50 amp generator to a 30 amp transfer switch

[begreen]

The GP17500E is going to go through about 16 gallons of gas to run 10 hrs. If your power outages are like ours (up to a week long) then I would consider a backup to the backup that sips fuel. Then run the house like a boat. Only run essential loads. For us this is refrigeration and freezer. Anything else is gravy. Usually we can also run some lights, computer and tv. In comparison our genset goes through about 1.6 gallons in 6 hrs.. During an extended outage it gets run 2 hrs in the morning and 3-4 hrs at night.

Or get a proper whole house propane genset and put it on a big tank. If you have natural gas, even better. This is an 8KW propane or natural gas unit that will cover most loads.
(broken link removed to http://www.electricgeneratorsdirect.com/Images/Generac-Guardian-6237-Standby-Generator/i10669.html)

 

[ResLur]

Our highest power bill this summer (all electric) was just over $153. However, once you start adding up the watts, for the devices you want the run, it takes 10kw to 12kw, especially for heating and cooling.

Concerning the defective 15kw generac, a generac service representative indicated today that it is mostly likely a bad voltage regulator, and that the generator should be returned immediately. He knew right away, without a lot of explanation. So it must be a common problem for this machine. We are thinking about trying the 12,500 Powermate next. Please keep in mind that a company the size of Generac can encounter faulty parts and workmanship at any time our the company's production history. I just wish it had not happen to us.


Take care,
Larry

 

[ResLur]

You are correct, about 10 gallons for 10 hours. It is not uncommon for us to loose power for several days (Hurricane Irene, 7 days, 1/2 hour). The important devices for us are well pump (lush), heating and lights. We do not keep a lot of food in the refrigerator due to the unreliable power situation in our area (we are at the very end of the power circuit). When the power is out, most of the time Karin and I are at work during the day. So we only require a generator for a few hours each night. We considered the whole house generator ($9,000-two quotes), but I would not feel comfortable leaving the house with it running. By the way, propane is not cheap, and could easily cost you several hundred per week. That is our reasoning, but I certainly understand your reasoning. Thanks for the comment. By the way, for our setup, about $3,300 ($2100 for generator, $1,200 installation/parts)

Take care,
Larry

 

[begreen]

All devices don't run simultaneously. There is no need usually to size a generator for the maximum possible load. You can switch off and cycle to conserve power during an outage. For example, don't use the oven and turn off the hot water unless you need it. What is your heating source?

Personally I wouldn't use a contractor generator to run a house. There are too many electronics in today's home that want fairly clean power. Unless you have a serious load, a 6.5kw Honda generator is what I would consider in gas. It will easily handle the well. The whole house propane generators do not have to run on automatic start. That is your option, it can be run in manual mode if preferred. FWIW our propane is exceptionally expensive. But it is a good generator fuel because it doesn't go stale like gasoline can. And during an extended outage it is typical for our gas stations to be without power too. All things to consider for emergency power.

 

[ResLur]

All devices don't run simultaneously. There is no need usually to size a generator for the maximum possible load. You can switch off and cycle to conserve power during an outage. For example, don't use the oven and turn off the hot water unless you need it. What is your heating source?

Personally I wouldn't use a contractor generator to run a house. There are too many electronics in today's home that want fairly clean power.

We heat/cool with a 2.5 ton heat pump. But I recently installed a mini split system that requires 1/2 the wattage. I will certainly consider your comment.

Larry

 

[ResLur]

We heat/cool with a 2.5 ton heat pump. But I recently installed a mini split system that requires 1/2 the wattage. I will certainly consider your comment.

Larry

Begreen, I just noticed that you are a moderator. Thank you for the site, and taking the time to moderate.

Larry

 

[begreen]

We heat with a heat pump as well, though once it gets 45 or below we heat mostly with a wood stove. Our 3 ton heat pump can run on a 25 amp service, but that is mostly for starting current. When running it is more like 16 amps. As you noted mini-splits use even less power. In your case to run on a smaller generator of say 6.5KW it would take turning off the heat while raising the well pressure. Once that is done, turn off the well pump and turn on the mini-split. A 10KW system would not need much load management but will use more fuel per hour.

PS: I added a few more thoughts on propane to the previous comment after you had posted.

 

[ResLur]

We have a 5000kw (6250 peak) generac generator that we used for years for the well pump and lights/refrig; however, it will not handle the mini split; which is strange. It transfers power to the house via a Reliance Transfer Switch.

Lowes pickup the 15kw generator this morning that was defective. We have decided to go with a 12.5kw Powermate portable generator. It comes with an automatic voltage regulator, which hopefully, will provide some measure of protection for home loads.

