12VDC and system (battery and Solar) needed for wood stove exhaust extraction blower

[ianganderton]

, the other thing with cold air is that it is very moist so then you get creosote buildup.
.

worth noting that cold air holds a lot less moisture than warm air so is therefore drier

Heating cold air is a great way to prevent condensation

 

[Rednecktek]

RedNeckTek: Excellent 'letter' I will reply (later to your comments and questions). I also agree that the 200CFM may be too much... but I figure I can not cut a 'board' and make it longer so IF I go big and then can use a dimmer switch control that might assure my ability to control to minimum need of CFM... (that is I can not lose) If I do the dimmer control for speed control will I save voltage? My ability to understand all the electrical is where I m limited...!!

The only thing to be aware of is that a DC motor rheostat and a dimmer for an AC light are two different things. If you do the test run on the AC fans that you have now you'll be able to guesstimate the amperage draw of the adjustable DC fans, roughly. The only way to get more accurate numbers is to actually build the system with the DC parts and check via shunt or power meter what you're actually drawing.

In short, yes. Throw some rheostats on those to control the speed needed and you'll save power draw prolonging the feed time of the batteries. Building for worst case scenario can only benefit you now that you've got a rough idea of what that would be.

 

[Get1949]

The only thing to be aware of is that a DC motor rheostat and a dimmer for an AC light are two different things. If you do the test run on the AC fans that you have now you'll be able to guesstimate the amperage draw of the adjustable DC fans, roughly. The only way to get more accurate numbers is to actually build the system with the DC parts and check via shunt or power meter what you're actually drawing.

In short, yes. Throw some rheostats on those to control the speed needed and you'll save power draw prolonging the feed time of the batteries. Building for worst case scenario can only benefit you now that you've got a rough idea of what that would be.

EXCELLENT...RedNeckTek See your message here with my comments in "(((" yada yada yada ")))" Triple brackets. THANKS!!

So, it's just a math problem. You'll need 5Ah of battery per hour of burning so worst-case scenario would be 24hr X 5Ah = 120Ah/Day @ 12v = 1440wh of power

That's easy, if you go LiFe battery you'll need 144Ah or 1728Wh of power per day which means a 200Ah battery (or 2x 100Ah in parallel) which I recommend because of the sheer number of batteries required for feeding that system for a few days. Optimally 3 or 4 of the 200Ah batteries just for longevity. (((LiFePo I surfed that they are pricey, huh?!)))

You COULD use FLA or AGM batteries, but 1: they're only 50% DOD so you'll need twice as many batteries which is heavy and takes up a lot of space and 2: they're not usually available over about 100Ah which means twice as many batteries again. In short, you'll need 4 AGM's to replace a single 200Ah LiFe battery.

Panel wise, and I don't know how much sun you have available in winter, I'd say get a 60a MPPT controller and 800w of panel figured out either large modern panels or lots of smaller panels on a ground mount or something. Physics come into play here more than anything else. At 60a and a 12v system you'll only be able to collect a max of 720w and it'll take at least 3 hours of good sun to recover what your fans have used up. Fortunately, there's nothing wrong with using multiple controllers and panel arrays in parallel to charge faster, you just run into physics and finances issues at that point. (((YUP, Dollars and Donuts…bunches! Hmmmmmmmmmmmmmmmm?!?!?)))

As to HOW to get the power out from there, an automotive bus block would be the best way to go. A 5a fuse to feed each fan, a switch to turn them on and off, and it will give you the ability to pipe out to other 12v devices, like USB chargers and lights and such. You might not get very good signal on the phone if SHTF but emergency alerts will still be happening and it's also a handy flashlight. Lights are also important as feeding a fire gets really hard if you're cutting kindling in pitch black darkness. (((Good point I do have enough batteries to put a dent in failure to survive…but your point is well accepted and agreeable)))

Connecting up the batteries I would recommend using a bus block and connecting each battery individually. That way if you need to pull a battery to charge elsewhere you can disconnect and pull a battery without disturbing the other ones and the system would continue to run everything.

