Solar Barn! Brand new, need some advise

[Spartan]

Hey Everyone ~

Sorry if I'm about to ask stupid questions, but this solar project is fun, but confusing as heck. Brand new to this and need some help.

We have a two stall barn & tack room in Cumming, GA that I decided to go solar. Here's what I have running so far:

One 60W panel and Two 15W panels (Sunforce) 90 Watts in array on the roof
Two 400w Inverters
10 awg wiring (40 feet total)
One 7amp 105W Controller
Two deep cycle batteries in parallel

Here's what I'm trying to power up, to start:

One 1.7 Cubic Foot NuCool Refrigerator (sodas and MY Beer)
Two 20" Box Fans (one in each stall for the hot days) Run time from 7am to 5 pm, daily
One 15w Eco lightbulb in our tack room (only in the evenings when needed, minimal time)
One plug in radio (ballgames and some music)

Here's my issue -
I followed the directions installing all of the components. Checked volts of the panels (separately, and in array), it's at 18.5 volts. Checked it after the controller was installed, then began running the refrigerator and box fans. Within about four hours, the batteries were at 11.7 volts, so I shut everything down.

I initially had a 12 v 30 amp controller, but it would not charge, so I purchased a 7 amp to just try and get off the ground. It seems to be working, because the charge in increasing to 12.75 watts today.

I know that I'm probably leaving a bunch of important information out, but I'm trying to grasp the concept on how everything works and if what I have being powered is too much. Should my batteries conceptually be for backup?

Any help would be greatly appreciated. My beer is back in the grid refrigerator!
Thanks, Mr. Spartan

[Sunking]

Welcome aboard

Well you described the picture pretty good and very simple to troubleshoot. You simply do not have enough of anything to run what you want.

With you panels being miss matched more than likely cuts your power output from the panels way down. Even if they are matched up you are around 500 to 1000 watts short.

As for the batteries and charge controller, not even in the ball park to being close to large enough.

What you have is just about enough to run the 1 light and radio. Fridge and fans gotta go.

[Spartan]

Wow! Thanks for the information. About as rookie as it gets, but willing to learn.

So, what would be your minimal list of equipment to get what is needed, and recommendations? This also helps me understand the concepts better.

[Sunking]

Wow! Thanks for the information. About as rookie as it gets, but willing to learn.

So, what would be your minimal list of equipment to get what is needed, and recommendations? This also helps me understand the concepts better.

Spartan that is a very hard question to answer because I do not know your location or how many Kwh per day you need.

But here is a rough idea for a system that produces 1 Kwh of electricity per day which is about what your refrigerator uses.

Solar Panel wattage = 500 watts
40 Amp PWM charge controller
12 volt 400 AH battery

[Spartan]

Location - Atlanta, Georgia

I just returned from our barn and I gathered my info. Please assist on these calculations:

One 15W light bulb - .50 hr a day at most
Two Galazy 20" Box Fans 3 speed - 90 watts (on high), 1.1 amps each - 9 hrs a day usage
One Nucool 1.7 cu/ft Refrigerator - 130 watts, 1.6 amps - Continuous
Radio 120v, 60hz, 13 w - Maybe 2 hrs use a day.

My (2) 12v batteries are deep cycle marine batteries - 685 Marine Cranking amps, 550 cold start amps, 140 Reserve amps.

I currently have the 3 panels = 90Watts
7amp charger controller

What do i need to make this work? Is there a different way to configure the batteries to get more out of them. Trying to stay within my means.

Any help would be appreciated.

Thanks,

Spartan

[Sunking]

Location - Atlanta, Georgia

One 15W light bulb - .50 hr a day at most
Two Galazy 20" Box Fans 3 speed - 90 watts (on high), 1.1 amps each - 9 hrs a day usage
One Nucool 1.7 cu/ft Refrigerator - 130 watts, 1.6 amps - Continuous
Radio 120v, 60hz, 13 w - Maybe 2 hrs use a day.

OK that is exactly what I need to know to fully design the system. I assume the fans will only run from say May to October.

Power usage:
15 watt light x 1 hour = 15 WH
2 fans 180 watts x 9 hours = 1620 WH
1 frig 130 watts x 24 hours x .4 duty cycle = 1250 wh
1 Radio 13 watts x 2 hours = 26 WH

Total = 2911 watt hours.
Efficiency adjustment using MPPT Controller = 1.5 x 2911 wh = 4366 WH round up to 4400 watt hours daily usage.

