Advice needed. Which genset for off grid?

KTMGuy

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Howdy all! New guy here with a question. Im hoping someone has an answer or advice.

Right now Im using the 802A to charge the battery bank on our RV trailer (Arctic Fox) when needed by the 120vac shore line. We have a good solar setup already that I installed last year. When we finally get to our plot of land in Alaska, we will have a cabin built with solar power. Yes, I understand the dark cold winters there. My question is while the 802a is fine for our trailer needs (we use it maybe once a week in bad weather), I dont think it will be a whole cabin type generator, but I could be wrong. We will have a 48v bank of 16 6V batteries (8x8) in series/parallel for 860Ah with a 4000w 48v inverter/charger. We get along fine using our 3000w inverter in the trailer. Winter there is a 3 hour day, so I will need a genset for part of the winter to charge the bank every 2-3 days.

I plan on keeping the 802, but want another for heavier use and have the 802 as a spare when needed. Should I go up to the next size 803? It seems to be a popular model and not too terribly heavy. I plan on having an insulated vented outbuilding for the genset as it does get to -30* or so .

I thank you for your time, thoughts and advice!

Vince
 

nextalcupfan

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Howdy all! New guy here with a question. Im hoping someone has an answer or advice.

Right now Im using the 802A to charge the battery bank on our RV trailer (Arctic Fox) when needed by the 120vac shore line. We have a good solar setup already that I installed last year. When we finally get to our plot of land in Alaska, we will have a cabin built with solar power. Yes, I understand the dark cold winters there. My question is while the 802a is fine for our trailer needs (we use it maybe once a week in bad weather), I dont think it will be a whole cabin type generator, but I could be wrong. We will have a 48v bank of 16 6V batteries (8x8) in series/parallel for 860Ah with a 4000w 48v inverter/charger. We get along fine using our 3000w inverter in the trailer. Winter there is a 3 hour day, so I will need a genset for part of the winter to charge the bank every 2-3 days.

I plan on keeping the 802, but want another for heavier use and have the 802 as a spare when needed. Should I go up to the next size 803? It seems to be a popular model and not too terribly heavy. I plan on having an insulated vented outbuilding for the genset as it does get to -30* or so .

I thank you for your time, thoughts and advice!

Vince
Do you know the maximum charging rate on that inverter/charger? (How many amps it can take at 120v or 240v)

If you're just charging batteries I find it unlikely you'll need more than an 802a.

Keep in mind at the same load the 803a will burn roughly double the fuel of an 802a, if you're charging batteries every 2 days that will add up.

It might be worth looking into getting a preheat kit on your 802a
 

rickf

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If you are living off grid in Alaska that usually means far off the main roads and such. An 802uses roughly 1/2 gallon of fuel per hour of run time. Even running it 12 hours a day is 6 gallons a day, times 4.3 equals 25.8 gallons a month. And if you are far enough off grid so as to need a snowmobile to get there then you would have to plan on fuel storage. I would plan on double that amount for storage to be safe. And to be perfectly honest, if you are depending on this generator for your life........................... Do you really want to put your life, and your family's, on a 40-50 year old genset with very limited parts availability. You might want to do some research on what the people that have been living up there for a few years are doing.
 

Ray70

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If you're looking at -30F an Arctic heater kit is probably a must. If you decide to go with one shoot me a PM, I have one available.
as for the 40-50 year old generator.... WHAT?? they only started making the 802 28 years ago and I'm sure he isn't looking at the OLDEST one he can find!
rofl just poking fun at the 40-50 comment.... but really, there are plenty of 10-15 year old's available out there (y)
 

Jeepadict

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I'm with the other fellas...gotta calc your max load. That will tell you what you need. If it's less than 5kw stay with the 802 because as already mentioned the 803 is gonna burn roughly double the fuel and if you don't give it enough of a load the wetstacking fairy is likely to visit. I seriously doubt your charging needs will even come close to taxing the 802, so you may find yourself buying an electric range just so you can put an occasional load on it. If you ever do actually come up short in generator supply, that just comes to lend on power and circuit management.

Sent from my SM-G970U using Tapatalk
 

Coug

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Not sure about this "double the fuel use" deal. At full load (5kw) the 802 burns 1/2 gallon per hour. At full load the 803A (10kw) burns a gallon. At half load the 803A will burn just slightly more than the 802, simply because it has more mass to keep spinning, but it's certainly not double the amount of fuel for the same load level.


As for whether the 802A is enough for the OP, there are more factors to look into for a cabin compared to an RV.

