I just dropped the price of
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for a wee bit.

 

 

uses include:
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Backup Generator  RSS feed

 
Steve Turner
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Location: Palmer, Alaska
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Hello. My family's homestead in Alaska is off-grid. Our solar array suffices for about eight months, but it's pretty dark the other four! We have explored other alternative energy sources, but none are feasible for our site.
Currently, we charge our battery bank with a pull-start 5kw gasoline generator, but we would like to change to something more efficient, more durable, and with electronic ignition (so our charge controller can fire it when the batteries need charged). Some options we are considering are a Northen Lights 6kw diesel generator (to utilize the fuel oil we have for our backup heater) or a less expensive Vanguard propane generator. We could also get a little Honda with auto start, but I'm leary of gasoline generator's lifespan.

Does anyone have experience with system-controlled generators. How well have they performed? Have they been reliable? Any recommendations?

Many thanks.
 
R Scott
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Location: Kansas Zone 6a
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Many are still cheap generators with electric start controller tacked on. You can do the same thing with a basic key start genny and a homemade computer/logic box (basically just a latching relay to shut off the starter when it actually starts).

One fuel is so much easier, but propane doesn't gel. Propane does liquefy at room temperature at -40 or so, so you lose all tank pressure in the cold. I used to have to set bonfires under my tank when I lived up north--exciting times!

I still vote for diesel if it will be in a controlled environment, like inside a utility building that is somewhat temperature controlled. I do not want to rely on a diesel to start in the cold unless I have electricity to pre-warm the oil and coolant.

How often do you run the genny? daily? weekly? It makes a difference.
 
Steve Turner
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Location: Palmer, Alaska
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In the summer, we run generator about once a month for battery maintenance. By December, it's about every other day. We try to maximize battery life, so not discharging too far is top priority. Having ability for charge controller to start generator at appropriate level of discharge would help guarantee that.

Our outside fuel tank is filled with #1 Fuel Oil; no problems with gel so far in our maritime-influenced winters. We get -10F occassionally, but lows of +10-20F are more the norm. If we get a US$8k diesel generator, it will definitely be in a temp moderated environment, but fuel tank is still outside.

Do you know the pros/cons of available diesel gen sets? Northern Lights are widely available here. Also Kubotas. We may have a line on an old 5kw Lister, but not sure about auto-start capabilities of that one.
 
R Scott
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Lister is what you want if you run the genny 24/7, but not exactly made to interface to a charge controller.

I have never heard of northern lights, mostly cummins/onan or kubota in that size range. I haven't heard anything horrible about any of the water cooled diesels, other than user error (not warming up or cooling down right, wrong size for load, poor maintenance, etc.). Stay away from the air cooled diesels, they seem to be built worse than the cheap gas generators.

You want one with good local service if at all possible. Not just for the service, but as a vetting for the quality of the machine. A good dealer won't carry junk if he services what he sells-he won't be in business for long in a small community if he does.
 
Richard Terrace
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Have you considered natural gas? I've seen some triple fuel (gas, propane, natural gas) generators. In BC natural gas is cheap and it's not going to liquefy on you regardless of temperature. Down side is tanks tend to be much larger and variable availability.

My anaerobic composter produced biogas which I've used for cooking but only as a pet project. I've heard people using in generators but no experience on that
 
Cj Sloane
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Steve Turner wrote:Northern Lights are widely available here.


I think we had a Northern Lights auto start years ago. I think it was Tri-fuel but we used propane only. It did not last nearly as long as we'd hoped. 5 years maybe but I'd have to check with my husband.

*edit* hubby says less than 5 years. Way less.
 
Richard Terrace
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Just thinking..

You are in Alaska .. In winter.. Have you considered a microchp system? In short co generation of heat and electricity. Your heater becomes a generator also.

Marathon engines makes a version. Designed for long term uses and for use in cold climates. Didn't think about it right away because my area isn't cold enough for cogen to be useful

Look up ecogen marathon engines and it should come up
 
Steven Harris
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you said you wanted something more efficient. That was your chief concern, going with a 6KW diesel, and diesel is more efficient, is NOT going to save you money. Having your current 5K gen is not going to save you money. There is something with engines and generators called a TURN DOWN RATIO. This is the ratio from its lowest power output to its highest power output, on an engine this is typically 4 or 5:1. So even if your charger is only drawing 500 watts of power, your 5k generator is still spinning and eating up gasoline as if it was 1k of power. Even if you were drawing 4 watts, its still spinning and eating fuel at 1k of power.

What you want is a smaller generator. The Honda EU1000i and EU2000i are FAMOUS for being reliable, easy to start and LONG LIFE. Go read the trailer life postings and you'll find people who have run the generator for 10,000 to 12,000 hours, with oil changes every 100 hours.... but.. they are not auto start, they are not electric start. Oh.. and if you get one of the Hondas, you MUST get this awesome external fuel tank that will power it for 3 days for the EU2000i. http://vmsales.com
For charging your battery, I'd just go with the eu1000i. If you wanted to start it up in the AM, run the microwave, charge your battery, do some other power intensive stuff, I'd get the eu2000i.

These will be your MOST EFFICIENT use of gasoline. The eu1000i can output max 1000 watts (1kw or 1k) but because its an inverter generator, it has a turn down ratio of 6 to 8:1 rather than 4 or 5:1. So it can spin at 100 watts and give you 100 watts of power... so great use of your fuel.