OK, does that make sense to anyone else?

Now, there are a couple of things that can be done to help make the process a bit more efficient but not much. The first thought in my head was "Do you really need fans that powerful?" (((I was wondering about computer fans but have not tried them—perhaps I should. I also have these real cheap 4inch fans that came with a little 5 square solar panel and hooked them to a bigger panel…I thought they would fly south they ran so fast…ha ha ha. I could duct them and use them in place of the pictures large AC fan (!?!?!).))) 200CFM is a LOT of airflow and that air has to come from somewhere, just as likely to be your fire box which means you'll be going through wood like crazy (((Yes that would be true except that if you look to the pictures and the #2 that ‘joint’ can be opened to allow more outside air in which would cause less ‘pull’ on the exhaust gases from the smaller stove pipe and stove (I believe, anyway) Also it is possible that I would ONLY have the fans on when loading wood because the small amount of pipe from the stove exit to the end of the hot pipe is not that long (3 vertical ft & 6 horizontal ft) and without the fan operating (at “the barn”) the stove worked quite well all by itself!))). Have you looked at Marine ductwork fans? (((the two DC fans I have are marine bilge blowers—they are sort-ta cool…even cute ha ha ha… picture to follow))) Would a 100CFM fan still do the job? The smallest fan you actually need (((I would like to try smaller fans—perhaps I’ll experiment))), and since you're using 2 do they BOTH have to be 200CFM? Can your system work with, say, a 100CFM and a 50CFM? (The point being that any air you suck through the firebox that is beyond what smoke is produced is just blowing excess heat outside AND drawing extra amperage off your batteries. Might be something to look into. (((You are absolutely CORRECT…This is sort-ta a ‘fun’ experiment which I also hope will never be needed…Biden’s antics and demented and delusional behavior is making me itchy – I’m 23 years military!!)))

Since you did your tests with 120v fans, I'd say grab a couple cheap dimmer switches from the hardware store, wire them into the fans, and re-run your test at the barn. Turn the fan speed down until the system isn't quite working right and that'll give you a rough idea of what kind of CFM you'll need. Were you able to turn the fans down about half? Maybe 100CFM's then. Did you get it down 3/4? 50CFM there. Started freaking out right out the gate? Yup, 200's needed. You might find you'll need significantly smaller fans than your 200CFM's you're planning now and the test will only cost you about $20 in parts and some time. If it means your draw drops by half, that's half the battery capacity you'll need for the same runtime. (((Aaaaah! EXCELLENT LOGIC!! YUP, why didn’t I think of that!!?? Perfect logic perhaps I was breathing in too much of the stove smoke. Ha ha ha ha… I’m off to try again and with smaller fans. THANKS. Ultimately, with more tests and small CFM I’ll not need bunches of batteries and such thereby saving me money in the long-run)))

Just my thoughts. I like what you came up with, I just think it needs a little fine tuning for efficiency and optimal fuel burn time

 

[Get1949]

FOR RedNeckTek... 12 VDC 2.5 amp marine bilge fans...

 

[Get1949]

Bilge fans: The fourth picture is best for orientation of the hot stove pipe (using one fan). The stove would be to the right, the small stainless steel pipe is horizontal, the blower fan is at the bottom blowing air UP and out the large "Y" pipe end at the left, the air going around the small hot small pipe END will draw the hot gases out to the atmosphere, the pipe end at the right top where the hot pipe enters the "Y" (leg) would be packed around its edges with stove door fiberglass ribbon/rope to stop the fan air from going out that way--forcing it out the large end. If I use TWO fans than as seen in the first picture I would need to cut into the 'crotch' of the "Y" to insert the small hot stove pipe. ENJOY...

