Solar pannels on the sawmill roof

[clousert]

A website that might be helpful in getting a small grant is www.greentagsusa.org
They have 58 small projects set up all over the US, and they take applications at any time.
I've never used them, just found this link on a websearch.

My Gempler's catalog handles solar panels.  Find them on the 'net at www.gemplers.com

A 1-foot x 3 foot panel costs $149 and produces 15 watts when the sun is out.  (15 volt strength).

The problem with solar is that it takes SO MANY PANELS to do much of anything.

If you have a battery bank of say, 4 car batteries, that is about 3200 amps at 12 volts, or 38,400 watts.  If you were running a 5 hp. motor, you will drain about 10% of your battery bank in one hour.  (746 watts = 1 hp).  By then you need to be replacing that 10% to avoid low voltage.  So you need enough panels to pump 3730 watts into the bank.  That is about 248 panels of the size mentioned above, at a cost of $36,952.

I'm not talking from experience, just from theory, because I have considered solar myself.

[jpgreen]

One thing to consider...

If you are paying over $5 a watt for any solar powered panel you are getting ripped off.  This includes most small cheap solar gizmo panels.

Large panels used for systems should be at least 75-100w or more.  The bigger and more powerful the panel, the less cost per watt produced.

"If you have a battery bank of say, 4 car batteries, that is about 3200 amps at 12 volts, or 38,400 watts.  If you were running a 5 hp. motor, you will drain about 10% of your battery bank in one hour.  (746 watts = 1 hp).  By then you need to be replacing that 10% to avoid low voltage.  So you need enough panels to pump 3730 watts into the bank.  That is about 248 panels of the size mentioned above, at a cost of $36,952."

This is not the way to look at solar/battery power.  No offense here, and I'm trying to find the best way to explain how this is example is not even in the ball park. 

There is no way you can run a 5hp electric motor on 4 batteries and drain only 10% in an hour. In fact 4 batteries wired in 12v will not even get the thing to grunt very long with a the huge inverter it would take to run it, which would need to be a 230v system sized to handle the amp surge.  I think you're confusing battery amps with battery "Amp Hours".

If your 5ph consumed 3730 watts continuos power or about 16 amps in 230v yes you would need about 4000 watts of panels with continuos sun to refill what was drawn in actual running time. BUT this large of a solar panel array is not necessary. There are ways around this.

What is needed foremost needed to be considered in any system is an inverter sized to handle your power needs.  Then even a battery bank of 4 batteries wired to match your inverter will work as a momentary holding point.

From there on you do need to keep those batteries filled to supplement the power drawn.  I run large draws with only 1000 watts of panels and 12- L16 batteries and a 4000 watt inverter. Most of the time the large draws are not continuos.  The batteries fully handle my use time, and later when the sun shines the 1000 watt array of panels catch up and charge the batteries.

Another way I supplement amps is I have a DC generating system I've designed- direct to battery bank charging system that provides 50 amps of pure power continuos, and only uses 1 gallon of diesel in 5 hours.  Now that's efficient cheap power on demand.

Running a 5hp electric motor with alt energy is not going to be cheap, but can be done and there are many ways to do it.  Some much cheaper than others.

[clousert]

I stand corrected.  As I said, I've never done this type of thing, but have considered it.  I know that a 5hp electric motor will require about 4000 watts of current, but I'm not sure how to figure the number of batteries I need to sustain that type of power.  My assumption was that a battery with 800 cranking amps, at 12 volts, was delivering 9600 watts of DC power.  I also assumed that DC wattage and AC wattage was the same, in terms of watts.  I know that there are power losses in conversions, and I didn't know how long a battery can sustain this drain.  I know a starter can render a battery useless in about 30 seconds.

If you can elaborate more on a setup for a 5 hp. continually running motor, I'd like to hear it.  Thanks!

[jpgreen]

We could work on this.  I'm just really busy right now.

Need more specs on the 5hp motor.  What will it be used for?  What phase, what amperage ratings- continuos, start up, etc. etc.

Then you have things such as wire run distances.

[clousert]

I still have to get the motor - it would be a single phase AC, 23 amps when running.  Wire distance: 20 feet from solar panels to battery bank/converter, then about 10 feet from bank to motor.  Running stationary chop saw for lumber.

Thanks for your time.