If you go with an electric start, then your charge controller can autostart the generator, but all of these are a lot larger generators so with the turn down ratio, you'll be burning fuel just to keep the thing spinning. Running a diesel and having your fuel oil tank as a source of fuel, as long as you are getting #2 fuel oil or better, than that is convenient, but it won't be as efficient. Of course it negates the need to lug around 5 gallon jugs of fuel, but again, that vmsales.com exterrnal tank really makes life nice.

Go read the stuff on the trailer life forums... you'll be surprised by the extensive life of the honda generators.

Steve
 
Chris Olson
Posts: 84
Location: Northern Wisconsin
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Steve Turner wrote:Does anyone have experience with system-controlled generators. How well have they performed? Have they been reliable? Any recommendations?


We have lived off-grid here in northern Wisconsin for many years and our generators are controlled by our XW Power System. Frankly, for off-grid life I wouldn't be without automatic control of the generator(s). Properly set up, the power system makes much better decisions on whether or not to run a genset than humans do, and shuts it off when it's no longer needed, which is something humans forget to do sometimes.

We have three different generators, one of which is a diesel. But diesels take too much power input in cold weather to get them to start. So we don't use the diesel in the winter time. We used to have a LPG genset and couldn't keep that running in the winter either. A generator is the equivalent of running a 100,000 BTU furnace on LP and when it gets lower than -30F the tank can't maintain enough pressure to keep it running. After two winters of building charcoal fires under a 500 gallon LP tank, and covering it with black blankets to keep it warm enough to vaporize the gas, we finally gave up on it. And like you in Alaska, due to frost issues, we can't bury a LP tank here.

So for the winter months the gasoline fueled gensets remain the best because they will start reliably at 40 below with minimal energy input for pre-heat. The trick is to set up your system to prevent nuisance starting of the genset (like on inverter load amps), and have it set so that when the generator does start and run it is loaded to 80% of it's rated prime power, or better. That will yield the best kWh/gallon of fuel.
 
Chris Olson
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Location: Northern Wisconsin
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Steven Harris wrote:What you want is a smaller generator. The Honda EU1000i and EU2000i are FAMOUS for being reliable, easy to start and LONG LIFE.]


While sizing the generator properly for an off-grid system is important, I do not recommend inverter-style generators for off-grid use, or on inverter/chargers. While great for camping and RV's etc, they don't have enough surge capacity to power the AC input on a decent-sized off-grid inverter because something as simple as a 'fridge compressor starting that draws 500-600 watts surge when the generator is charging batteries will cause the inverter to disqualify it. Conventional generators are able to "soft start" surge loads like well pumps, refrigeration compressors, etc because they momentarily "sag" on voltage and freq under surge overload. This allows the inverter to keep the genset qualified on its AC input and start loads that no inverter generator can handle.

The other thing is that you can't use the auto-throttle on a EU-series generator feeding the AC input of any decent off-grid inverter anyway because, again, the inverter will instantly disqualify it at the slightest surge load like even a well pump starting. Generators that get constantly disqualified by the inverter are worthless for off-grid use because they spend too much of their time running under no-load while the inverter looks down its nose at the thing telling it to grow some balls before I'm going to let you hook up to me again.

I also find it necessary to tell you that unless you have had extensive experience with full-time off-grid living, you can't make recommendations like that. A generator installation in a full-time off-grid home will see more severe duty in one year than the same generator will see in 10 years in a RV application. They are two totally different animals. Anybody that has lived off-grid long enough has a dead generator collection because they buy the cheap ones first and wear them out in a year. There is a reason companies like Generac and Kohler void the warranty on their residential standby generators if they are used in a off-grid application. The Northern Lights diesel generators in question have a proven reputation for off-grid applications, as does Perkins, Robin, Cummins, Caterpillar, Kubota and a few others.

If I had more of the specifics of the system - size of the battery bank, what inverter is being used, normal daily energy consumption in the home, what types of large loads there are, and whether or not the generator is going to be used for Load Support I could come up with a better recommendation. With an auto-start generator, they normally have to be kept pre-heated 24/7 in cold weather, which can require some serious energy input just to keep the generator warm enough to start on-demand. If the system is not set up properly, it will become a nightmare. So these are all important considerations.
 
Chris Olson
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Location: Northern Wisconsin
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I'm adding some more information to this thread for the benefit of other folks looking at living off-grid, or sizing a generator to an existing off-grid system. And why generators like the Honda EU2000 are basically toys for a full-time off-grid home. This is from our power logging system and it shows the relationship of our generator usage, and how much on each day, for Jan 2014, and six months later in June 2014:



As you can see from the graph, on some days in January the generator produced as much as 28 kWh, and many days over 20 kWh. In June the small bumps in the graph are from days when the inverter overloaded. It calls for power from the generator to assist it, brings the genset online and syncs with it, then uses the genset power to offset some of the loads to reduce the load on the inverter to below it's 6 kW continuous rating. These involve very short run times, but with the generator producing 10% OVER its rated continuous power for up to 30 minutes.

This is the graph for the year to show how generator usage drops off in the summer months and increases quite drastically in the winter:



In January our generator produced 485.115 kWh. To put this into perspective, a Honda EU2000 running at maximum continuous output, would run 323 hours for the month of January alone, or an average of 10.4 hours per day. On the 11th of January when we needed 28 kWh from the generator, a Honda EU2000 would've had to run balls out for 18.7 hours. These little toy generators might work for an RV for a long time, where they run at intermittent loads on auto-throttle. But put one in a real off-grid situation where it has to run balls-out for hours on end, and they are junk in one year.

