Generator

[RockyMtnGriz]

The three generator solution is similar to the two saw solution. Not a bad idea at all. Redundancy for break downs and better fuel consumption by matching the loads are great benefits.

That 650 is tiny though. Must be a real fuel sipper. My version of the fuel sipper is the 2500 suitcase inverter that’s really 2000 continuous output. 30 hours per bbq propane tank.

So you're telling me I need to get rid of two of my saws ?

Yeah, some redundancy in this area is a plus for my situation, though I've never had a breakdown. I wouldn't have the 650 if I hadn't inherited it. Something at least 1000w makes more sense. But the sound level and fuel consumption are great. The biggest redundancy plus with it is I can easily keep it in my just above freezing garage, not my unheated gen shed. I haven't had the problem yet, but if the Yamaha and the 8000w tank ever got too cold to start, I could use the 650 to thaw one out.

Life was a little better watt-wise before the Kuuma, because oddly though the blower on the Clayton drew more running watts, the 650 gen would pull the startup surge. It won't pull startup for the Kuuma, so if it's cold, now I can't use the 650, which was nice to leave silently running overnight. The Kuuma forced me to buy the 3000 Yamaha, which if I didn't already have the other two, is probably all I would have. It's quiet, just not quite as quiet.

Propane would be awesome from a fuel management perspective, but propane starts to get a little twitchy around -40, and a portable tank of propane gets troublesome at temps higher than that, so I'd probably want to be dual fuel, and that doesn't really solve the rotting gasoline problem, but it would reduce the volume I'd have to keep on hand.

I don't know how much the 650 really saves on fuel over the 3000 because a bigger gen has to run every 8 hours or so to keep the fridge happy, and there's usually something else that needs to be powered up occasionally also. Plus, if I've got the 3000 running, I'm lazy and just leave all the breakers on, and go about life as normal, so I use more juice, thus I've never really been able to tell.

Most of our outages happen this time of the year when the ground is soft from snowmelt and the trees fall over. But it's the ones that happen in February that make backup power extra valuable.

 

[xman23]

i have the 2000 watt gas Champion sine wave inverter. 110 VAC. For me the small size is fine. Good fuel consumption. I pull the main breaker and back feed both legs. so. It's all setup ready to go in minutes, with switches and extension cords. Fridge starts and runs. I think my air conditioner alone would work to. Without the fridge on, I can run every light in the house.

But no 220, so no grinder pump, range, dryer, water heater and electric heat. The wood stove has got us through a few 0 degree nights without power.

 

[peakbagger]

And of course there is overkill Hidden under the panels are 52 KWH of batteries and a Kubota backup diesel generator with a big fuel tank. It is plugged into a generator panel in the house.

 

[begreen]

My version of the fuel sipper is the 2500 suitcase inverter that’s really 2000 continuous output. 30 hours per bbq propane tank.

That's about the same as our genny. Have you run the generator from full BBQ tank to empty? I am wondering what our runtime will be in hours on a full tank. I have the spec, but the Yamaha has an economy mode that matches the load and of course loads like refrigeration vary over time so I am not sure what is the actual runtime.

 

[Highbeam]

That's about the same as our genny. Have you run the generator from full BBQ tank to empty? I am wondering what our runtime will be in hours on a full tank. I have the spec, but the Yamaha has an economy mode that matches the load and of course loads like refrigeration vary over time so I am not sure what is the actual runtime.

Don’t they all have economy mode? The 30 hours per 20# tank is the advertised runtime at 25 or 50% load (crs). I don’t run gensets overnight so I’ll never know how accurate that is. The champion is apparently a Yamaha clone so we may have the same engine.

My home microwave is plated at 1450 watts so that puts a real hit on it.

 

[begreen]

It's popular now, but some don't have that feature. Our old genset didn't. Our generator has an hour meter, so I suppose I could track it cumulatively, but quite frankly we haven't had a week-long outage for a decade now and I am not wishing for one.

 

[ABMax24]

For gasoline fueled inverter Generators I've found that using 1 liter = 1kwh to be a good metric. Most Inverters seem to operate in the 9% to 12% efficiency range at about 25% load, and around 15%-19% efficient at full load. In theory there is a range in between 25% and 100% load where you'll achieve over 20%, but that's not a good number to plan for. Dropping below 25% load on the generator decreases efficiency considerably, very little percentage of the fuel generates electricity while the parasitic losses of the engine idling are still present. 1 liter to 1kwh assumes 11% efficiency which is an easy number for emergency use planning.