 

[Isaac-1]

There are a lot of cheaper ways to do this, but just to answer your question, you will need about 120 amp hours worth of batteries to run that blower for 24 hours, to recharge that battery with solar, assuming typical my North America average hours of winter daylight and a mostly sunny day you will need about 500 watts worth of solar panels which will take up an area about the size of a 4 x 8 sheet of plywood, if you have cloudy weather you would need much more.

Here is my proposed, rigged alternative:

5 gallon propane tank ($50 from a tank exchange rack)

RV propane furnace with 12V blower ducting the exhaust outside here is a 25,000 btu Suburban model for $299 dent and ding on ebay https://www.ebay.com/itm/393627572859 The blower on this model draws only about 7 amps and that is only while running.

Rough figures a 25,000 btu rv furnace will burn 1/4 gallon of propane per hour, so running flat out full tilt you would need a 5 gallon tank every day. Reality depending on the temperature you want to maintain you might run 25-50% of the time, just a guess there as North Dakota is likely different than North Texas, though North Dakota condo would likely be better insulated.

Add in a 100 AH LiFePo4 Lithium deep cycle battery (as little as $299 on amazon or ebay) and charge it from the alternator in your Jeep, LiFePo4 can charge at up to 1C meaning 100 amps per hour, though you might burn out your alternator at that speed at idle, you may need a way to slow the charge rate to say 50 amps per hour, running the jeep for 2 hours per day would fully recharge the battery, alternatively buy a cheap $350 inverter generator (such as https://www.harborfreight.com/gener...enerator-with-co-secure-technology-57063.html when on sale) and a 50 amp lithium charger for $100 and recharge it that way.

p.s. the thing that worries me about your setup is no safeties, the fan dies, and you may die, RV furnaces have sail switches and propane disconnect solenoids so if the fan fails it senses lack of air flow and kills the propane supply. they also have flame sensors which tries to relight the flame, and if that fails it cuts off the propane solenoid.

 

[Rednecktek]

OK, a couple initial thoughts now that I look at the pipe the right direction:

You COULD use old PC fans but there are 3 inherent problems with that idea:
1: Getting a square fan to connect up to a round hole requires some specialty parts not seen in stores since PC's went from beige to black and they don't like the heat that a stove pipe is going to put out.
2: Even the best quality fans will eat up their bearings in the smoke in nothing flat.
3: A 4" (120mm standard) case fan doesn't move that much air in comparison to what a bilge blower will. I have the 270CFM bigger brother of those for my cabin BTW.

It would be interesting to try though just for giggles.

Stick with the bilge fans and a rheostat to slow them down. At least then you'll be able to turn them up or down as needed for optimum flow. That's assuming that your A/C dimmer switch test doesn't tell you to get different fans all together.

Yes, the LiFe batteries are expensive (and I'm a total AGM/FLA fanboi), but at only 50lb they're a LOT easier to move around and stack than comparable AGM's or FLA's. A good quality 100Ah AGM is going to cost you easily $350, and since you'll need 4 of them to get the same usable amp hours it's significantly cheaper to buy a $700 LiFe instead. This is another one of those obnoxious "Physics" issues. Sure, a dozen 200Ah sounds great, until you're sleeping in the kitchen because you don't have space for a bed any more. Plus, it's not usually a problem to start with a battery or two and scale up from there, especially if you've got them all connected to a bus block. You just bolt another one on and walk away.

The only way to really shave off this cost is by using the cheap "Marine" deep cycles at Wally World for $100ea, so only $400 for 200Ah of runtime. Granted these batteries are about the same weight but you'll have 4 of them to stick somewhere at a time and there are concerns about hydrogen gas and a fireplace to be considered too.

And yeah, I make weird stuff because I'm bored too, you should look up my heater doodle thread in the Off-Grid section.

 

[Get1949]

There are a lot of cheaper ways to do this, but just to answer your question, you will need about 120 amp hours worth of batteries to run that blower for 24 hours, to recharge that battery with solar, assuming typical my North America average hours of winter daylight and a mostly sunny day you will need about 500 watts worth of solar panels which will take up an area about the size of a 4 x 8 sheet of plywood, if you have cloudy weather you would need much more.