Few people who have tried living off-grid in the northern climates last more than 5 years at it. A great majority of those don't last two years because they make the mistake of grossly under-sizing their power system, which means huge sacrifices have to be made compared to what they were used to on utility power. Living off-grid is VERY expensive. It costs 3-4x for every kWh what folks on utility power pay. Throwing your money away on equipment that is not designed for off-grid duty only makes it more expensive, and you will be one of the ones that fails at your off-grid attempt inside 2 years. In all my years of off-grid experience, the only thing I have found that cuts it long term is top-of-the-line, no compromise, proven, equipment. And that applies right down to the type of batteries you choose for your system - you can buy the cheap golf cart ones and replace them often, going broke in the process. Or you can spend the money on good ones that last 10+ years on the cycling duty that full-time off-grid life will subject them to.

If you look at our generator usage so far for this year, a Honda EU2000 would have 1,100 hours on it already, at full-rated load, from Jan 1. And this is only for the first 8 months of the year. And 90% of the loads where it is required, it is grossly too small to power them. It can't even power a 240V well pump because any decent sized autotransformer will cause its little inverter to fault on overload when you throw the switch and magnetize the core in the transformer. A 6kVA autotransformer (pretty common on off-grid systems) draws 60-70A on inrush when the core magnetizes. A conventional genset can "soft start" the transformer core. An inverter gen can't.

So for anybody looking at this, please consult a professional who actually has experience with off-grid systems before buying equipment to make sure you're not throwing your money away. These days there's a lot people who have websites and claim "expert" status - few who have the qualifications and experience to back it up.
 
Steven Harris
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Chris... how often do you change the oil in your generator, after how many hours of operation and what oil are you using in the generator, weight and brand please. Which lead acid batteries are you using that will go 10 years on an off grid cycle.

Steve
 
Chris Olson
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Location: Northern Wisconsin
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Steven Harris wrote:Chris... how often do you change the oil in your generator, after how many hours of operation and what oil are you using in the generator, weight and brand please. Which lead acid batteries are you using that will go 10 years on an off grid cycle.


The gas Honda's get changed every 100 hours with Honda HP4, SAE grade 10W-40. The Robin diesel gets changed every 250 hours with Phillips Super HD II SAE grade 30.

We have Rolls-Surrette 5000-series, 48V system, 58 kWh (1,200ah). The Rolls 5000's are rated at 2,100 cycles to 80% DoD, 3,200 cycles to 50% DoD. They are dual container with individually replaceable cells, and have a 10 year warranty. Our system is set up to cycle our batteries once every 7-10 days to 65% DoD (target). They are currently 7 years, 3 months old, they have 727 logged cycles on them. We have battery monitors on each string that log the number of cycles the batteries have for the last 10 years, how long since the last cycle, cycle efficiency, Depth of Discharge, minimum voltage on the cycle, and minimum amperage @ Absorb V on the cycle).

Our power system is a Schneider Electric Conext (formerly Xantrex) XW-series:





 
Steven Harris
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WOW.. that is one incredible wiring job Chris... 14 years of wiring. What have you heard about using a fully synthetic oil in a generator and the number of hours before you change it. I run Mobile 1 in my truck and change the oil every 10,000 or so miles, but its good for 15,000. Heard anything about anyone running 300 hours on full synthetic instead of changing out the regular non-synthetic oil at 100 hours ??

Steve
 
Chris Olson
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Steven Harris wrote:WOW.. that is one incredible wiring job Chris... 14 years of wiring. What have you heard about using a fully synthetic oil in a generator and the number of hours before you change it. I run Mobile 1 in my truck and change the oil every 10,000 or so miles, but its good for 15,000. Heard anything about anyone running 300 hours on full synthetic instead of changing out the regular non-synthetic oil at 100 hours ??


Actually, a lot of that wiring is for generators. I always joke that we have more ways to route power around this place than Con Edison has on their grid system. We have triple redundancy from generators/inverter to loads, which requires considerable transfer switching capability in the event of a lightning strike or system component failure. Remember that we live where temps drop to -40 in the winter time, we get 240" of snowfall here, and there is nobody we can call for help if our system goes down.

One of our generators just auto-started at 10:00 PM due to low battery SOC and extremely poor RE conditions here for the last week. I can monitor our system on my laptop with a web browser, and I just noticed that the system had started it. It's putting out 29.9A @ 238.2V and it's been running for 43 minutes as I snapped this screenshot:



Our present loads in the house alone are almost 1.5 kW.



With an off-grid power system, when it auto-starts a genset the loads are priority, battery charging is secondary. It takes a LOT of power to charge batteries and run your opportunity loads at the same time. Even a small 800ah 24V battery bank requires C/10 (80A) minimum charging current to bulk the bank. At 30V before the bank goes to Absorb V, this equates to 2.7 kW of power input to the inverter @ 90% charging efficiency to bulk a 800ah 24V bank in four hours of generator run time. Typically, off-grid folks take advantage of generator run time for what is called "opportunity loads". In other words we fire up the high draw appliances in the house and get vacuuming of floors done, laundry, etc. This causes loads to increase quite drastically when the generator starts. It's not unusual to see baseline loads at 2-3 kW during the daylight hours if the genset is running. So if you have 2.5 kW baseline loads, plus 2.7 kW on battery charging, that's minimum 6 kW generator required with the genset loaded to 85% rated continuous power. Step that up to a 48V 800ah battery bank and the wattage required to charge battery doubles to 5.4 kW.

