figure my power input

[befnme]

Today I tested a theory. I have 2 used batteries from my f250, they are 660 cca each. I fully charged them to 100% then unplugged the charger. Using a 175 watt inverter I plugged up a box fan rated at 1.1 amps. If I am right that is 132 watts. It ran on high for 3hrs and 35 min. before hutting down. Now if I were using 4 of those batteries would I get 7hr of running time ?Also if I had my 2 solar panels @ 1.4 amps each hooked to them (2 batteries)at the same time they were drawing power how long would 1 fan last on high ? I am trying to figure what I need to run my home with XXXXXXX pulling current. How many betteries( I know I need deep cycle, I just had these lying around),how many panels, how many wind turbines, how many water turbines, how many inverters.

[TomW]

First, you are putting the cart in front of the horse.

The very first step should be determining your usage in KiloWatt Hours [KWH] This is on your electric bill some place.

Once that number is in hand, you cut it in half or better by practicing conservation.

After these steps are complete, then and only then can you even considering how much you "need" of everything.

That 1.4 watt panel [creates 1.4 watt hours per hour of full sun] probably won't keep an LED lit 24/7 so for "whole house" its useless, in fact, the 1.4 watt panel would hardly keep ahead of self discharge on the battery. 1.4 watts is pretty insignificant.  You probably buy 1000X that amount of grid power for 10 to 15 cents to use it for 1 hour . Prices vary. That math yields you would need 1000 hours of full sun on that panel to create a dimes worth of power. My math is far from exact but you should get the point from the numbers.

There you go, some homework so we can show you the way.

WRT doubling the batteries in parallel on the fan, yes 2X the batteries should roughly get you 2X the run time. Ignoring losses, of course.

TomW

[befnme]

Thanks, I actualy have 2 of those panels and 1 wind genny. haven't got everytthing up and running so i dont have any figures. PLus we are switching every light over to led. It is a little costly so thats kinda slow. I now have my children (10,12,15) to turn lights and tv's off while no one is around. It is a slow start but we are on the way.

[jonas302]

Changing bulbs and getting family involed is a great start!

Like Tom said you can usually find your comsumption on your power bill might help to get a watt meter to find  where the power goes don't forget the phantom loads

a direct tv box takes 25 watts turned off! tevo doubles that

best of luck

Jonas

[DamonHD]

You might find our power-saving efforts useful...

Having reduced our household (and home office) power consumption 5 fold to 6kWh/day, we can now cover maybe 30% of it with 1.29kWp of PV panel.

http://www.earth.org.uk/saving-electricity.html

Do dig out the kWh number from your bill as TomW says: unless you have gotten down to the low single digits per day solar is not going to be able to make much of a dent!

Rgds

Damon

[AbyssUnderground]

TomW,

You seem to have mis-read the above post. The panel is 1.4 amps not 1.4 watts.

[TomW]

Oops;

Oh, well. If you ever make a mistake I will be sure to point it out.

Its still pretty useless power as is. But you got to point it out, and thats what counts.

T

[finnsawyer]

Let's take a look at this.  Neglecting losses, the fan uses 132 watts continuous.  At the same time the panels are producing 2.8 times 12 or 33.6 watts continuous.  The batteries can only provide 132 times 7 equal to 924 watt-hours of energy no matter what.  With both the batteries and panels providing power the fan will work for N hours, the value of which to be determined.  We can write:

    132xN = 924 + 33.6xN.

That is, the energy used by the fan in N hours will equal the energy the batteries can provide, 924 watt hours, plus the power provided by the panels.  Solving we get:

    98.4xN = 924,   N = 9.4 hours.

Gee, not a bad increase.

[CmeBREW]

It sounds like you are well on your way. Getting the whole family involved is a must.

Be aware that for a renewable energy system, most agree that it is advisable to only run out 20-25 percent of a battery bank's total Amp hour rating.

One small point: It sounds like you ran out over 90 percent of the Amp hour power out of the two car batteries with the fan test.  Those two batteries probably won't last more than a month or two if you kept doing that.  It is the same with deep cycle batteries also. Batteries should last for years if you treat them right and only discharge 25 percent of their power (AH) ratings.

Damon's example of CONSERVING energy is very good example of the "Renewable energy lifesyle".  It is quite a different lifestyle than everyone else's. One must have accurate, realistic expectations of whats possible.

Everyone's specific situation and even 'Idea' of Renewable energy is somewhat different though it seems to me. It all depends if a person lives alone in a small one room cabin or if one lives in a 1400Sq. ft. house with wife and 3 kids.

The example given by Jonas302 about the terrible waste of just one direct TV box (while turned off) is a good one.  25 watts x 24 hours a day = 600 Watthour(!!) of power each day.

That is like letting a hairdryer run for half and hour each day for no reason!

My family has 4 of those horrible Direct TV boxes.  I at least turn mine on and off each day. And there are many other 'Phantom loads' that waste enormous power each day.

Another good example is that power wasting 132Watt fan you mentioned.

If that ran 24 hours a day it is 3168 Watthour. (Or; 3.1 KWH per day!!!)

I estimated that it takes 8 KWH per day for hot water (40 gal.electric hotwater tank/9000watts both elements) for 4 adult persons.

So many of those box fans are VERY substantial wasters of power.

You might consider making a Super-efficient 5Watt fan like I did here:

http://www.fieldlines.com/story/2007/3/10/23942/1876

It puts out about the same air but only at 120 Watthour each day!  I could run the thing on flashlight batteries all night if I wanted to!

There are many, many more ways to CONSERVE a LOT of power each day without much (or,any) sacrifice, if you put your mind to it.

So keep learning and conserving!  

Sounds like you are off to a good start.

[befnme]

Correction I have 2 panels 1.4 amps @ 30 watts each. Today I hooked my 175x350 watt inverter into my breaker box. I unhooked the hot and ground to 1 room in my house then hard wired it to my inverter. I ran my 27" tv and dish dvr with a battery charger turned to 12v 2 amp and  my batts never drained. they did sustain w/the 2 amp charge. Upon further thought I am leaning toward converting my wind turbine to a water turbine. I have a stream behind my home about 200 yds. It is approx. 9 feet wide 2.5' deep and runs about 2mph. I think if I dam it up to create more velocity directly in the middle then gear it correctly I will be better off.

[ghurd]

It wouldn't be too hard to beat the panels with hydro, in output per day.

One mini unit at half an amp would do it.

Then keep the panels and double your power.

G-