# how many solar panels?



## Countrybumpkin (May 12, 2002)

We have an add-on wood furnace, and we were looking at running it all winter from solar panels, so it is completly off the grid. the two blower motors each use 2.8 W running, about 6W @ startup.I figured it would be about 1632 W/Day, but uncertain just what size solar system is needed to run it. Probably out of our price range, but we are looking into it!


----------



## PD-Riverman (May 24, 2007)

I am confused-----at 2.8 watt per fan is only a fraction of the 1632 watt/day you mentioned--------you got something else running that you did not mention? Or Did You Mean 2.8 amps?






Countrybumpkin said:


> We have an add-on wood furnace, and we were looking at running it all winter from solar panels, so it is completly off the grid. the two blower motors each use 2.8 W running, about 6W @ startup.I figured it would be about 1632 W/Day, but uncertain just what size solar system is needed to run it. Probably out of our price range, but we are looking into it!


----------



## wy_white_wolf (Oct 14, 2004)

I come up with less than 140 watt-hours per day (2.8W * 24 hours * 2 fans) for both fans running continuously. The startup need doesn't really calculate into total usage because it's for such a short time.


----------



## TnAndy (Sep 15, 2005)

I bet you mean 2.8 amps......I have a hard time believing a 2.8 watt fan could move enough air to do anything in a furnace......2.8 watts is about the use on a smaller fan on a computer.

2.8 amps x 120v = 336w x 2 fans = about 700w, and if you use 1632w/day, the fans run a bit over 2 hours/day.

That sound right ?

Check your numbers, and come back....then we can talk solar needed.


----------



## Jim-mi (May 15, 2002)

If in fact they are 'muffin' fans your going to be in for a wake up call as to the amount of air that they DO NOT move.


----------



## Countrybumpkin (May 12, 2002)

Sorry! You all were right-I got the words mixed up...its 2.8 Amps per blower, of which there are 2, w/ it being 6.3Amps/blower @ startup!


----------



## TnAndy (Sep 15, 2005)

AND the length of time you will run them per day ?  ( we got to get watt/hours here before you can figure what you need in the way of a solar supply )


----------



## wy_white_wolf (Oct 14, 2004)

Just some basic calculations to give you a ballpark idea.

1600WH daily it is the load.

off-grid systems have a effeciency factor of about 33% so:

1600WH times 1.5 = 2400WH you need to produce daily

NW Ohio is the location. GIASMA for Toledo shows a low 1.2 hours insolation for December.

2400WH / 1.2H = 2000W is how big your array needs to be. 

2400WH / 12volts * 5 days = 1000AH battery bank at 12v

That would be 10 - 200 watt panels and @10 trojan T-105 batteries. A rough guess of $20k to $30K for the full system. 

WWW


----------



## byexample (Aug 28, 2009)

Wow, that's a really large load just to move some air around.

I recommend that you look at passive approaches to moving heat around in your home instead. Proper venting between rooms and floors can work wonders.

And ceiling fans can move plenty of air for way less energy than those blowers can. I think that wy_white_wolf's calculations look about right... $20k - $30k just to run the blowers on your stove.

There has got to be a better way...


----------



## wy_white_wolf (Oct 14, 2004)

It's not that big of a load.

It's that solar sucks that much in the winter in NW Ohio. Tha same load could be handled in SW Arizona for about $5k to $6K.
.


----------



## Countrybumpkin (May 12, 2002)

OMG!!! I never thought that I would be looking at an amount that large...thank you all who provided info-once i recover from the heart attack, I'll just forget the whole idea!


----------



## byexample (Aug 28, 2009)

wy_white_wolf said:


> It's not that big of a load.
> 
> It's that solar sucks that much in the winter in NW Ohio. Tha same load could be handled in SW Arizona for about $5k to $6K.
> .


LOL, seems like a large load to me.  We run on a fairly lean system here and load numbers like that make me dizzy and weak in the knees.


----------