I am showing this with a real-time, real life off-grid power system so folks can see what it takes.

Edit:
I had initially responded to this oil debate, but am editing it out. It does not pertain to the context of this thread. The OP wants an auto-start generator for his/her off-grid home, and wonders how reliable they are and how they work. We have used auto-start generators here for years. So attempting to show the benefits and convenience that using one for off-grid power provides. And at the same time trying to cut thru the misinformation that runs rampant on many internet forums and sites concerning what is suitable for an off-grid generator, and what is not.
 
Steven Harris
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Chris... you generator runs a great deal of the time and supplies a significant amount of wattage. The rule use to be is that you size the house to the solar panels, you dont size the solar panels to the house because the cost of panels. In the days of old you'd have to buy the super insulated Sun Frost refrigerators to save on solar power to be off grid and forgot a lot of electrical luxuries.

What do you have in your house that is eating up so much of your power that your generator runs so much.

How many watts of solar panels do you have up and are they on 2 axis trackers

Steve
 
Chris Olson
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Steven Harris wrote:Chris... you generator runs a great deal of the time and supplies a significant amount of wattage. The rule use to be is that you size the house to the solar panels, you dont size the solar panels to the house because the cost of panels. In the days of old you'd have to buy the super insulated Sun Frost refrigerators to save on solar power to be off grid and forgot a lot of electrical luxuries.

What do you have in your house that is eating up so much of your power that your generator runs so much.


We have every electrical luxury you can imagine. While we heat with wood primary, we have ground water heat pump backup for when we're gone in the winter. We have central A/C (1.5 ton), totally electric water heating, electric clothes dryer, electric convection range with induction cooktop, microwave, big screen HDTV, satellite TV and internet, 18 cu ft fridge with ice maker. Plus I have a 1,800 square foot machine shop with 72" bed x 18" swing lathe, Bridgeport vertical mill, CNC plasma table, MIG and stick arc welders, two drill presses, two air compressors, and all the other normal hand and power tools.

This is our home - full time - we are not making any compromises just because we do not have utility power. You think along the terms of a part-time off-grid cabin or seasonal home in the tropical latitudes of central Missouri. Since we have to live with what we have every single day, we go to extremes to make it as "normal" as possible.

We also live in the north where our solar panels are buried under snow and ice 3 months of the year. By January 1 they get so hopeless that we give up on them because it's too much work to keep them dug out, and the days are so short they don't produce any significant energy anyway. For that reason we have 7.5 kW of installed wind power for the winter months. But all wind power can do is carry loads - it can't properly charge a big battery bank because the power output isn't smooth enough. So we have to use generators.

LP gas here is not an option. Can't get it in the winter, and my wife won't allow a gas line coming into the house anyway. So I have designed a 110 gallon electric water heating system (240VAC) that automatically heats our water during periods of peak wind or solar output. Other things like the electric clothes dryer double as aux heating and humidity in the house in the winter time. Our electric range with induction cooktop is 2x the energy efficiency of gas cooking.

Our generators are set up for peak load and prime load. The peaking generator only starts and runs when the inverter overloads. The type of inverter we have has the capability to sync its sine waves on L1 and L2 with the genset, and use the genset in parallel with RE power from the batteries to power heavy loads that neither of them can power by themselves. The inverter is capable of handling the overload long enough to start the peaking generator, warm it up and bring online to reduce the load on the inverter to less than its maximum continuous output. The prime generator (diesel) is used for long periods of high load conditions that don't overload the inverter, but for which RE sources of power can't keep up.

We do not use trackers. They are worthless and don't make it thru the first winter here without being broken. We have 6.75 kW of installed solar capacity in four arrays facing in different directions.

Our off-grid power system cost about $70,000 and there are several very similar to ours up here in full-time off-grid homes. There are also many off-grid cabins and seasonal homes up here, and most of those use cheaper equipment like Outback FX/VFX series inverters with basic 120V power and a 3-4 kW generator. Otherwise all the full-time off-grid homes I know of up here use top-of-line stuff and have 240V split-phase power systems, and none of us do any of the ridiculous stuff you read about on the internet or in Home Power Magazine. We all live pretty darn good up here - but it is not cheap.
 
Steven Harris
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What do you mean your wife won't allow a gas line into the home ?? A gas line is a lot safer than an electrical outlet. There must be nearly 100 million homes in the USA with either propane or natural gas as a source of heating power.

Also, you said,
" Our electric range with induction cooktop is 2x the energy efficiency of gas cooking. "
I'd really like to see your numbers on that and just how you calculated that figure because I say NO WAY is it more efficient on a cost basis than either propane or natural gas. And yes, I do have an induction 'hot plate' which is a pretty awesome device.

Steve
 
Chris Olson
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Steven Harris wrote:
What do you mean your wife won't allow a gas line into the home ?? A gas line is a lot safer than an electrical outlet. There must be nearly 100 million homes in the USA with either propane or natural gas as a source of heating power.