In the middle of winter 10kwh per day will keep my fridge cold, the lights on, and the furnace motor running. In an emergency I wouldn't likely run the generator at night, to reduce noise and save fuel, which should keep me above 25% load on my 3100 watt unit. I almost always have 40 liters of gas on hand in cans which should get me by for 4 days. I also have a siphon hose and generally have at least another 30 liters remaining in my boat in the garage, and possibly 20 liters or more fuel in my snowmobile. I wouldn't have to try very hard to go a week without electricity without any extra emergency planning.

For you that are confused with metric, there's 3.78 gallons in a liter, so 3.5kwh per gallon would be a very safe number to use.

 

[begreen]

For you that are confused with metric, there's 3.78 gallons in a liter, so 3.5kwh per gallon would be a very safe number to use.

Typo there, 3.78 liters in a gallon.
Is the kwh equivalent off by a decimal? Online it says that 1 gallon of gasoline = 36.60 kwh.

Convert gallon [U.S.] of automotive gasoline to kilowatt-hours - Conversion of Measurement Units

Do a quick conversion: 1 gallons [U.S.] of automotive gasoline = 36.6 kilowatt hours using the online calculator for metric conversions.

www.convertunits.com

The online calculator says that 1 gallon of propane = ~28kwh. If so, theoretically, then at 25% efficiency I would get about 7kwh and at 20% efficiency about 5.6 kwh. Does that sound correct?

Convert gallon [U.S.] of LPG to kWh - Conversion of Measurement Units

Do a quick conversion: 1 gallon [U.S.] of LPG = 27.988288458333 kilowatt hours using the online calculator for metric conversions.

www.convertunits.com

 

[ABMax24]

Typo there, 3.78 liters in a gallon.
Is the kwh equivalent off by a decimal? Online it says that 1 gallon of gasoline = 36.60 kwh.

Convert gallon [U.S.] of automotive gasoline to kilowatt-hours - Conversion of Measurement Units

Do a quick conversion: 1 gallons [U.S.] of automotive gasoline = 36.6 kilowatt hours using the online calculator for metric conversions.

www.convertunits.com

The online calculator says that 1 gallon of propane = ~28kwh. If so, theoretically, then at 25% efficiency I would get about 7kwh and at 20% efficiency about 5.6 kwh. Does that sound correct?

Convert gallon [U.S.] of LPG to kWh - Conversion of Measurement Units

Do a quick conversion: 1 gallon [U.S.] of LPG = 27.988288458333 kilowatt hours using the online calculator for metric conversions.

www.convertunits.com

Yeah I see that now, should be 3.78 liters per gallon. I was using 8.9kwh per liter for my numbers.

That sounds about right. I'm just skeptical that you will ever see above 20% efficiency in real life use however.

I read a post once somewhere about a guy using an old single cylinder diesel lister engine to power a generator for his off-grid home. He has done countless hours of efficiency testing, and running the engine at 600 rpm the peak efficiency he saw was 22%, and that was at a pretty specific generator load while charging his batteries.

Not that a lister engine is the epitome of efficiency, but it seems most small engines have significantly lower efficiency than many of their larger counterparts.

 

[Highbeam]

22% vs 20 with a modern inverter is way better than I thought for the inverter. Not to mention diesel vs gas. Those listers are huge and with exposed belts, hand starting, probably illegal due to emissions rules. All for a few percent. Still very cool in a nerdy way.

Loading up a 3000 watt genset to 25% takes about 750 watts which is easy to hit for a short while but my refrigerators only need about 100 watts so my 3000 watt genset is typically under loaded during emergency back up power use. The little 1800 watt continuous rated lunchbox genset is much easier to keep in that 25-75% sweet spot range.

 

[ABMax24]

22% vs 20 with a modern inverter is way better than I thought for the inverter. Not to mention diesel vs gas. Those listers are huge and with exposed belts, hand starting, probably illegal due to emissions rules. All for a few percent. Still very cool in a nerdy way.

Loading up a 3000 watt genset to 25% takes about 750 watts which is easy to hit for a short while but my refrigerators only need about 100 watts so my 3000 watt genset is typically under loaded during emergency back up power use. The little 1800 watt continuous rated lunchbox genset is much easier to keep in that 25-75% sweet spot range.

IIRC that guy was running a synchronous AC generator on that Lister (could have also been a Listeroid, the Indian made clone) of unknown quality, I wouldn't be surprised if there is 25% loss in it as well. There was also the belt drive system to bring it up to 1800rpm for 60hz power which would incur losses.

The original Listers were decent for fuel economy in their time, but not exceptional by modern standards. The Listeroid clones were sold up until about a decade ago, many off-griders bought them for simple, reliable power generation. Until the EPA caught on and the importation of those engines ceased.

For reference doing the math from the tables in the ECM of my 2014 6.7 Powerstroke it nets 28-29% efficiency in the cruise region, peaks at 31.4% at 2600rpm and 30% load, and gets 27% efficiency at the rated 400hp at 2800rpm.