Battery AH vs Voltage:
12 volts = 4400 wh x 5 / 12 volts = 1833 AH
24 volts = 4400 x 5 / 24 volts = 916 AH
48 volts = 4400 x 5 / 48 volts = 458 AH

Solar panel Wattage required:
4400 wh / 5 hours = 880 watts

MPPT Charge controller requires vs Battery voltage:

12 volts = 880 watts / 12 volts = 73 amps
24 volts = 880 watts / 24 volts = 36 amps
48 volts = 880 watts / 48 volts = 18 amps

Here is my suggestion. You will not like the first part. Sell whatever you have already because it is of no use.

Run the system at 24 volt battery with a 80 amp charge controller. This will allow you to grow the system up to 2000 watt panels @ 24 volts, or 4000 watts @ 48 volts.

[milezone]

Trust me take Sunking's advice. I had close to the same setup you have now. I since took the advice and went 24 volts, MPPT 60amp controller, and I have noticed a huge increase in my power.
This was keeping the same 480 watts of solar panels (4 - 120 watts each).

Milezone

[kathys]

Kathys

I have the same issue but I am only running 2 AC box fans. I understand I will need a constant power source to the battery. I am considering using a solar panel to keep the battery charged. I have been told to use a 5 watt Solar trickle charger panel and another person told me 5 watts is not enough and a trickle charger will not work. After reading this article I am hoping you can tell me what I need to convert DC to AC to run the fans 12 hours a day. The fans are 120V. Thanks you

[Sunking]

I have the same issue but I am only running 2 AC box fans. I understand I will need a constant power source to the battery. I am considering using a solar panel to keep the battery charged. I have been told to use a 5 watt Solar trickle charger panel and another person told me 5 watts is not enough and a trickle charger will not work. After reading this article I am hoping you can tell me what I need to convert DC to AC to run the fans 12 hours a day. The fans are 120V. Thanks you

2 box fans? How much power do they consume? How many hours per day will they run? Where are you located?

A 5 watt solar panel will not even run a 5 inch muffin fan to cool your computer for 1 hour.

Power is measured in watt hours. Formula is watts x time (in hours) = watt hours. It works just like money and hourly wages except solar battery power has very high taxes called inefficiency. If you make $5/hour, and work for 5 hours per day you make $25/day but it cost you $2500/day to live; guess what happens to you? Oh yeah the government wants 50% of your income in taxes so you have to make that up too, so you need to make $5000/day to stay afloat but you only make $25/day.

The difference is energy is not like money. You cannot take a loan, use a credit card, or print fake money. You either have it, or do not have it, no exceptions, no mercy. Pure law of physics, no cheating can be done.

[kathys]

Second Try

2 box fans? How much power do they consume? How many hours per day will they run? Where are you located?

A 5 watt solar panel will not even run a 5 inch muffin fan to cool your computer for 1 hour.

Power is measured in watt hours. Formula is watts x time (in hours) = watt hours. It works just like money and hourly wages except solar battery power has very high taxes called inefficiency. If you make $5/hour, and work for 5 hours per day you make $25/day but it cost you $2500/day to live; guess what happens to you? Oh yeah the government wants 50% of your income in taxes so you have to make that up too, so you need to make $5000/day to stay afloat but you only make $25/day.

The difference is energy is not like money. You cannot take a loan, use a credit card, or print fake money. You either have it, or do not have it, no exceptions, no mercy. Pure law of physics, no cheating can be done.

I'm not sure why I deserved that. I am only trying to find out what I will need to use Solar power to run 2 120V fans for 12 hours. You seemed to work very well with the person before me. What did I say or do wrong in your eyes to not warrant help? So Sorry.