Yeah, try to tell that to all these people:
https://www.google.com/search?q=gas+explosions+in+us

She won't allow it. We had an LP generator once and I used to have to haul the 500 gallon tank on a trailer 55 miles one way to get it filled up for the winter, and hide it out behind a row of pine trees so my wife couldn't see it. And then when it gets to 30 below can't get enough pressure out of it to run a generator anyway. I finally gave up on it and put in a 500 gallon diesel fuel tank instead. The 500 gallon diesel fuel tank stores 69 million BTU vs only 32.8 million BTU for the LP tank, at only 87% of the cost/BTU, and the diesel is 2.1x the thermal efficiency of a high compression LPG engine. It's a no-brainer - diesel power is the only way to go for off-grid. Although we do use a minimal amount of gasoline power in our peaking generator because it has the capability to start at 30 below with minimal pre-heat and accept full load within seconds with no damage to the engine. A diesel can't do that.

We're totally happy with our all-electric home, as we can run our high-draw appliances on solar and wind 9 months of the year, 98% of the time. The other three months of the year we run them on combination RE/diesel power. So our setup is "dual fuel", RE/diesel hybrid. You tie yourself into using LPG for any appliance, and guess what you got? No option to run it on your RE power sources.

Steven Harris wrote:
Also, you said,
" Our electric range with induction cooktop is 2x the energy efficiency of gas cooking. "
I'd really like to see your numbers on that and just how you calculated that figure because I say NO WAY is it more efficient on a cost basis than either propane or natural gas. And yes, I do have an induction 'hot plate' which is a pretty awesome device.


Never said anything about cost efficiency. I did say full-time off-grid living is very expensive. But that has nothing to do with an induction cooktop. When it comes to energy efficiency, it is not even a contest.

According to the U.S. Department of Energy, the efficiency of energy transfer for an induction cooker is 84%, versus 74% for a smooth-top non-induction electrical unit, for an approximate 10% saving in energy for the same amount of heat transfer.[5]

Energy efficiency is the ratio between energy delivered to the food and that consumed by the cooker, considered from the "customer side" of the energy meter. Cooking with gas has an energy efficiency of about 40% at the customer's meter and can be raised only by using very special pots,[6] so the DOE efficiency value will be used.

http://en.wikipedia.org/wiki/Induction_cooking#Efficiency

I don't care if somebody who lives off-grid wants to use LPG all they want. We chose to set up a system where it can be powered from our RE sources most of the time. Of the 14 off-grid homes within a 37 mile radius from here, we are the only ones that have an all-electric home. Everybody else uses LP for one thing or another. Last winter when LP ran out in town and they were trucking it in at $5.80/gallon we were also the only ones that the LP shortage in the Midwest didn't affect. Two of the full-time off-gridders up here came to us last winter and bought several loads of wood from us that they hauled to their places on snowmobiles and sleds because they ran out of LP, couldn't get any, and had no heat in their homes. Both of those homeowners jerked their LP furnaces out this summer and put in central forced-air wood furnaces like we got.

For off-grid energy, it's all about planning and design, where your energy sources come from, and how efficient they are. The only thing LPG has going for it is shelf life. Otherwise it is horrible from an energy efficiency and supply standpoint because it is a low energy-density fuel. When supplies get stretched like they did last winter it is the first fuel that has availability problems. When you live off-grid far away from these various supplies, you can't afford to be hauling fuels with a low energy-density like LPG because you can't store enough BTU to make it thru the winter. What looks good on paper don't necessarily work in the real world.
 
Steven Harris
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Chris,

Otherwise it is horrible from an energy efficiency and supply standpoint because it is a low energy-density fuel. When supplies get stretched like they did last winter it is the first fuel that has availability problems. When you live off-grid far away from these various supplies, you can't afford to be hauling fuels with a low energy-density like LPG because you can't store enough BTU to make it thru the winter. What looks good on paper don't necessarily work in the real world


Don't get me wrong here. I love talking to you and I love that you have taken so much time to give such answers in explicit detail, its helping everyone on the forum...but from a purely technical point of view, propane has a way higher density and heat efficiency than wood does.

1 Lb of dry oak = 8000 BTU's / lb
1 lb of liquid propane under pressure in a tank = 21,660 BTU's / lb
( propane source http://www.engineeringtoolbox.com/propane-d_1423.html)

Oak has a density of : 6.26 lbs per gallon of space.
http://en.wikipedia.org/wiki/Oak
6.26 lbs / gallons of oak x 8000 BTU's / lb = 50,000 BTU's per gallon of wood by volume.
In real life, this will be 25% less, at best, because of the void space in packing it.
Propane is 91,500 BTU/s per gallon of space in a pressured liquid environment.

Propane can be burned with a heating efficiency of up to 98% in a condensing furnace. We had one put in for natural gas in our old house, WOW did the heating bills drops.

No way in hell wood heat is 98% efficient, it'd be below 50%, only Paul's rocket mass heaters would even start to compete with heating at 90% efficient.

So there is no way in hell wood has a higher energy density, not by pound, not by gallon nor by cubic food than propane and certainly not by efficiency.

But do you know when propane is 0% efficient...when you "ain't got none", which is exactly as you said in your previous post about the mid-west running out of propane.
Its easier to think wood has a better energy density because you can haul it in the back of your pick up truck and stack it by hand. Which you can't do with propane. So I can see where many will have the impression that wood has a better energy density, but it does not. In your case for yourself and your neighbors, wood has a better ATTAINABILITY than propane. If you can't get it, it does nothing for you. Wood is more 'under your own control' than propane is.

