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

[Get1949]

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

 

[740GLE]

Please tell me you have a CO monitor.

No stove should need a fan on to create a draft, sounds like without the fan you smoke up your apartment because of the lack of draft my guess is due to long horizontal run. There’s a reason why people don’t do this.

 

[Get1949]

CO? Of course I do.... Then again there is no smoke from the wood stove going onto the living space and all the piping and fan and electrical (DC) will be out on the porch (controlled from inside) and protected from rain. Friends that have seen it work (with the AC voltage--at "the barn") and have said this is better at controlling back draft and especially when the wood stove door is opened to feed it wood...than anything else seen with a normal chimney arrangement (over the peak of the roof) -- especially when starting and when the wind is not cooperating. Of course, what is needed is electricity...and those with typical wood stoves during an emergency... they don't need electricity! Without electricity in the depth of a cold freezing spell everyone here will have to move! So a long-term (week or more) blackout would be deadly!

 

[Get1949]

BTW. Pellet stoves can have fans and motors--one fan to blow warm air around the room, an auger to feed the pellets to the burn pot and a fan to move the hot exhaust gases to the outside of a building. In fact Tjernlund Products, Inc. makes a hot exhaust gas extractor: "Model AD-1 Auto-Draft Inducer" (google it). This is made to involve the hot stove gases with the fan blades...what I have arranged blows cold air around the exit end of the exhaust pipe causing a venturi effect and it (the cold fast moving air) pulls the hot gases out of its pipe...

 

[Get1949]

Also vertical pipe run is about 3 feet, horizontal run 6 feet and with no fan used at "the barn" the smoke exited OK...but opening the door to feed it allowed smoke to enter the living space but when the fan was turned on (testing using AC at the barn) the smoke immediately stop leaking out the door and air was drawn into the open door.... The stove itself is completely welded stainless steel. I JUST NEED TO HAVE DC VOLTAGE!

 

[markansas]

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

sorry i did not see this at first .. use a camping heater and not wood . gas . diesel . propane. here is a link and these can be bought for about 200

Propex vs Espar vs Webasto Heaters For A Camper Van Conversion

Propane, diesel and gas air heaters are an energy efficient way to stay warm all winter. In this guide we compare the most popular air heaters on the market, and give you tips and tricks for how to install them.

www.parkedinparadise.com

 

[Get1949]

OKaaaaa, I have the stove all I need is a way to get two 12VDC 2.5 amp fans to run via 12 volt batteries (like from a car/truck) or from solar...by charging the same batteries to run those mentioned fans.

 

[Get1949]

sorry i did not see this at first .. use a camping heater and not wood . gas . diesel . propane. here is a link and these can be bought for about 200

Propex vs Espar vs Webasto Heaters For A Camper Van Conversion

Propane, diesel and gas air heaters are an energy efficient way to stay warm all winter. In this guide we compare the most popular air heaters on the market, and give you tips and tricks for how to install them.

www.parkedinparadise.com

OKaaaaa, I have the stove all I need is a way to get two 12VDC 2.5 amp fans to run via 12 volt batteries (like from a car/truck) or from solar...by charging the same batteries to run those mentioned fans.

 

[Get1949]

Please tell me you have a CO monitor.

No stove should need a fan on to create a draft, sounds like without the fan you smoke up your apartment because of the lack of draft my guess is due to long horizontal run. There’s a reason why people don’t do this.

CO? Of course I do.... Then again there is no smoke from the wood stove going onto the living space and all the piping and fan and electrical (DC) will be out on the porch (controlled from inside) and protected from rain. Friends that have seen it work (with the AC voltage--at "the barn") and have said this is better at controlling back draft and especially when the wood stove door is opened to feed it wood...than anything else seen with a normal chimney arrangement (over the peak of the roof) -- especially when starting and when the wind is not cooperating. Of course, what is needed is electricity...and those with typical wood stoves during an emergency... they don't need electricity! Without electricity in the depth of a cold freezing spell everyone here will have to move! So a long-term (week or more) blackout would be deadly!

 

[markansas]

OKaaaaa, I have the stove all I need is a way to get two 12VDC 2.5 amp fans to run via 12 volt batteries (like from a car/truck) or from solar...by charging the same batteries to run those mentioned fans.

small 12 volt fan could be a old computer fan.. they draw very little . outside removable pipe. i was going easy and no wood.