Here is my proposed, rigged alternative:

5 gallon propane tank ($50 from a tank exchange rack)

RV propane furnace with 12V blower ducting the exhaust outside here is a 25,000 btu Suburban model for $299 dent and ding on ebay https://www.ebay.com/itm/393627572859 The blower on this model draws only about 7 amps and that is only while running.

Rough figures a 25,000 btu rv furnace will burn 1/4 gallon of propane per hour, so running flat out full tilt you would need a 5 gallon tank every day. Reality depending on the temperature you want to maintain you might run 25-50% of the time, just a guess there as North Dakota is likely different than North Texas, though North Dakota condo would likely be better insulated.

Add in a 100 AH LiFePo4 Lithium deep cycle battery (as little as $299 on amazon or ebay) and charge it from the alternator in your Jeep, LiFePo4 can charge at up to 1C meaning 100 amps per hour, though you might burn out your alternator at that speed at idle, you may need a way to slow the charge rate to say 50 amps per hour, running the jeep for 2 hours per day would fully recharge the battery, alternatively buy a cheap $350 inverter generator (such as https://www.harborfreight.com/gener...enerator-with-co-secure-technology-57063.html when on sale) and a 50 amp lithium charger for $100 and recharge it that way.

p.s. the thing that worries me about your setup is no safeties, the fan dies, and you may die, RV furnaces have sail switches and propane disconnect solenoids so if the fan fails it senses lack of air flow and kills the propane supply. they also have flame sensors which tries to relight the flame, and if that fails it cuts off the propane solenoid.

Thanks, Isaac-1, I have one question for you. When the power goes out and I burn up the one 5 gallon propane tank how am I going to purchase any more of them or get the empty filled...when there is no power? I can not store a bunch of 5 gallon propane tanks in a condo...while the status of 'society' is good and the power is normal. I have a large free source of (cured) oak.

 

[Rednecktek]

Hmmmmmmm, what if I put the solar panels on the roof of my Jeep (orientating it to get the best sun) with the cables going into the interior of the jeep to the controller and battery. Once the battery is charged then I bring it inside the Condo. I suppose I could end up blowing up the Jeep then with hydrogen gas,

And that's one of the reasons why I pointed you to the LiFe's. Slinging a 60lb battery to the car to charge is a LOT easier than slinging a 95lb battery, then another 95lb battery, then another, then the fourth. Stairs will get old Real Quick!

Having a charging station in the jeep isn't a horrible idea, especially if you can build up 2 charging stations, 1 in the condo with panels on the porch or something and a secondary charger based out of the jeep. In a pinch you can always pack up and move with the jeep and still have charging capabilities.

Say it with me now: 2 is 1, and 1 is None!

Plus, unless you have the world's most airtight jeep (Ha!) you'll probably get plenty of ventilation out there, plus just opening and closing the door will take care of any possible gas buildup.

Plus, building 2 systems is twice the fun!

Check out Will's super simple 400w system for your jeep setup, that should be just about the right fit.

 

[Isaac-1]

Thanks, Isaac-1, I have one question for you. When the power goes out and I burn up the one 5 gallon propane tank how am I going to purchase any more of them or get the empty filled...when there is no power? I can not store a bunch of 5 gallon propane tanks in a condo...while the status of 'society' is good and the power is normal. I have a large free source of (cured) oak.

Well hopefully the power will come back on in a day or two, and hopefully you can ration the propane until then, or drive to somewhere to resupply. Either way if we are talking about society collapsing, no running water, no food in the grocery stores, etc. Then chances are living anywhere that there are condos is probably not the place where you would want to stay long term.