Ok...that does it for me. As far as I am concerned you are a GOD of off the grid knowledge, especially since you run an energy rich life style for home and for business and you have done it with RE as well as generators. Your photos you put up are nothing but purely masterful of 14 years of experience of off grid living. Also, a force air wood furnace is the only way to go for heating an entire house like most homes are on propane or natural gas, and also allowing you to have an AC evaporator in the unit so you can cool your house.

Steve


 
Chris Olson
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Steven Harris wrote:
So there is no way in hell wood has a higher energy density, not by pound, not by gallon nor by cubic food than propane and certainly not by efficiency.


Steve, you clearly do not understand. We don't burn wood by the pound. We burn it by the cord.

I told the off-gridders around here for the last 5 years that heating their homes with LPG is absolutely ludicrous. We had two warm winters in a row and they all laughed at us. Then last winter we had the coldest and longest winter in over 40 years. Every single one of them was looking for firewood when LP supplies ran out. 1.5 cord of split red oak @ 20% moisture contains more BTU than a 500 gallon tank of LPG. And the wood is right out everybody's back door - we got millions of acres of it up here with mature 120-150 year old trees that have either fallen or need to be harvested to make room for new undergrowth. But it's all about being lazy. They laugh at us because we work thru the middle of summer cutting logs and skidding them out to our landings to season for year, then process last year's logs into 20" lengths, split it and stack it in our woodshed for the upcoming winter. We store 21 face cord in our woodshed for the winter, which is the equivalent in BTU content of five 500 gallon LP tanks filled to 85% capacity:



It takes us about 3 weeks in the late summer/early fall to put it up for the winter. We have a high-efficiency furnace with a catalytic recombustor on it. The only thing that comes out the stack on our house is water vapor, CO2 and a few trace chemicals inherent in wood burning. Our furnace has an EPA efficiency of 83.5%. Our home is 2,500 sq ft and we heat both it and my 1,800 sq ft shop for the winter on that wood supply. We store it all on-site in a relatively small woodshed. There is nobody I know that lives off-grid that has 2,500 gallons of LP storage on site to match what we can store in wood heat.

And this is what I said before about low energy-density fuels and not being able to store enough BTU to make it thru the winter. Last winter we didn't laugh at our neighbors like they laughed at us for the last several years. Instead we helped out the ones we could that did not previously understand the concept of energy storage, capacity, and where that energy comes from. Contrary to your statement I am no "god" of off-grid living. My wife and I just have years of experience with it and we try to pass that on. Few listen because our experience mostly does not agree with the crap you read in Home Power Magazine, or Survival Magazine, or whatever. The reason so many have failed at full-time off-grid living is because in theory there is no difference between theory and practice. In practice there is.

Edit:
Steven Harris wrote:especially since you run an energy rich life style for home and for business and you have done it with RE as well as generators


Also, we do not run an "energy rich" lifestyle. Our home is extremely energy efficient, far surpassing any home that uses LPG or natural gas. We use a lot of electricity, which does not make for "energy rich". To use your analogy, there is no way in hell gas heating can match the efficiency of electric heating. Electrical heating of anything, water included, is almost 100% efficient. Our off-grid power system produces electricity, not natural gas or LPG. Therefore, to make it as energy efficient as possible, use electricity to do things instead of gas.

Our electric appliances still use some fossil fuels in the form of diesel fuel or gasoline. But we also have a quite elaborate power logging system that even logs every last kWh produced by generators, and how many hours they run, accurate to one second. By profession I am a mechanical engineer and I tend to run analysis on things that other folks take for granted. And I have reams of logged data that shows our home is by far more efficient (kWh in vs usable energy out) than any home that uses LPG or natural gas for even one thing, like water heating. The reason is because the energy input required to get your LPG or natural gas out of the ground and to your home is never figured into efficiency figures related to gas. I look at total energy taken from the environment vs what we use in our home when I look at efficiency figures.

But none of this ads up to "energy rich". Granted, we are far from poor and we consciously chose to do what we are doing because we like the location and the solitude - and the fact that it is astronomically expensive (and at this point not even possible) to have utility power run across a sovereign nation owned by Native Americans. There seems to be some confusion in relating use of electricity as an energy source to "energy rich". When it actually the other way around. Most of our electricity is produced by taking nothing from the environment other than what it took to make our solar panels and wind turbine. And the efficiency of each kWh is VERY high for that. Mining frack sand, and drilling and fracking, and pumping, etc., for natural gas and LPG can't even come CLOSE.

So who, really, has the "energy rich" lifestyle?
 
Cj Sloane
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Chris Olson wrote:Our home is 2,500 sq ft and we heat both it and my 1,800 sq ft shop for the winter on that wood supply.


You store 21 cords but how much do you burn? We burn 2 1/2 cords for our 2400 sq ft home - no back up heat but I get cranky if the downstairs is less than 65°. It's R38 on 6 sides and has good passive solar features.
 
Chris Olson
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Cj Verde wrote:You store 21 cords but how much do you burn? We burn 2 1/2 cords for our 2400 sq ft home - no back up heat but I get cranky if the downstairs is less than 65°. It's R38 on 6 sides and has good passive solar features.


