minimal solar electric system

[drbob]

I have an airplane hangar in northern Wisconsin that I would like to convert to solar electric.   The power company charges $39.00 monthly for hookup plus power usage.    I used under 200kw in the last year.  the total electric bill was $493 for the last 12 months  $26.00 was my power consumption  the rest was meter charges.   
I have an electric door lift and it draws 1,500 watts peak it is 120 volt.   the lights are 1440 watts, 4 rows of lights @360 watts each.     
I would like to have 3kw electric storage and I think 45 watts of solar panels should do the job.   
I would like some advice

[DamonHD]

Best to start off being clear about energy (kWh) and power (kW).

FWIW in (not so very) sunny London I have 2kWh of net storage to 50% DoD (400Ah at 12V) and I use it to run a tiny load (<10W continuous) and have ~200Wp of PV to keep it charged.

Look up sun hours in your area to see if 45Wh (0.045kWh) per sun-hour per day will even cover float and self-discharge and regulator consumption in winter (we get 1 sun-hour per day mid-winter here, and I need about 100Wh minimum per day to keep ahead, so 100Wp of PV minimum).

Rgds

Damon

[drbob]

I have an airplane hangar in northern Wisconsin that I would like to convert to solar electric.   The power company charges $39.00 monthly for hookup plus power usage.    I used under 200kw in the last year.  the total electric bill was $493 for the last 12 months  $26.00 was my power consumption  the rest was meter charges.   
I have an electric door lift and it draws 1,500 watts peak it is 120 volt.   the lights are 1440 watts, 4 rows of lights @360 watts each.     
I would like to have 3kw electric storage and I think 45 watts of solar panels should do the job.   
I would like some advice
200 kwh per year,  normal usage 10kwh per month

[lifer]

Your power consumption are not uniform distributed during the whole month - you just have peaks from time tot time (door+lights). So you have to design your energy storage (battery) for that peak consumption.

Your door has a nominal current rating of about 125A (for a 12V battery) and your lights are about the same. So, if you want to run them at the same time you need to extract 250A from your battery.

The manufacturers recommend a C/10 - C/5 discharge rate for the battery, thus you might need a minimum 1250A battery. Still you could extract more than C/5 but the available power will decrease.

10kWh of monthly energy, for a 12V/250A load means almost 4 hours of running on battery (durring the entire month). If you use the door/lights once a week, that means an hour at (almost) full power every time. To limit the battery discharge at 50%, you should have a battery rated at 12V/500A (theoretically).

To charge such a "monster" after a deep discharge (50%) you need a least a C/10 current, that means 50A.

From a 40W PV panel you could get a maximum of 2.5A (16V) and that's almost a trickle-charge for such a battery.

You have two solutions: to buy a larger capacity PV panels (not economically) or to have a much larger battery bank to not discharge them very deep, so you could keep them charged with a small current (2.5 - 5A).

There is a more economical solution for this situation: to buy a 2-3 kW gas generator and to use it just when you need it.

[Frank S]

First buy a Kill-a-watt meter & install it inline to the door opener .Log the start up watts the running times and the load watts
 Do not rely solely on the MFG data tag every installation of motors will show a variance from what is on the tag.
 I have a bandsaw  with a 1/2 hp motor  it will start and saw without a problem on my 1800w PSW AIMS inverter even if the wife is making coffee and the full sized fridge is running. But my 1/2 HP drill press will even trip my Xantrex 3000+ MSW
 my 3/4 Hp bench grinder will run on either as will the 1/2 HP  12x36 engine lathe
 What is your lighting Incandescent, florescent tubes, CFL, Mercury vapor, High pressure sodium, or LED? what is your total lumen output for your 1440 watts.
  $493.0 per year over 10 years is a considerable amount considering that only $260.00 would be actual consumption ignoring the likely hood that the price will be much higher in 10 years
   Short term expensive long term net savings could go something like this depending on current lighting
 Go with Super bright LED lighting  a single LE 12w A60 super Bright LED by Samsung will put out approx 1080 Lm / 4000k warm white light, that is a close equivalent to a 75 W incandescent bulb and should last up to 30,000 hrs  $10.00 up front becomes cheap
  400w of solar panels & a 30 amp PWm can be bought for around $500.00 to $600.00  @0 year life approx.
   2 L16 Trojan Batteries  from $250.00 to $350.00 each
  1 2500w PSW inverter   with a 3x 10 second overload  about any make or brand since it will not be used for continuous power  can be found reasonable If you can go with a low voltage with a toridal transformer if possible  because they have a higher overload capacity that a high voltage unit
 for about 4 to 5 times your current annual billing you would have a system that should cover everything  you are currently using and still have enough reserve power to use for other things.

