Now that I'm more awake, I see I made some errors in my previous post. Looking at the Honda generator specs, you are NOT 2x more efficient at 1/4 load, you just get roughly 2x more runtime. If you calculate it out, you are actually about 2x more efficient in terms of energy/gallon running it at full load.

So what this means is that the advantage to a battery/inverter setup changes. You will probably not see much of an advantage under small, constant loads (like a continuous 50W lightbulb). Either way you are using a set amount of energy, either straight from the generator or from the battery bank. Using the generator, you are operating at a less efficient part of the power curve, so you waste gas there. However, using a battery bank will allow you to run the generator at peak efficiency (full load), but any gains in efficiency will probably be offset by the ineffeciency of the battery/inverter setup. Of course this all depends on the charging efficiency and inverter efficiency, I'm using an estimate of about a 60% efficiency for those types of systems. Under those conditions, I don't think you'll see much of a gain.

Where your idea will really shine is during intermittant loads. If you're running a few lightbulbs continously, and need to power a pump, refrigerator, A/C, only occasionally, then you will see an advantage. If we assume your peak load is about 5kw, instead of needing to run a large 5kW generator continously to power only 100W most of the time, you can run a smaller 500W generator to power the small loads and use the batter/inverter as a buffer to handle the peak loads. Then you will see the efficiency gains from running a smaller enginer rather than a larger one. Again, this all depends on your continous and peak loads.

These are all assumptions and rough calculations, so I wouldn't put a whole lot of faith into it. I'm just rambling off the top of my head.

Raspy, you are describing exactly what I'm trying to. Thanks.

AC at a 120V is hard for me to describe. 20V at 5amps is a LOT from my usual perspective. :P Silly little electronic bits.

And I think that intermittent loads is what most of us who have a household generator have. We have them when the lights go out, and that's about it.

What kind of loads to people put on thier gennies when they are using them? Not contractors, but house hold usage. If we can show a need, something like this might get built...

From memory, my folks would be:
5-8 bulbs in the 50-60W range
1 spotlight bulb, not sure of the wattage, on a motion sensor
water pump
fridge and deepfreeze

And that's about it. Maybe a television, but thats unlikely.

Personally... I've got a camp stove, I've got batteries, and no place for a generator. No electricity, no big deal. Unless BSG is on and I'm missing it, then there might be casualties. :P

I originally bought mine to run my well pump when the power went out. Now that we are on county water, the only time I start it up is when the power goes out and my sump pump is running like mad. It is absolutely amazing how fast the water level rises in my basement when the power goes out during a storm.

When I installed the switch box in the basement, I hooked up the well pump to two switches, the sump pump, and the kitchen wall sockets. This kept me in water, the basement dry, and I could run the toaster oven / coffee pot / electric skillet / refrigerator / etc. I really need to rethink what is hooked up since the well pump is gone and I have two extra circuits available. I had a marine battery & inverter to run the wood stove fan, but should probably look at adding that circuit to one of the switches.

Dragging the gen set out and hooking it up is a pain, especially when the weather is bad. Dragging it through 10" of snow to hook it up......... It only gets hooked up if the basement is in danger of flooding. Otherwise, I can live without it via other backup means.

The system that I use for my shelter option:

The generator will be run 2 times per day (for 2-3 hrs) to run the refrigerator & freezer after I break food out for the next 12 hr period. I'll also recharge my batteries during that same time.

I use a 300 watt invertor to supply battery power for the T.V, computor, cable box, & lighting during the majority of the time. No, I don't run them all at the same time 24/7. If EMP hasn't already destroyed the electronics, the plan is to make periodic checks for news, Civil Defense announcements, and weather reports; and run some lighting.

I also have a bicycle powered magneto that will put out 110VDC to recharge batteries.

I am playing with an anemometer to trickle charge the batteries. It will probably only be practical for recharging the small dry cell batteries.

My biggest problem at the moment is to keep my shelter cool in the summer months.

What about just putting a large-ish UPS[1] on the generator output? Get a higher-end UPS that will tell you the state of charge, and run the generator as needed.

eg: http://canadiantire.com/browse/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524443289558&FOLDER%3C%3Efolder_id=1408474396673606&bmUID=1182542683289

Alex

[1]Uninterruptible Power Supply: Typically used by people who have experienced the sinking sensation of watching a 10-page document disappear when the computer abruptly dies in a power failure, and who are seeking to avoid feeling that sensation again.

A little side note about rechargeable batteries: They have a limited number of recharge cycles. After a couple of years living in the woods you'll realize that your batteries wouldn't hold the charge anymore...

There are much more serious solutions for storing the energy do exist. The fly-wheel systems for example (the best if you're considering building of a concrete bunker).

Hope it's OK to revive this old thread...

I just bought a Honda EU2000i generator for my work, and I also like the idea of having it available for emergency service similar to what ironraven is looking for.

It's truly an incredible machine, and the more I learn about it, the more impressed I am. (There's a yahoo user group dedicated to only this model).

This unit seems to be the most practical method for providing intermittent fairly large power needs (fridge, etc.) and also coast along providing minimal power with minimal fuel use the rest of the time. At full rated output of 1600w (it surges to 2000) it uses its 1.1 gal of gas in 4 hours. When you're not using it full blast, it throttles way down, and uses its 1.1 gal over the course of 15 hours. At $3.20 a gallon, that's 23 cents an hour. It's all handled automatically, and provides the power through an inverter, so it's super clean and stable power.

I brought it home, and called wife outside to hear me fire it up. She didn't want start it, for fear of waking napping kid with nearby open window. (We were talking in hushed voices for that reason.) I started it anyway, and she was duly impressed. It then it sunk in we were still talking in our hushed voices, and could still hear each other perfectly over the generator running under full load at our feet. So to make a long story short, it's a quiet little sucker. Basically a loud hum.

FWIW,

Dave

No doubt Honda and Yamaha are the best portable generators ever made.

That's not entirely true. A given generator will have a minimum running fuel consumption at idle, but generally more fuel is used under loaded conditions. If this is not the case for your generator you should investigate its throttle settings. Systems designed to incorporate battery storage capacity into your home electrical system are commercial available (http://www.oksolar.com/abc/solar_systems_sta.htm) or you can put one together yourself with a charge/genset controller, interter, and a battery bank. Just get ready to fork over lot of cash...