 

[Get1949]

Well hopefully the power will come back on in a day or two, and hopefully you can ration the propane until then, or drive to somewhere to resupply. Either way if we are talking about society collapsing, no running water, no food in the grocery stores, etc. Then chances are living anywhere that there are condos is probably not the place where you would want to stay long term.

Yaa, Hard to guess just what might occur an plan for them all--very difficult to be a prepper in a condo. So at best all I can do is do my best thinking and such. I do have plenty of supplies (food and such) to nearly get me through the winter. I can even cook using marine alcohol fuel. But I'm surprised by the hydrogen comments when it comes to charging batteries--can't have hydrogen 'floating' around if I'm planning on heating up a can of soup on an alcohol burner...or even have a wood stove. BOOM! NoOOooo...BOOMS!

 

[Bluedog225]

This is a bad idea. There are many safety violations and you may kill other people. You not wanting to relocate to a warming location does not make this an all bets are off survival situation. You have alternatives.

 

[Supervstech]

And that's one of the reasons why I pointed you to the LiFe's. Slinging a 60lb battery to the car to charge is a LOT easier than slinging a 95lb battery, then another 95lb battery, then another, then the fourth. Stairs will get old Real Quick!

Having a charging station in the jeep isn't a horrible idea, especially if you can build up 2 charging stations, 1 in the condo with panels on the porch or something and a secondary charger based out of the jeep. In a pinch you can always pack up and move with the jeep and still have charging capabilities.

Say it with me now: 2 is 1, and 1 is None!

Plus, unless you have the world's most airtight jeep (Ha!) you'll probably get plenty of ventilation out there, plus just opening and closing the door will take care of any possible gas buildup.

Plus, building 2 systems is twice the fun!

Check out Will's super simple 400w system for your jeep setup, that should be just about the right fit.

Heh…

My condo has a back patio, I lean a 375W panel against the building… charging a few lithium batteries in my dining room… and my suburban out front has 3 100 W panels on the roof charging it and several various batteries, and my 3 solar generators…

 

[chopper]

Have you looked into thermo electric fans on amazon and info at Thor Labs or possibly using a peltier cooling module in reverse. If this would work you would only need a small battery to power fans until therm devices begin producing. Might use small battery system for fans and charge with thermo couplers.
Just a thought.

 

[A.Justice]

My 2¢ would be to:

1) Use smaller fans. Small, contained stove fires won't need anywhere near 200cfm. IIRC, they use something like 10-40cfm. Any more air and you're either stoking the fire which is wasting fuel, or you're blowing / sucking some of your heat back out of the stove pipe.

2) Look into how they used to install wood stoves into mobile homes, the way that they're installed seems like what you're trying to do. Some of them use a cold air intake which act like an air isolation system. Instead of air for the fire being pulled from inside of your dwelling, they have a pipe that pulls air in from outside, so it isolates the air supply in your home from the stove. For the most part, they've stopped installing stoves like that because of reverse drafting problems, but if you were able to keep your flu under negative pressure I don't think you would have the same sorts of issues.

 

[Brett V]

Do some reading on Co2 the silent killer. What you’re proposing, Is a tragic accident waiting to happen.

 

[Just John]

I believe I have a unique problem to solve. I live in an all-electric condo complex on a second floor that has a small balcony. Should I/(WE) lose electricity in the depths of a cold January/February then about 100 people will have to leave their condos or freeze — NOT ME! (there are three separate buildings in the complex each with about 30+ people—families)

Over the past 6 months I have been experimenting with a stainless-steel camp wood stove (sort-ta meant for outdoors) with a way to extract the exhaust fumes from the stove (and seeing as how I have a porch above me and one below me…this presents a problem!) by running a chimney (type) exhaust pipe up over the roof top for draft is totally out of the question (in fact, it is laughable).

Now, using this stove when conditions are normal (electricity there) would be illegal (via the condo rules…and rightfully so). But when the SHTF… the rules will go out the window as residing here would then become a survival issue.