[Frank S]

 Actually my previous post is not entirely correct

 You say you have 1440 w of lighting  3 rows @ 360 w each if these happen to be incandescent then about  680 Lumen would be  typical per bulb there are higher and lower outputs with 24 bulbs you would have 16,320 lumen of light
 the LE 12w A60 claims 1080 average. so in theory ONLY 15 12w super bright LEDs should put out the same amount of light
but say you currently have 24 bulbs drawing 1440 watts and replaced all of them with the 12w LEDs the current draw should be only 288 watts with 25,920 lumen nearly 10,000 more than before or with only 15 of them the the draw would be 180w  @ 16,200 Lumens nearly the same amount of light for 1/8 the current draw
 Doing that you could size the inverter just large enough to start U run the door lift even with the lights on.
 Plus since the L16 s like to be discharged to a greater depth once in a while you could go with the much less expensive T105s Torjans Or what is commonly called golf cart batteries GC2
 your door probably only cycles twice on any given day this would mean you could maybe get by with 200w worth of solar panels and a 15 to 20 amp PWM
 So right away by spending a couple hundred bucks in lights you cut your total needed out lay in half or more  then your could be looking at a 3 years worth of electricity billing for your system which should last 20 years except for the batteries which might net you 3 to 6 years per pair
  You would not have the excess of available energy like the L16s  & 400w of solar would yield though
 

[drbob]

OUCH!    A 1.5kw generator is probably the way I will go.    I have a 1500 watt generator now and it will lift the door with no problems.  Shutting off lights before I open the door is easy to do.

how about the option of  building a solar system that would provide 360 watts of lighting for the occasional walk into the hangar to get something say 15 minutes of use per visit?   A deep cycle marine battery a 750 watt inverter and a 45 watt solar panel with charge controller.    Harbor freight has lust the system ( on paper )   for under $200.00   less battery and inverter.    total cost would be under $500.00    I could live with that.   

[lifer]

I think it's a wise/economical/practical decision. Good luck!

[Bruce S]

For a nice long life nearly no hassle system; it would be best not to rely on the harbor Freight PV system. Grab something like a small system (kit) from solar blvd or wholesale or sunelec.
HF panels sometimes start loosing their rating very quickly.
While HF could get you a guick up system for about $150USD a system from say solar blvd would get you twice the panel for about an extra $100USD, that would be there in case you need that extra power. That and some good golf cart batteries from Sam'S would get you a pretty darn good system.
Just a Thought

[Mary B]

Harbor freight panels are junk. I had 6 and within 2 years 4 were bad. Connector boxes fell off, wire connections broke inside the panel frame...

[dnix71]

I can third that on Harbor Freight's panels being mediocre. Of mine, one cracked and two delaminated. HF used to be cheaper than commercial, but not so at least the last 5 years. HF panels do put out lots more power in cold weather, though, so winters in Wisconsin might get you more power than summers.

[drbob]

I guess that I could shop elsewhere.  I have had good and bad luck with harbor freight.   What they are wanting for their system seems too good to be true.   

[Bruce S]

I have had good luck with HF systems, back when they were a lot cheaper than mainstream stuff.
Both of my controllers are still working (older LED style and newer one with battery voltage display) only 1 panel is cracked and that's because a 67mph wind blew it off the stand before I had finished bolting it down :-( .
However for what is wanting to be a nice set-it-and-forget-it system; HF is no longer the best choice for the money IMO.
 

[Mary B]

A pair of these, a charge controller of choice, an inverter and battery and good to go http://www.solarblvd.com/Solar-Panels-&-Systems-12-Volt-Solar-Panels/c1_269/p2711/Two-Solar-Cynergy-140-Watt-12-Volt-Solar-Panels-with-Y-Connector/product_info.html I have 16 of those panels and so far they have been good.

[Frank S]

A pair of these, a charge controller of choice, an inverter and battery and good to go http://www.solarblvd.com/Solar-Panels-&-Systems-12-Volt-Solar-Panels/c1_269/p2711/Two-Solar-Cynergy-140-Watt-12-Volt-Solar-Panels-with-Y-Connector/product_info.html I have 16 of those panels and so far they have been good.

 Not bad, not bad at all for a small system For a charge controller there are 100s in the 15 to 30 amp range for very little cost
 If going with one that looks like this be sure to get one with round buttons not Oval not sure why but the round button models according to many are higher quality
 I have 2  CM60/24Z PWM charge controllers tied parallel both on input & output.  When I had only 1 it seamed to do a good job and often showed as much as charging amps I was worried of the eventual magic smoke Genie showing up  Now with 2 the combined output charge current often hits 70 amps  Not bad from a 1200w panel set

[drbob]

I just looked at what windynation has for sale.  I think I could get by with a 100watt kit that they have and a couple of marine deep cycle batteries.  My budget is $500.00

[XeonPony]

first off your system should be 24 vold, second monocrystaline panles are dirst cheap now days, 540w array with a mppt charg controller and a 400AH 24 vold bank and a good quality inverter you are set.

as the old saying goes ypou get what you pay for, but if the loads are on average very briefe then down that to a 200w array and a morning star 15mppt.