[Mike90250]

I have the same issue but I am only running 2 AC box fans. I understand I will need a constant power source to the battery. I am considering using a solar panel to keep the battery charged. I have been told to use a 5 watt Solar trickle charger panel and another person told me 5 watts is not enough and a trickle charger will not work. After reading this article I am hoping you can tell me what I need to convert DC to AC to run the fans 12 hours a day. The fans are 120V. Thanks you

Assume each fan is 90 watts
180 watts x 12 hours = 2160 watt hours consumed by fan

add 20 % inverter losses brings it to 2592Wh
add 30% battery recharge losses 3370Wh
divide by 5 usable sun hours in a day = 675W harvested per hour

and since solar PV only puts out 80% of nameplate, when in the field and not the lab, you need 850W of PV array


850W of PV @ $2 watt $1700
60A charge controller $500
Pure sine wave inverter (fan motors will overheat and buzz on a mod-sine inverter) $300
Batteries, to hold 7Kw of power (about 2x usage, so you don't discharge below 50%)
single 12V 100ah battery = 1200wh comes up to 6 batteries @ $100 each for the cheap ones. $600

So a little more than $3,000 to run 2 fans. Or buy a long, long extension cord.


Sorry, it's very hard not to laugh, and snicker when someone has been totally misled by the greenies. Whoever told you a 5w panel, you should force them to read this post, and then have them explain what they were smoking. As Sunking said, a 5w panel won't even run a computer fan.

So there goes another 20 minutes.

[Sunking]

I'm not sure why I deserved that. I am only trying to find out what I will need to use Solar power to run 2 120V fans for 12 hours. You seemed to work very well with the person before me. What did I say or do wrong in your eyes to not warrant help? So Sorry.

Because you have supplied no useful information and I am trying to wake you up.

All I know is you have 2 box fans you want to run them 12 hours per day. Energy is very simple grade school math like hourly wages.

Watt hours = Watts x Hours.
Wages = Hourly Rate x Hours.

So you have a 5 watt panel. I assume you live in outer space where the sun shines 24 hours per day at 100% efficiency which means that 5 watt panel can only generate 5 watts x 24 hour = 120 watt hours.

However for those of us living on earth with real box fans that consume say 100 watts each with 2 of them running 12 hours per day consume 2 units x 100 watts x 12 hours = 2400 watt hours. Since being confined to earth and depending on where we live we only get at best 6 sun hours each day and can only harvest with about 50% efficiency. Tha means we need to harvest 5000 watt hours per day, and with only 6 hours at best in July in Phoenix we need at least 5000 wh / 6 hours = a 833 watt solar panel and 250 pounds of battery. If we live any where else other than Phoenix or run the fan other than the month of July we will need even a large solar panel of more than 1000 watts.

So without knowing your location and how much power the fans consume all I can do is tell you is 5 watts is fantasy, and try to wake you up to reality.

OK my bad. Do you want to start over with real information?

[Sunking]

Sorry, it's very hard not to laugh, and snicker when someone has been totally misled by the greenies.

Or Obama and voted for him. At least Clinton II (aka Hilary) understands management, budgets, and can control chaotic behavior.

[Russel]

12v fans are the solution.

you would be better off just getting "direct" dc fans, still not cheap, but cheaper maybe $130 bucks

http://www.therenewableyou.com/SolarFan_adam@try.com_08_10_02.pdf

describes the process.

his cost for a 20w panel is wayyy too much you can get them here

http://www.sunelec.com/sun-solar-panel-20-watts-1870-vmp-p-843.html

for $55

of if you are going to run two fans just get the 50W panel for about double the price.

[kathys]

Thanks Mike

Assume each fan is 90 watts
180 watts x 12 hours = 2160 watt hours consumed by fan

add 20 % inverter losses brings it to 2592Wh
add 30% battery recharge losses 3370Wh
divide by 5 usable sun hours in a day = 675W harvested per hour

and since solar PV only puts out 80% of nameplate, when in the field and not the lab, you need 850W of PV array


850W of PV @ $2 watt $1700
60A charge controller $500
Pure sine wave inverter (fan motors will overheat and buzz on a mod-sine inverter) $300
Batteries, to hold 7Kw of power (about 2x usage, so you don't discharge below 50%)
single 12V 100ah battery = 1200wh comes up to 6 batteries @ $100 each for the cheap ones. $600

So a little more than $3,000 to run 2 fans. Or buy a long, long extension cord.


Sorry, it's very hard not to laugh, and snicker when someone has been totally misled by the greenies. Whoever told you a 5w panel, you should force them to read this post, and then have them explain what they were smoking. As Sunking said, a 5w panel won't even run a computer fan.

So there goes another 20 minutes.

I appreciate your time. I was able to talk with someone in person yesterday and they went through the formula and told me exactly what they needed to know in order to help me. Thank you for your time. I understand enough to know solar is not my solution. Have a great weekend.