 

[Get1949]

That square sheet metal part is basically what I have (I will have two of them to support the pipe front and back in the window to the porch-- mine is all rigid stainless steel...not flex... and also only 4 inch dia out of the stove!!). But that's not what this thread is all about. I NEED 12 VDC 2.5 amps for TWO fans (2.5 amps each) from a solar array with Battery storage (deep cycle Marine 12 VDC battery???). And all the goodies to hook it all up. See original post. I am very sure a computer fan will not have the CFM... besides I ALREADY have the ducted fans. THANKS...

 

[evilroy]

First question I have is why are you blowing cold air into the chimney, to get good draft you want a hot exhaust pipe and cold intake air, the other thing with cold air is that it is very moist so then you get creosote buildup.
What pipe diameter does your stove recommend, the longer the pipe the better the draft but you have to be well clear of walls trees and obstructions as they will cause a backdraft, personally....I dumped wood a decade ago (after 30 years use) and now use propane.

 

[Get1949]

 

[evilroy]

How big is your wood stove, how much area you need to heat?

 

[Get1949]

Evilroy and Markansas (and others)... It seems I've made this confusing so perhaps pictures will help: The black thing at the right is a high CFM AC ducted fan. 4A connect into 4B and blows the high volume (CFM) COLD air from outside on the porch up the silver tube and out the left high (upper) end at number 3. The orientation of the apparatus is leaning up against a wall so that it can been seen correctly...that is Number 1 IS the hot exhaust gas/fumes from the wood stove (it would be to the right about 3 feet as the pipe goes though the steel barrier fitted to the window nd then to the stove). See second picture... Number 3 shows the exit 6 inch dia pipe and inside it can be seen "Venturi around small pipe". The high CFM cold air coming up and around the small pipe causes a vacuum which draws the exhaust fumes out the small pipe and exits the entire amount of air hot and cold out to the atmosphere. Number 2 is sealed around number 1 loosely or will be fitted with gaps to allow some cold air in also depending on how hot the entire apparatus gets (to be determined at operation). The black ducted fan is 300 CFM, 37 watts, 115 AC voltage. I have ANOTHER set up that I am about to fabricate that is a "Y" connection that has two DC ducted fans both totaling 400 CFM (more than enough). In the upcoming fabricated "Y" the two upper parts of the "Y" will hold the 4" fans the hot exhaust pipe will be cut into the crotch of the "Y" and inserted to a depth of the "Y" branch and all the air from branches and center hot gas will exit a 6" dia exit at the bottom of the "Y".

As mentioned in the other posts the arrangement of the PIPING works and was tested (three times) at "the Barn" and so with TWO fans it will work even better (hope to control fan speed (RPM) with dimmer switch. BUT as mentioned in all post what I am having an issue with is GETTING THE NECESSARY DC VOLTAGE using solar panel, battery, and inverter/converter. It is the gaining of the DC voltage that is WHY I am seeking help!!!

 

[Get1949]

The stove is small, stainless steel, boils water easily, and would heat up the living room nicely...as it does heat up "the barn". I can NOT hook this up at my condo NOW to actually test it... as everyone would f-en freak out...! It will only be used in a complete power outage when it is obvious that power would not be restored for a considerable amount of time. By that time I start hooking things up to keep warm--the rest of the condo owners would be living in their cars (ha ha in February), moved away to friends with 'real' wood stoves, seeking community survival centers...OR...trying to break into my condo to keep warm (AND that would not be healthy for them to do that!!!).

 

[Rednecktek]

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.

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.

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.

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 real hard if you're cutting kindling in pitch black darkness.

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?" 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. Have you looked at Marine ductwork fans? Would a 100CFM fan still do the job? The smallest fan you actually need, 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.

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.

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.

 

[evilroy]

Try propane, heater, pro tank hose done for under $200.00, no cutting fitting windows or pipe and perfect for cooking and heat typically all for peanuts especially since it is for the occasional power outage, no smoke, soot, splinters, ants or new cuss words cause the dam fire won't start....been there done that!

 

[Get1949]

EvilRoy... Yes, I have a Mr. Buddy Heater....and would need to purchase many 1 lb tanks. Purchasing anything when there is no power is a game-changer, Having to store many 1 lb bottles in a condo or many 20lb propane 'bottles' is VERY problematic (aaaah, not doable...besides I have a source of free oak cured wood in train-loads...and can get to it clandestinely). Beside are you really that ____ Roy? Also everything is done except for the electrical...and the massive power outage. Duck-N- Cover Burt

 

[Get1949]

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.

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.

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 real hard if you're cutting kindling in pitch black darkness.

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?" 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. Have you looked at Marine ductwork fans? Would a 100CFM fan still do the job? The smallest fan you actually need, 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.

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.

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.

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...!!