So, I made up as 4” to 6” diameter stove pipe system that goes out my window with the exhaust pipe going through the (opened) window and onto the porch via specials heat-proof seals and brackets and sheet metal barrier so as to not cause a fire issue (as the hot pipe passes through the window) — this was all tested three times without issue at a friend’s barn. Then I put a 12V - 2.5Amp 200CFM DC ducted (4-inch diameter) fan that blows into a 6” diameter pipe in which the 4-inch exhaust pipe is “Y” cut into the 6-inch duct. With the fan on it blows cold air (the fan is outside with the pipe arrangement) so fast past the exit end of the hot exhaust pipe that it causes a venturi effect that sucks the exhaust out of the exit pipe/end of the 6” dia. pipe.

When I open the door of the stove (WHEN THIS FAN IS ON) I can easily feed the stove wood (I have a source of free oak) without any concern of back draft and smoke entering the condo! It works so well that I should patent it! (Hint Hint for you!!). Now here is the catch…

All the testing done so far has been with a 110/115 ducted fan with a CFM that is a bit higher than the 200 CFM DC fan. So, although I am sure it will work with DC voltage, I have not been able to test that yet but with… TWO 200 cfm ducted DC fans in a special pipe (another “Y” connector) I now have air flow CFM above the tested 115 AC volt fan CFM. With a dimmer switch I should be able to adjust for the best CFM and save voltage that would come from a battery system…(?)

SOoooo, I need to have a source of DC voltage that will run these: TWO – 12 Volt DC – 2.5 Amp ducted fans and looking at the specs off the box it mentions: Output-open flow data: @13.6 volts: 230CFM, @12.0 volts 200 CFM, @12 Volts DC… 2.5 Amps. Fuse size 5 amps.

My ability to get good solar is limited but I thought I might be able to put the solar panels on the roof of my jeep with the battery charging apparatus inside and orientate the jeep to get the best direct sun (charge the battery then bring it inside to run stove fans)…is this a good idea? Other than that, I can hang solar panels off my porch that has an area of useable and easily accessible dimension of 10 X 10 feet. It gets some direct sun in the morning (8ish AM to 11AM) then indirect sharp angle light until 1PM then in shadow of the building with only indirect light as the sun goes behind my building (my porch is in the front).

Can you set me up with what I need? Will has some complete systems on his web or his youtube channel that I can go see and purchase. I can send some pictures if this helps.

Thanks

Gordon

Get one or two 12v batteries and a solar charge controller with a couple of panels. Will has reviewed several batteries recently that would work just fine.

I have experienced a similar situation where it suddenly dropped below zero Fahrenheit in the deep south. I had a kerosene heater that kept everything warm, but don't forget, your neighbors won't have a source of heat. Pipes will freeze.

 

[Get1949]

My 2¢ would be to:

1) Use smaller fans. Small, contained stove fires won't need anywhere near 200cfm. IIRC, they use something like 10-40cfm. Any more air and you're either stoking the fire which is wasting fuel, or you're blowing / sucking some of your heat back out of the stove pipe.

2) Look into how they used to install wood stoves into mobile homes, the way that they're installed seems like what you're trying to do. Some of them use a cold air intake which act like an air isolation system. Instead of air for the fire being pulled from inside of your dwelling, they have a pipe that pulls air in from outside, so it isolates the air supply in your home from the stove. For the most part, they've stopped installing stoves like that because of reverse drafting problems, but if you were able to keep your flu under negative pressure I don't think you would have the same sorts of issues.

