Help! Selecting generator....

[mahlers]

Respectfully, I think your Dad's either mistaken or he's got some tuning-up to do on that generator. The 20kW generator I'm looking at will only draw 2.3 gallons of propane an hour at full load and about 1.5 gallons per hour at half load. So, at moderate load and usage levels, a 500 gallon propane tank should be good for at least a month (assuming about six hours a day at full load, and another six hours at minimal load).

Interestingly, at full load with this 20kW generator, the fuel cost per kilowatt-hour is only about $0.14. That's about the same that I pay the utility company. Of course, if you amortize the cost of the generator over it's lifespan, that cost goes way up, but it's an interesting number nonetheless.

 

[JoeR]

Thanks Mahlers! I thought his consumption was too high also, and your numbers sound reasonable. I have thinking about a standby generator with LP since I get too many hurricanes, and when my Dad told me how much his generator consumed it scared me away from LP. I will have to talk to him again Sunday and verifiy his numbers.

Thanks for the response, it set me at ease about LP.


Joe

 

[greenville7491]

According to this wattage worksheet that I have in front of me , you will need a 6500 watt cont./8500watt surge generator. I had the same setup before I upgraded. My generator was a 6500 watt Onan. John

 

[BobRip]

I have a 330 foot well, septic tank pump, 2 refrigerators, freezer, electric hot water and heat pump. (I don't run the heat pump, but use a fire place during power outages) I bought an 8000 watt continuous and 10000 watt surge generator. I think this is a pretty good size for your purposes. You did not say how deep your well is. This make a big difference. Starting the well has been my biggest problem. I actaully had to upgrade the wire size after 9 years because it would not start during Isabell.

A point that nobody has made yet, fuel consumption. A bigger generator will use more gas. Unless your are running your well (which will only run for a few minutes) and your hot water heater, you will probably be very lightly loaded. I tend to turn on one big load at a time using the circuit breakers. We did fine for 7 days during Isabel. Right now you want to ride through the short outages, but believe me when you get a long one, you will want that power. I have also found that to keep a refrigator cold you have to run it about 12 out of 24 hours. These means about 10 gallons a day of gasoline. Also keep spare oil, oil filters, spark plugs and air filters in stock. You cannot get these during a power outage. Also have a way to pump gas out of your vehicles and fill up if an outage is coming. You should also run the generator about every two weeks with a load (I use an electric heater) to keep the windings from absorbing moisture and the engine operational. If you don't plan to do this, then don't waste your money. Sorry for the lecture, but I have seen money wasted on generators by people who did not follow the above advice. One friend had a generator run for four hours and then die from moisture in the windings. It had not been run for 2 years. Good luck.

 

[KiotiJohn]

</font><font color="blue" class="small">( I have also found that to keep a refrigator cold you have to run it about 12 out of 24 hours. )</font>
I was luckier, I only ran my refrigerator for about 4 hours a day and the ice cubes didn't even sweat!
I was using my 4K Onan in my motorhome and used about $50 of gas over the 4 1/2 days I was without power. I did not let it run while sleeping. At that rate, a monthly bill would be outrageous. John

 

[Soundguy]

Might check that setup.. he may have a huge leak.

Soundguy

 

[stonebase]

<font color="blue">I have a 330 foot well, septic tank pump, 2 refrigerators, freezer, electric hot water and heat pump. (I don't run the heat pump, but use a fire place during power outages) I bought an 8000 watt continuous and 10000 watt surge generator. I think this is a pretty good size for your purposes. You did not say how deep your well is. This make a big difference. Starting the well has been my biggest problem. I actaully had to upgrade the wire size after 9 years because it would not start during Isabell. </font>

Thanks Bob, Looks like our set up is similar. Our well actually is around 155 feet deep and we have a Gould 3/4HP 230V pump, I could not find any specs (on web page) concerning the starting load. Another point I failed to mention is that we have a water filtration system tied in to our holding tank due to the high iron content of the ground water and an additional tank that holds a solution that is intermittently pumped to maintain the proper pH balance of the water. I would imagine that I would want to keep these operational during an outtage also, not sure of the load here either.

After looking at the specs of our hot water heater it looks like it is a dual element (80 gallon) model so the load is rated at 4500W upper and 4500W lower but the tag says 4500W total, wouldnt these values be added up to 9000W?

Looks like by these figures that I may be approaching a 10K generator, really wanted to keep it at 7500W if possible. That leads us back to load management. I dont know if I understood this correctly but with the transfer switch I can just select the circuit I wish to run at will? It looks like I could keep the load below 7500 at any given time. Is there any other concerns? Like do any of these pumps lose their prime if they are toggled off and on intermittently? If I run the hot water heater for a period of time how long will that water maintain the temperature, enough to run the shower for a period of time? I guess with a little effort one could survive with the basics available when needed. Any comments are appreciated. John /forums/images/graemlins/cool.gif

 

[Bob999]

<font color="red"> After looking at the specs of our hot water heater it looks like it is a dual element (80 gallon) model so the load is rated at 4500W upper and 4500W lower but the tag says 4500W total, wouldnt these values be added up to 9000W?</font>

Most water heaters, yours included, include an internal thermostat that will apply power to only one element at a time. Therefore, while there are two elements, the total load is only one element.

<font color="red"> That leads us back to load management. I dont know if I understood this correctly but with the transfer switch I can just select the circuit I wish to run at will? </font>

The transfer switch allows you to select where the power comes from--your generator or the utility grid--and locks out the non-selected source.

Some transfer switches include an additional element--circuit breakers for loads. For a transfer switch which has only the single function of transfer you use an existing or new circuit box with breakers for the loads. In either case, you can use the breakers after the transfer switch to control which loads are active.

 

[Fireman_dcb]

stonebase,

Sorry I didn't get back to you sooner - I run the furnace (forced hot air) with NO problems. There is a drawdown when it kicks on, but not enough to cause any problems.

Doug

 

[ByronBob]

Lets look at Amps for a minute here. The generator I have only has a 30amp 220 twist lock plug on it. So at best I can only get 30amps max from the generator. It's a B/S 5500 continuous generator. How many amps will things be?

6amps for the well pump (mine anyway)
The septic pump?? Don't have one but you should know. Maybe 5 amps
Furnace you won't use.....
Fridge and freezer are big draws. You'll have to alternate running those between each other
The rest of the stuff is little on power use.
Microwave??? Jeez it's a hog for power too

A 50amp 220 plug will do you fine but that steps you up to a 7500 watt generator. My vote is at least 7500 watt