It greatly depends on ambient temp. We keep our thermostat set at 68F and last winter when it never got above -20F for 6 weeks and was at -38 to -40 for many nights, we went thru a little over 6 face cord in the house. Most of it gets burned heating my shop, as I keep it at 65F all winter and keep some diesel equipment in there that I use in the woods when I'm logging in the middle of winter. When the snow gets too deep to drive the Dodge Cummins into the woods to pre-heat the log skidder to get it started, I bring it home and keep it in the shop and drive it back out to the woods when I go logging. And I got other stuff coming in and out of there all winter so the big overhead doors get opened a lot during the day. It's not unusual to burn 10-11 face cord in the shop during a winter. You bring a 15 ton log skidder into the shop that's been out in -20F temperatures all day and it takes a LONG time to heat up that mass of steel. It can be at 65F in there and it's about like standing by a giant refrigerator when that cold hunk of steel comes in the shop.

Edit:
Oh, I should mention too that us off-gridders expend a lot of energy keeping certain things warm in the winter that "normal" folks don't have to worry about. Primary is our battery bank. Our power room is not heated but it is on the north end of the house. It provides a dead air space "buffer" between the living area and the outside and we try to keep it above freezing in there for the equipment to prevent condensation. Our battery bank is in an insulated case in the power room and we blow air from the basement into the battery case that is in turn directly vented to the outside. The battery case airflow is 210 CFM 24/7 all winter. That's a huge "leak" directly to the outside but it is necessary for batteries in cold weather, both for venting charging gases and to keep them above 60F.

Since the catalyst on our wood furnace gives off tremendous heat with the stack temp at 600-700F it is normally quite a bit warmer in the basement than the upstairs. So we leave one basement window open all winter, even in extreme cold weather, to provide fresh combustion air for the furnace. We don't like living in a "tight" house. My grandpa always said a drafty house is a healthy house in the winter. Houses that are too tight and don't exchange the air often enough having people living in them that are sick all the time. Neither me nor my wife has even had a common cold in over 12 years. We attribute that to the fact that we don't seal our house up tight in the winter and it exchanges all the air in the house at least twice a day with fresh. Since our heating fuel is basically free, except for the work of putting it up, we have never bothered with heat recovery air exchangers. We do it the old fashioned way with windows.
 
Steven Harris
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both for venting charging gases and to keep them above 60F.


Chris, as an expert on hydrogen, and running a company that publishes the largest amount of books on hydrogen, I can tell you there are NONE, ZERO Charging gasses that you EVER have to worry about no matter what. Any hydrogen generated is leaving the entire building faster than you can run, and its doing it in all directions at the same time. If there is a crack in your house, and you said your house was drafty, the hydrogen is literally leaving the house in a second or two and then diluting itself over the entire globe. Hydrogen in your house literally will make its way over china.

I can literally crack open a 2500 psi cylinder of hydrogen, let it stream out for a few seconds, and then light a bic lighter, and there will be no hydrogen ignition. It leaves that fast, its 1/14th the density of air. It is a concept that is hard for most people to fathom. Hydrogen does not waft around and linger like a fart. I guarantee that the hydrogen I let out at 2500 psi for a few seconds is many many orders of magnitude than what your batteries are making.... and I have no risk even at my level of hydrogen release.

Steve
 
Chris Olson
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Steve,

Steve, the main problem is that we have a quite large battery bank weighing over 2 tons and batteries give off arsine and stibine which are the two toxic gases that make them stink when being absorbed. We have many thousands of dollars worth of equipment in the power room that we do not want corroded, nor do we want metal hydride gases accumulating in the battery case and power room. So we pressure vent (as opposed to vacuum venting) the battery case to the outside, as is standard procedure with any large battery bank.

Also, large batteries enclosed in a case like ours are can very quickly accumulate explosive levels of hydrogen gas within minutes during absorb stage. It only takes a little over 4% by volume to make the mixture explosive. If you do not want to vent your battery case for your off-grid home, or want to charge batteries in free-air in your battery or power room, that's your business. But we prefer to keep our power room clean, free of fumes, cobwebs, moisture, etc..
 
Cj Sloane
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Chris Olson wrote:
Oh, I should mention too that us off-gridders expend a lot of energy keeping certain things warm in the winter that "normal" folks don't have to worry about.


I'm off grid too, but my battery bank is inside in the utility room vented outside.

I can't really think of anything I need to keep warm but I do worry about things normal folks don't. My driveway is a mile so propane has to last October till post-mudseaon (May1).

The guy who designed our house told us as long as we had a dog there'd be plenty or air exchanged from letting the dog in and out.
 
Chris Olson
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Cj Verde wrote:I'm off grid too, but my battery bank is inside in the utility room vented outside.


That's pretty standard in cold climates. In warmer climates in the mid to southern states I've seen many off-grid installations with a separate battery house that's not heated or insulated. Usually just a small wooden shed where the batteries are. If we had it to do over we would not have our power room built onto the house. We would put the equipment and batteries in a separate utility building and bury the necessary ductwork to the building from the house to heat it in the winter. Our XW inverter is mounted on the wall in the power room and on the other side of the wall is the kitchen. The XW's have a big torroid transformer in them that sounds about like a 100kVA three-phase utility transformer and at full load the noise from the transformer is plainly audible in the kitchen thru the wall.

There's probably lots of things off-grid folks would change if they had it to do over.
 