A. Justice: Thanks, you are the second person to hint at smaller CFM. I will do this...been surfing the web. (will do some more testing at "the barn") Had another thought that if I could get lower CFM to work and of course it would be a DC Volt fan, then perhaps I could get a couple of batteries that would give me enough operational time to get me though the initial issues of no power for a couple weeks (after that amount of time the zone in the power outage will be in a state of national attention)...?!!? I'll probably only need the fan(s) on when opening the door to feed it wood...other than that the stove seems to draft OK (better) with a very short exhaust pipe. And with some thought I can get it down to maybe 2-3 vertical feet inside (brings it to window height) then 3-4 feet horizontal to the window (and out) then a 45 degree up and out to the atmosphere and too inside a bigger 6" dia fitting...all of this can be wrapped in insulation...if needed. Charging batteries is now a concern for hydrogen...I have no place to charge the batteries except in what would be left of the living space. Also, I have already considered a way to allow some fresh outside air to be the air that the stove will use to burn the wood... sort-ta. No sense using up... the warm air inside... to burn the wood... a simple dryer duct flex pipe will do....

 

[Get1949]

Get one or two 12v batteries and a solar charge controller with a couple of panels. Will has reviewed several batteries recently that would work just fine.

I have experienced a similar situation where it suddenly dropped below zero Fahrenheit in the deep south. I had a kerosene heater that kept everything warm, but don't forget, your neighbors won't have a source of heat. Pipes will freeze.

Hi, "Just John".... I have talked to the administration about them getting three big emergency generators (there are three buildings in the complex each with about 20 families) and even gave them a tentative design (I've been in construction management at a veterans hospital for 21 years) but getting them motivated is like trying to sell ice cream to an Eskimo. All the other tenants are concerned but few if any are doing much nor have I given them any ideas--I have a quick bug-out kit for when they accidentally (via stupidity) start a fire in the building!!!!!!!!!! As for frozen pipes I tried to motivate the administration for the generator (suggestion) reminding them that frozen pipes are their responsibility (everything INSIDE the walls belongs to them). They argued and many tenants realized that would end up in a long drawn out legal battle seeing as how many people have already informed their insurance companies of the administration lack of interest, motivation, and weak brainpan! But you are correct...any still water would freeze and cause irreparable damage...later. That means running water in ALL fixtures (and even that might not be good enough)... toilets, dishwashers, water heaters, ALL faucets (not just a couple)...etc etc. Of course as soon as the first pipe goes 'POP and if water then leaks/floods...the main to the building would be shut off. Then...it's where does one get potable water and sanitation removal. It could get really BASIC. We Americans are NOT ready!!! "Hope"... is sounding more viable than intelligence now. ha ha ha. Glad I'm 73!!

 

[Rednecktek]

Thanks, you are the second person to hint at smaller CFM. I will do this...been surfing the web. (will do some more testing at "the barn") Had another thought that if I could get lower CFM to work and of course it would be a DC Volt fan, then perhaps I could get a couple of batteries that would give me enough operational time to get me though the initial issues of no power for a couple weeks

And that is the key to doing anything with solar, reducing the draw will save you ssoooo much in system expense and complexity. Let's do some napkin math with smaller fans:

Big fans are 177Ah/day = 200Ah of LiFe = 400Ah of AGM/FLA

If we reduce those 200CFM to 20CFM, that's a factor of 10!

Small fans = 18Ah/day = 1/5 of a 100Ah Life battery = 1/3 of AGM/FLA

So if you can reduce the draw by using 20CFM fans, then a single 100Ah battery lasts 3 days (AGM/FLA) to 5 days (LiFePo4) per battery.

The other two advantages of LiFe over FLA are 1: no gas to worry about and 2: 25lb weight vs 60lb weight. The LiFe's are more expensive if you order online (About $350ish), but retail finding a 100Ah AGM you'll find that they're not that far different in cost (About $285 for the last one I bought).

The only way to really cheap out on those are to use the WallyWorld marine batteries at about $100ea which will off-gas, but they're cheap.

Now the easy way around that would be to put them out on the porch and just run the wires through the window with the solar panel wires. All the bus blocks would be outside (if you went with more batteries) but the controller and fuse block and switches and all could be inside where it's warm.

If you wanted you could also get 2 or 3 of the WallyWorld batteries and rotate them through the jeep if you need more charging oomph than what you can get off the back deck.

KISS OFF, right?