For starters, the charger or inverter/charger setup for your battery bank will play a role in this. Most inverters with built in chargers can handle a larger input current than they can output, so even though it's 4kw output it might do double that as input. Without knowing the specific make/model I can't tell you that.

Once again, without make/model we don't know if there is a pass through relay as well, meaning you can run directly from the generator when it's running and charge the batteries at the same time, rather than converting power from the input 120/240 to 48V nominal and then inverting it right back up to 120 or 120/240 or whatever the inverter does.

Plus, a cabin is likely to have more/larger appliances than the RV trailer does. I'm going to assume here that you're primarily running either wood or propane as your primary heat source. But how about things like washer and dryer? Hot water tank?

Without knowing more about how you plan to set up the cabin it's hard to give specific, useful advice.
 

Jeepadict

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Coug, I'm tired so hope I get my words right...ya can't examine kw load for fuel usage comparisons. Since we're comparing a nearly identical 2-cylinder to a 4-cylinder...at idle 2 vs 4 of the same size pistons will use the proportionate amount of fuel, same holds true for at rpm...1800 rpm is 1800 rpm so the CFM the engines displace is exactly double, given the average fuel use since the pistons and injectors are approx the same. The only fluctuation would be a surge draw or constant high load draw.

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LEOK

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If I was living off grid, I figure how much to charge my batteries and run the house, then shutdown and run on batteries, and repeat cycle. My gen would be a modern small diesel that will be easy to get parts for like Perkins, same for the gen a modern single phase Mecc-Alte they got parts in Illinois, smart controller like Deep Sea, then build a insulated shed with another room for fuel. 802a for a spare
 

rickf

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could be you need a DC charging generator to keep your batt bank up to level and continue using the inverter.
I think an AC generator is a must in case something happens to the invertor. I am assuming through all of this that you will be using wood for heat?
 

rickf

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If I was living off grid, I figure how much to charge my batteries and run the house, then shutdown and run on batteries, and repeat cycle. My gen would be a modern small diesel that will be easy to get parts for like Perkins, same for the gen a modern single phase Mecc-Alte they got parts in Illinois, smart controller like Deep Sea, then build a insulated shed with another room for fuel. 802a for a spare
This is exactly what I was thinking in my first reply. I was a bit off on the generator dates because for some reason I keep mixing up my 002 with an 802. Old age, what can I tell you. But you have to remember that the military had access to an unlimited parts supply AND they did not have to worry about paying for it, at least not at the user level. If they couldn't get parts they just replaced the genset, simple as that. You are not going to have that option plus, all those parts the military had are not as available as they used to be AND, someone has to pay for them! and getting things to Alaska can be pricey. I like military stuff but I don't think I would put mine and my families life on the line depending on an older military genset. As was said, keep one as a backup but not a main source.
 

justacitizen

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I think an AC generator is a must in case something happens to the invertor. I am assuming through all of this that you will be using wood for heat?
sorry i wasn't clear. i meant to say get a DC charging gen for batt maintenance and keep the 002a for backup emergency and for powering equipment that the inverter can't handle. i would run a fuel comparison first. and definitely ask your neighbors what they do and if you can don't try to be different because neighbors can share spares parts and IT advice. there is safety in numbers
 

KTMGuy

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Do you know the maximum charging rate on that inverter/charger? (How many amps it can take at 120v or 240v)

If you're just charging batteries I find it unlikely you'll need more than an 802a.

Keep in mind at the same load the 803a will burn roughly double the fuel of an 802a, if you're charging batteries every 2 days that will add up.

It might be worth looking into getting a preheat kit on your 802a
Yes! I'll be using 2- 48v 30amp chargers in parallel. Sorry, I should have put more specs out front, but we had friends show up with some good beer so the post was rushed a bit. Free beer beats forum - I hope you understand.

And yes, it (the genset) will only be used to charge the battery bank when needed. Im going for "worse case" and will plan for it as well as possible. I would rather have it and not need it and so on. Having to charge once every 2-3 days is the worst case I can imagine. Even on a cloudy snowy day there will be some charging from the panels. My array will be in the neighborhood of 3000w and the bank will not be going below 50% if possible.

Diesel fuel is not a problem as the tank on my truck is 40 gallons and theres an aux tank of 50 gallons in the bed should I need more. Jerry cans are cheap too. At full charging, my 802 drinks around 1/2 gallon an hour (guesstimate) and the RV bank is charged in about 2 hours but thats a lithium battery bank at 12v/400ah total down to 20-30%. The lithiums can charge much faster than lead acid.