Steven Harris
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THERE IS NO REASON TO KEEP YOUR BATTERIES OUTSIDE. The hydrogen danger issue is a MYTH !!! As I went over carefully in my last posting. You guys might as well be talking about witchcraft in Salem. its ALL hogwash. Hydrogen does NOT waft around like a fart. It leaves a building faster than you can run. As I tell people, treat your batteries better than your dog. If you'd not leave your dog outside in the garage in the winter, or leave him in your attic in the summer, then don't put your batteries there. Your batteries want to be warm and comfortable just like you do. There is a significant and measurable amount of storage LOST for every 10F a lead acid batteries fall in temperature.

Keep them INSIDE, warm, and where you can check on them.

Steve
 
Steven Harris
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Also, large batteries enclosed in a case like ours are can very quickly accumulate explosive levels of hydrogen gas within minutes during absorb stage. It only takes a little over 4% by volume to make the mixture explosive. If you do not want to vent your battery case for your off-grid home, or want to charge batteries in free-air in your battery or power room, that's your business. But we prefer to keep our power room clean, free of fumes, cobwebs, moisture, etc..


yeah.. I KNOW the explosive limits of hydrogen, I have just a FEW books on the subject, plus a hand full of DVDs. What I'm telling you is that me venting a K Cylinder of hydrogen at 2500 psi into a room for let say 10 seconds, will have ZERO combustible or explosive features, and what you are taking about hydrogen developed in a battery is a mouse fart of hydrogen. If you truly understood the physical characteristics of hydrogen you'd realize just how incredible safe it is.

Yes. I've vented K cylinders in rooms for a few seconds (no regulator, right at 2500 psi) , counted to 3 and then flicked a bic lighter just to show how incredibly fast it leaves the entire structure.... and the counting to 3 was just for dramatics, the second I turned off the valve on the cylinder, all of the hydrogen was out of the room.

Steve
 
Chris Olson
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Well, I'd like to sort of point out that our batteries are inside, nice and warm in the winter and nice and cool in the summer. In a room and case designed specifically for them. Our current bank of batteries has been there for over 7 years. You don't want batteries in the living area of the house. They are dangerous. Our battery bank can deliver 1,600 amps to the bus before any breakers would trip if you were to throw a shorting bar across the bus. They weigh over 400lbs each full of electrolyte and it requires a hand truck to move one. They have to be serviced every 3 months, including filling out a log with the SG and at-rest voltage of each cell, and how many cc of water it takes for each cell.

This is why off-grid folks design a room or building specific to batteries, and usually the associated equipment. We are not cave people or some weirdo "preppers". We live normal and that means if I bring 2 tons worth of batteries in the house I got a wife that stands with her hands on her hips and proclaims that I have a choice - I can live with the batteries or live with her, but she's not living with batteries in her house.
 
Chris Olson
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Steven Harris wrote:and what you are taking about hydrogen developed in a battery is a mouse fart of hydrogen.


Steve, I have had two FLA batteries explode in my face over the years and blow the tops right off and totally douse me with battery acid - one starting battery in a semi and one Trojan deep cycle that I was hooking up the cables on. I also had a Craftsman claw hammer accidentally fall into a 1,000A DC bus box once and vaporize in front of my face. I still have burn scars from the hammer explosion. I have basically worked around them pretty much all my adult life and am smart enough to wear safety glasses and gloves when working with them.

Again, I don't care if you want to go blind or are not scared of them. But do NOT urge other folks to do things they shouldn't regarding batteries. A 48V battery bank can lay you out on the floor deader than a doornail if you happen to become the path to battery ground and touch a positive lead. A bank of them is deadly dangerous and you treat them with respect.
 
Chris Olson
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For the benefit of the OP looking at putting in an auto-start genset, here is a couple videos I made on the topic some time back. This first one shows how you can use an auto-start/stop system for a peaking generator to power extreme heavy loads in your home without having to buy more inverters and batteries



This second one is a basic overview of automatic generator starting, more specific to a Schneider Electric XW Power System. But Magnum energy systems are similar. Outback is a different animal because Outback does not make an AGS (Automatic Generator Start) for their systems, and they require the use of an expensive aftermarket Atkinson generator controller. But this shows the basics:

 
Chris Olson
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Steven Harris wrote:Chris, as an expert on hydrogen, and running a company that publishes the largest amount of books on hydrogen, I can tell you there are NONE, ZERO Charging gasses that you EVER have to worry about no matter what.


This has drifted off-topic pretty far for the OP that wanted an auto-start genset. But frankly I can't believe I am reading the above on a public forum. Even a neophyte knows the dangers of batteries. You have obviously never seen an entire string of batteries that blew due to one battery going into thermal runaway. I have. I hope the folks that read this thread have enough common sense to weed out the nonsense.

There are numerous things in a off-grid power system that can kill or injure you, from improper grounding of equipment, to solar arrays running at lethal voltages of 60VDC or above. Wind turbines are also common for off-grid installations and they are more deadly than high voltage solar arrays. Ours runs at 600 volts input to the coupling inverter and it is not even safe to have the high voltage components of it in the power room



I hate this notion that stuff can be cobbled together or corners cut for an off-grid system, some of which compromise the safety of the people that live with the system. I certainly hope any prospective, or even experienced off-gridders that read this come away with a full realization that you do not put batteries anywhere in the living area of your home. And when you work with them, which is a regular part of off-grid life, that you wear and use the proper safety equipment. And realize that while one sitting in the middle of the floor is relatively safe, when you combine a bunch of them into a bank they become very dangerous, and they need to be treated as such.
 
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