old as hell unit. Think it is 1500w. I have used it to control the fridge, blower motor, 110v well and TV.

I know I need a larger unit but have always worked my way thru it. New place has a 240v well so I know to run it I need a different generator. Started looking at the Generac (NG) units. Pricey to say the least. Basically fire and forget tho. But I am getting mixed reviews on service for them. People waiting months to get a tech over.

Looking at the Predator series from Harbor Freight now. They have a 3500w inverter but again it only has 110v options. I can bump up to a 9000w generator and have my 240v circuit. But then it is not as quiet, clean or fuel efficient.

Where we are now power goes out maybe two or three times a year. Not sure about the new place. I know for sure that power has dropped at least twice in three years, but I am not there all the time and my monitoring system is plugging a radio in.

At this time I am not preparing the generator set for mass, long range outage. Just the inconvenient few hours up to a few days worth. I have UPS to help clean the lines for electronics. I need to run the 240v well, the new fridge, blower motor on furnace (if needed), sparse lights, TV and network, maybe the new microwave.

Will work up what my amp draw will be for sizing.

Would running two of the inverter generators be able to provide me with the 240v circuit, or is that a no-no? Of course spending the money on them is now getting up there where I could possibly get a small natural gas unit to take care of what I want. Plus running two that sip fuel might be the same as running one larger unit.

Generacs are a bit pricey, but well worth it if you actually have an outage. Ours is now close to 10 years old, and we've never had an issue with it. Just basic maintenance. When you have a well and septic pump, being without power basically cripples the whole house. We also have a horse barn with animals, which are very hard to try to take care of without power.

We run a 20KW NG with an ATS. Power is out for about 20 secs before the generator kicks on and powers up the house again. The only way I usually know that we've lost power at all is that I have to reset the clocks on the stove and microwave.

 

[cbhausen]

Apologies to all for the pedantry, but I can't help myself. Ohm's Law (for simple DC circuits) is a statement of proportionality (in this case equality) of the current to the electric potential drop divided by the resistance.

​

The relationship P = I*V isn't typically given a name, but it's a result of using Joule's First Law (simplified as P = I^2*R) and using Ohm's Law to substitute as follows to yield a very useful, very simple relationship:

P = I^2*R and V = I*R

P = I*(I*R) = I*V

P = I*V


Where:

P = power [Watts]
I = current [Amperes]
V = electric potential or potential drop (Voltage) [Volts]
R = resistance [Ohms]

From one geek to another...

You must spread some Reputation around before giving it to rhino again.​

 

[Paul30]

For those looking for a 220v option, you need to know your current needs. They do make converters that will take your 110v power and step it up to 220v. If it is built right, there should be little to go wrong with it. I intentionally purchased the smaller inverter type generator to save on fuel. I have been without power for an extended time, and many others were running to the gas station daily to try and keep their box store 6KW generators running. A gallon per hour x 10 hours per day is 2 5 gallon jugs of gas per day. Sure you can run it less, but my Yamaha goes several hours on a single gallon of gas. I may consider a converter myself for the 1 item I have that needs 220v. This one is a 3KW unit, but they make all sizes. A larger one likely isn't going to consume more power but will be capable of putting more out. Of course your 110v generator will need to be able to supply enough power to feed the larger amount of power being drawn.

Several of these are for European power, so make sure the one you select is for United States. I think this one is European but it is an example.

https://www.amazon.com/Regvolt-AC-3...er,&qid=1581781574&s=electronics&sr=1-1-fkmr0

 

[churchmouse]

For those looking for a 220v option, you need to know your current needs. They do make converters that will take your 110v power and step it up to 220v. If it is built right, there should be little to go wrong with it. I intentionally purchased the smaller inverter type generator to save on fuel. I have been without power for an extended time, and many others were running to the gas station daily to try and keep their box store 6KW generators running. A gallon per hour x 10 hours per day is 2 5 gallon jugs of gas per day. Sure you can run it less, but my Yamaha goes several hours on a single gallon of gas. I may consider a converter myself for the 1 item I have that needs 220v. This one is a 3KW unit, but they make all sizes. A larger one likely isn't going to consume more power but will be capable of putting more out. Of course your 110v generator will need to be able to supply enough power to feed the larger amount of power being drawn.