Ouch! $2k for a preheater? It would be cheaper and better to get another surplus genset with the preheater already on it, but if I have to then I have to.

Vince
 

KTMGuy

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If you are living off grid in Alaska that usually means far off the main roads and such. An 802uses roughly 1/2 gallon of fuel per hour of run time. Even running it 12 hours a day is 6 gallons a day, times 4.3 equals 25.8 gallons a month. And if you are far enough off grid so as to need a snowmobile to get there then you would have to plan on fuel storage. I would plan on double that amount for storage to be safe. And to be perfectly honest, if you are depending on this generator for your life........................... Do you really want to put your life, and your family's, on a 40-50 year old genset with very limited parts availability. You might want to do some research on what the people that have been living up there for a few years are doing.
Well, we'll be between Willow and Wasilla, so its a 20 minute drive either way to town, but I get your point and its a valid one I assure you.

I will have a minimum of two 50 gallon drums stored in the garage. My truck carries 90 gallons on its own.

No, Im not betting my or my families lives on anything. Thats why Im here - to get ideas and advice. Im a great believer in being prepared for just about anything and Im paranoid to boot. I know its not possible to be 100% prepared for 100% of everything, but I plan on giving it a good try! Its really all about attitude. I like to think that being a grunt for 20 years has taught me something, but if not, then the Army needs to get a refund.

I have done research on off grid living in Alaska. I have several friends that live off grid there and while I listen to their advice, I will still do things my way because everybody is different and everybody has different wants and needs. My wife and I love the simple life, but still want our luxuries like heat, running water, a toilet, a hot shower, a microwave, etc. We're simple - not morons. :)

Vince
 

KTMGuy

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If you're looking at -30F an Arctic heater kit is probably a must. If you decide to go with one shoot me a PM, I have one available.
as for the 40-50 year old generator.... WHAT?? they only started making the 802 28 years ago and I'm sure he isn't looking at the OLDEST one he can find!
rofl just poking fun at the 40-50 comment.... but really, there are plenty of 10-15 year old's available out there (y)
Its looking that way and I'll keep you in mind - I tend to overthink things, but I thought it was a fairly simple problem!

Vince
 

KTMGuy

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Indiana
I'm with the other fellas...gotta calc your max load. That will tell you what you need. If it's less than 5kw stay with the 802 because as already mentioned the 803 is gonna burn roughly double the fuel and if you don't give it enough of a load the wetstacking fairy is likely to visit. I seriously doubt your charging needs will even come close to taxing the 802, so you may find yourself buying an electric range just so you can put an occasional load on it. If you ever do actually come up short in generator supply, that just comes to lend on power and circuit management.

Sent from my SM-G970U using Tapatalk
Yep, your right but it was free beer last night, so one must make allowances. As of now the total power usage is :

Splendide washer/dryer - 1300W
Led lighting - less than 200W total
40" LED tv - 36W
Ceiling fans (2) 100w total
6qt instant pot - 1000w
Gas stove /gas fridge - none
Coffee maker - on stove so none also.
Well pump - depends, but 5000W startup and 2500W running is just ball park. Wont know till we drill first.
Phones/tablets/flashlights and what have you - add another 30W or so.
Heat will be provided by a wood/coal stove.
Hot water will be an instant water heater using gas.
Can change day to day as the wife thinks about it.

Vince
 
Last edited:

KTMGuy

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Not sure about this "double the fuel use" deal. At full load (5kw) the 802 burns 1/2 gallon per hour. At full load the 803A (10kw) burns a gallon. At half load the 803A will burn just slightly more than the 802, simply because it has more mass to keep spinning, but it's certainly not double the amount of fuel for the same load level.


As for whether the 802A is enough for the OP, there are more factors to look into for a cabin compared to an RV.

For starters, the charger or inverter/charger setup for your battery bank will play a role in this. Most inverters with built in chargers can handle a larger input current than they can output, so even though it's 4kw output it might do double that as input. Without knowing the specific make/model I can't tell you that.

Once again, without make/model we don't know if there is a pass through relay as well, meaning you can run directly from the generator when it's running and charge the batteries at the same time, rather than converting power from the input 120/240 to 48V nominal and then inverting it right back up to 120 or 120/240 or whatever the inverter does.

Plus, a cabin is likely to have more/larger appliances than the RV trailer does. I'm going to assume here that you're primarily running either wood or propane as your primary heat source. But how about things like washer and dryer? Hot water tank?

