Generator 5000watt vs 6800 watt

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rjundi

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Hello,

Unfortunately where I live the power goes out often and we lose everything including well water. I also work from home.

I calculated some loads:

Boiler Oil Burner 5.7 AMP + ~2.3AMP circulators ~1000 watts
Well 6 AMP x 220V = 1320 AMP
Fridge 5.7 AMP = ~700 Watts

Lights are low due to CFL and likely a Cable Modem/Router/Laptop charger.

Will 5000 watt do it or is 6800 watt way better? It is a difference of nearly $300 in purchase price.

Lastly any thoughts of a Yamaha small engine vs Subaru small engine??

Thanks in advance
 
Originally Posted By: rjundi
Hello,

Unfortunately where I live the power goes out often and we lose everything including well water. I also work from home.

I calculated some loads:

Boiler Oil Burner 5.7 AMP + ~2.3AMP circulators ~1000 watts
Well 6 AMP x 220V = 1320 AMP
Fridge 5.7 AMP = ~700 Watts

Lights are low due to CFL and likely a Cable Modem/Router/Laptop charger.

Will 5000 watt do it or is 6800 watt way better? It is a difference of nearly $300 in purchase price.

Lastly any thoughts of a Yamaha small engine vs Subaru small engine??

Thanks in advance


6800. Startup power, and it's better to have more and not need it, then to need more and not have it. As far as engine, either Yamaha or Subaru are great. Have you looked at the higher end Generac units?
 
Originally Posted By: simple_gifts
Did you factor in the startup draw for the electric motors?


I understand that doubling AMPS is good way of determining startup with nothing else. That puts me at 6000 watts which apparently is "starting" power of the 5000 watt unit I was looking at. Not sure how often this would happen though starting all three motors at once except if I left all circuits on at startup of generator?
 
Are you sure the well pump is only 6 amps at 220? Seems weird they'd wire it for 220 but not draw that much power.

If you have a holding tank you could run the well and fill a bathtub, then shut it off and run everything else and have a little reserve in the tank.

However if you have the extra power you can take a shower after getting all gassy/exhausty and maybe even do laundry.
lol.gif
 
Originally Posted By: simple_gifts
Did you factor in the startup draw for the electric motors?


You bet. A frig may run on 500 wattsbut the start up may draw 2000watts. Also your motor on the boiler will draw a lot of watts on start up.
 
Other things to consider:

The 5000 watt unit is more compact if space is an issue. It will be based on a "small block" engine (think 4-6 hp size, 3/4" shaft).

The 6800 watt will be based on a "big block" (8-13 hp, 1" shaft) and will be heavier if that is an issue. It's the main reason for the increase in cost.

The larger unit is more versatile, obviously it could replace the 5000 watt unit but not the other way around.
 
I think the smaller engine might be more efficient. You really want to run y our well pump selectively (IMHO). You can do the same with the fridge.

These things are really not "set it and forget it" you will probably find a several drop voltage when a major load kicks in.

Also these things eat seriously gasoline when you have loads.

Consider buying something like this to insure you have good voltage.
...TF8&index=0


I guess this stupid board can't display imagtes...what else is new.
18.gif
 
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This board can't do images with question marks in the URL.

My kill-a-watt meter does NOT agree with my generator. I get 60 hz at 127 volts but if that goes off by more than a couple percent the Kill-a-watt just freezes up. Odd because you think of it as a power quality meter-- just a poor one.

I wound up splicing an old computer plug on a $2.99 harbor freight voltmeter. I have governor issues on my 1977 briggs and volts are an adequate a way of diagnosing (adjusting). Dumb motors that make life liveable do well with variable inputs as long as you get them between 105-145 volts (Really!)
 
Originally Posted By: eljefino
This board can't do images with question marks in the URL.

My kill-a-watt meter does NOT agree with my generator. I get 60 hz at 127 volts but if that goes off by more than a couple percent the Kill-a-watt just freezes up. Odd because you think of it as a power quality meter-- just a poor one.


There is a lot this board can't do.

I have used it frequently on my generator and even if the rpm's are way off it still works. weird. Well I'm not sure about the rpm. I only care about voltage since that is the proof of the pudding and that doesn't freeze.
 
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I will go with the larger. I am not excited about the larger size/weight given where it will be stored and hookup is.

However less worry. I have heard from everyone go for the bigger one.

Thankfully my father in law gets a 10% military discount which will take away about $90 of sting of this. My wife is hounding me as she goes crazy when power is out.
 
I would personally do a bit of research on this. What factors are important to you ?
1. Fuel Consumption.
2. Run Time.
3. Continuous duty cycle, vs rush current.
4. Power of engine correlating to watt rating (also see #1, use 746 watts per HP).
5. Factor on Voltage Droop. If all of these devices turn on at once, worst case scenario. Then assuming a rush current of 2X normal current, and a #8 Copper cable. You'll have Vdrop of 0.0291166 Volt/Foot. If this turns out to be significant then most motors will burn out trying to run at low voltage. Since the magnetic fields don't have enough energy to be formed properly.

My main point here is that DON'T plan to just set it and forget it like you would on normal power. Plan for each device to come online at separate times. Your devices and generator will thank you for it. If you plan for the devices to be "Staged" to come online and would like more margins for a greater number of devices then I would choose the 6800 watt. Otherwise I would choose the 5000 watt.
 
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Trust me, we got stuck in a power outage for 4 days last year and I got the biggest generator I could find on short notice, 6500 surge and 5500 nominal. This is one of those deals that bigger is better. Less hassel.
 
We had an ice storm here awhile back and I ran my entire house off a 5kw gen set for a week.

I think if you are careful and manage (stagger) start up loads properly, you can do it comfortably on a 5kw set. My 5kw set was (is) 10hp so it can handle start up surges past 5kw, iirc, it was rated for 6kw surge.

We have a nautral gas furnace, but I set a lot of the oil filed radiator heaters around as they don't use a lot of energy once they are hot, and kept the fireplace going for heat.

It is really helpful and convenient if you have a means to disconnect the mains and connect the genset to your load panel in place of the mains, but for safety sake there must be absolutely zero chance of backfeeding the grid.
 
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