Several of these are for European power, so make sure the one you select is for United States. I think this one is European but it is an example.

https://www.amazon.com/Regvolt-AC-3...er,&qid=1581781574&s=electronics&sr=1-1-fkmr0

It is not absolutely needed to run a genny 10hrs straight unless there are serious issues at hand and then you should be ready for that.
It takes some effort but cycle them. Of course effort is the key these days over comfort.
We have a smaller 2cyxle inverter genny for TV and other critical loads.

 

[dudley0]

For those looking for a 220v option, you need to know your current needs. They do make converters that will take your 110v power and step it up to 220v. If it is built right, there should be little to go wrong with it. I intentionally purchased the smaller inverter type generator to save on fuel. I have been without power for an extended time, and many others were running to the gas station daily to try and keep their box store 6KW generators running. A gallon per hour x 10 hours per day is 2 5 gallon jugs of gas per day. Sure you can run it less, but my Yamaha goes several hours on a single gallon of gas. I may consider a converter myself for the 1 item I have that needs 220v. This one is a 3KW unit, but they make all sizes. A larger one likely isn't going to consume more power but will be capable of putting more out. Of course your 110v generator will need to be able to supply enough power to feed the larger amount of power being drawn.

Several of these are for European power, so make sure the one you select is for United States. I think this one is European but it is an example.

https://www.amazon.com/Regvolt-AC-3...er,&qid=1581781574&s=electronics&sr=1-1-fkmr0

Very interesting. I had not considered a step up transformer for use with a gen set. This opens a whole new world for me. I can get the inverter generator and a step up transformer.

Not sure how well the genny will like the transformer, but I would only need it long enough to power the well pump for short periods.

I will start looking into this option. It makes sense, if the generator is built well enough to handle it. Heck I used step up and step down transformers back when I still had a W2.

Thanks for the nudge.

 

[woowoo2]

Very interesting. I had not considered a step up transformer for use with a gen set. This opens a whole new world for me. I can get the inverter generator and a step up transformer.

Not sure how well the genny will like the transformer, but I would only need it long enough to power the well pump for short periods.

I will start looking into this option. It makes sense, if the generator is built well enough to handle it. Heck I used step up and step down transformers back when I still had a W2.

Thanks for the nudge.

To make 10 amps on the 220 volt side, you need 20 amps on the 110 volt side.
Plus losses inside the transformer.

 

[dudley0]

Started reading up a little on the topic of well pumps. I am not on site to measure at the new place right now, but the start up amperage will be a no go for the little genny and step up x-former it seems.

I just don't see how the 3500 watt inverter generator will handle the inrush current from a 240v pump.

That being said I am back to looking at a larger (gas sucking) genset, or the whole house natural gas version.

 

[churchmouse]

Started reading up a little on the topic of well pumps. I am not on site to measure at the new place right now, but the start up amperage will be a no go for the little genny and step up x-former it seems.

I just don't see how the 3500 watt inverter generator will handle the inrush current from a 240v pump.

That being said I am back to looking at a larger (gas sucking) genset, or the whole house natural gas version.

I see to convenience of the whole house natural gas unit. But the NG supply as to be intact for it to work. It takes electricity to move the NG to you know. It is not a stable if the grid goes down for any serious reasons. When the grid fell out on the east coast some years back and cascaded through several states they had NADA. Nothing. No water/NG/power. Nada.

The local water Co. Has diesel pumps but they drop out when the tanks run dry and even then they are limited as to supply volume. Same with you NG supply. It take power to run the supply loop.

Just something to consider.