Without knowing more about how you plan to set up the cabin it's hard to give specific, useful advice.
Exactly - the inverter can surge to 8000w. My plan as it is, is to have separate charging methods - charge from solar panels and a separate charge by genset as needed. I've learned to never rely on just one thing.

See my post above for the cabins power usage. I forgot to add the on demand instant hot water heater for the cabin - it'll be gas, not electricity.

Vince
 

rickf

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I lived off grid for two years in Maine, myself and my girlfriend. This was in the 70's so no solar, no generator, no electricity. Nearest town was 50 some miles but we only went there every 6 months or so and definitely not in winter.
but still want our luxuries like heat, running water, a toilet, a hot shower, a microwave, etc. We're simple - not morons. :)
With all of that I would like to think I am not a moron, we lived quite comfortably with all of the basics needed. We had a hand operated water pump, water heated by the wood stove and cooking done by the same wood stove. Light provided by candles and oil lanterns. And of coarse, an outhouse, A two seater at that!!! How's that for luxury? Transport if needed was an old Skidoo snowmobile but sleds of that era were far from what could be called dependable so it was basically emergency only and to get a large deer out of the woods.
But anyway, history lesson out of the way. I have never lived in Alaska and have never been there in the winter. I have friends there and I know it can get damn cold. I also know that the sun angle is worthless for solar so you might want to do some research on just how much power you will actually get from those panels in the Alaskan winter. Even on a full sun day with the low angle of the sun you will get little energy from them. I am far from an expert so do your own research. I would hate to see you jump into this and find out that you made an expensive mistake. Everyone wants to do it "their own way" but there are some ways that just will not work in some places.
 

KTMGuy

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Location
Indiana
If I was living off grid, I figure how much to charge my batteries and run the house, then shutdown and run on batteries, and repeat cycle. My gen would be a modern small diesel that will be easy to get parts for like Perkins, same for the gen a modern single phase Mecc-Alte they got parts in Illinois, smart controller like Deep Sea, then build a insulated shed with another room for fuel. 802a for a spare
Thank you, LEOK. Thats why Im here to get advice and ideas. What a wonderful group here!

Vince
 

KTMGuy

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Indiana
I lived off grid for two years in Maine, myself and my girlfriend. This was in the 70's so no solar, no generator, no electricity. Nearest town was 50 some miles but we only went there every 6 months or so and definitely not in winter.
but still want our luxuries like heat, running water, a toilet, a hot shower, a microwave, etc. We're simple - not morons. :)
With all of that I would like to think I am not a moron, we lived quite comfortably with all of the basics needed. We had a hand operated water pump, water heated by the wood stove and cooking done by the same wood stove. Light provided by candles and oil lanterns. And of coarse, an outhouse, A two seater at that!!! How's that for luxury? Transport if needed was an old Skidoo snowmobile but sleds of that era were far from what could be called dependable so it was basically emergency only and to get a large deer out of the woods.
But anyway, history lesson out of the way. I have never lived in Alaska and have never been there in the winter. I have friends there and I know it can get damn cold. I also know that the sun angle is worthless for solar so you might want to do some research on just how much power you will actually get from those panels in the Alaskan winter. Even on a full sun day with the low angle of the sun you will get little energy from them. I am far from an expert so do your own research. I would hate to see you jump into this and find out that you made an expensive mistake. Everyone wants to do it "their own way" but there are some ways that just will not work in some places.
Ha! Forgive me for my poor choice of words. I watch too many episodes of the 3 Stooges.

Theres "needs" and "wants" in every aspect of life. Im old enough to want the heat, water, stove, fridge, tv, phones and entertainment. I have an awesome motorcycle that goes very fast and can spray dirt and rocks at people 100 ft away easily. I consider it a want and a need.

The sun angle is pretty near the horizon (21 degrees) in winter with an average of 3 hours of sunlight. The panels will only get an hour or 2 of sun if there are no obstructions in the way - like trees, of which there are many, so we will need a generator to charge the bank every 2-4 days depending. Solar panels have come a long way from even 5 years ago - very high efficiency, but they still need sun time. We're still debating on a ground mount or a tracking array on a pole.

We got 7 acres for $30k, so land is still cheap in places. The 20x24 modern log cabin will cost us $43k built and the solar power will be another $10k or so as we will install it ourselves. Im retired and have lots of time on my hands. Lots of people in Alaska and other parts of the world are "off grid" and do just fine in winter. If you want to see winter, then visit Norway - Alaska is the beach compared to that place. I've been to the sandbox several times and instantly thought how nice Alaska is in the winter.

Vince
 
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