Take care,
Larry

 

[fbelec]

when running heat pumps or air conditioners it's not the running amps you need to worry about it's the start up current. if you look at the specs plate on your compressor outside there will be running load and lock rotor current. the lock rotor current is your start up current. 3 ton might be up into 50 to 75 amp load. that's the hard part of running something that heavy on a generator. once you get it to start your ok it will probably run 15 to 18 amps. i have a customer that wants a propane powered generator but has heat pumps a 5 a 4 a 2.5 and a 3 ton units they are all geothermal. the 5 ton draws 125 amps on start up. they couldn't get a generator big enough to run that house. ductless splits seem to start easier than regular whole house air conditioners. begreen have you run your heat pump on a generator? and if so how many watt gen was it?


frank

 

[begreen]

No I haven't. It looks possible with our 4Kw generator, but I haven't tried. It's a contractor generator so I don't want to risk frying its electronics with dirty power and we have the woodstove as a more practical heating backup.

 

[maple1]

I can power our house in an outage on a 3kw inverter genny.

Power to spare and sipping of gas - but, we only have a shallow well 120v pump. And we don't use the big things like stove & dryer, of course. Even still, we can get by for a few days with very little well pump useage using water from a barrel in the basement that catches condensate from our HRV to flush the toilets. Our heating system uses very little juice, just a couple of circ pumps - and it can deliver heat with no power by convection with closely monitored operation. The main things to keep juice to are the fridge & freezer - everything else is not what I would call essential, and is maybe periodic at best.

Is the mini-split your only heat source?

Here, the things you WANT to run are a lot different that the things you NEED to run when the power goes out - I would have a very hard time keeping anything else in fuel in a extended outage, unless I go to putting in an oil tank and a diesel, or tying to a propane company. Which I am not going to do just for backup power.

But we are all in different circumstances & situations.

 

[ResLur]

Over the weekend I was researching inverter technology, but as with everything connected to alternative power sources, this technology is dependent on batteries (or solar). The inverters are capable of providing sine wave power. I do like the fact that Honda has built inverter generators, but only offer them up to 5500 running watts, and I need at least 10kw running watts. So, it looks like I am going to go with the 12kw Powermate that comes with an AVR. Maple 1, the mini split is the heating source for the sunroom that I built this spring. The rest of the house is heated with two 2.5 ton heat pumps.

One thought relative to the inverter, (thinking outside the box, or just plan crazy) - I was thinking if it would be possible to connect a generator directly to an inverter. The sequence would be as follows: small generator powering an AC to DC converter that would be connected to an 12kw inverter. The point, power grind quality electricity.

One final question, is it possible to discharge and charge a battery at the same time. I am thinking no, as electrons can only travel in one direction at any given moment in time.

Begreen, if you do not mind, where do you live. Wow it gets really cold there.

Take care,
Larry

 

[mustash29]

small generator powering an AC to DC converter that would be connected to an 12kw inverter. The point, power grind quality electricity

The A/C to D/C conversion will waste a bit of power (in heat) and then the inverter process will waste a bit more.

is it possible to discharge and charge a battery at the same time

Yes, your car does it everytime you run it. Battery supplies the loads and the alternator is charging it at various rates, based on what the voltage regulator tells it to do.

 

[ResLur]

Success - Finally - The 12,500 Powermate arrive Sunday morning. My Electrician tested the generator today (before plugging into the transfer switch), and it checked out okay. Connected the generator to the transfer switch and we turned on the breakers one at a time. I am able to run the following without placing a lot of stress on the generator (all at once):

Mini Split HVAC
Kitchen Lights
Bedroom Lights
Well Pump
Water Heater
Two TVs
Microwave
Frig.

As you may remember, this was a one month project that turned into 5 months because the first two generators were defective. I am very, very relieved that it is over. And I extend a Thank You to each one of you for your ideas and thoughts. What a nice group of individuals.

Take care friends,
Larry

 

[jharkin]

I know you already bought and installed it... but for the money you likely spent I wonder why you didn't instead buy a smaller inverter generator and spend the rest of hte money to install a wood stove/ insert or even pellet stove to take the heating load? For the same initial investment you would end up with a more robust solution, more flexibility and significantly lower operating cost. (as it seems the heat was the only thing you needed more than 5kw for).


Oh and expanding on a comment upthread.. in a fixed backup generator the neutral and ground should NOT be bonded at the generator. By code the generator may have its own ground rod but the only place the neutral and ground would bond are in the service panel.

 

[ResLur]

First of all, we would never install a wood heating system in our current house, as it would not be compatible with the style of house and they tend to be messy. (No offense intended, please). Concerning inverter generators - this is a new market and Honda seems to have the best technology at this time. A 5000 watt Honda would cost approximately $3,600, when we paid approximately $2,100 for the 12,500 watt Powermate. I have another $1,200 in the 15,000 watt transfer switch and installation costs.

The 12,500 watt Powermate is able to handle all the loads mention above with very little stress on the genny. This saves gas and wear and tear on the Powermate.

Thank you for your comments and suggestions,
Larry