EcoRenovator - View Single Post - P-p-p-ower shed: part two

creeky · 09-08-12, 04:20 PM

Here are a few pics and a general update on the "power shed" I built last year. (For those who missed it, the original "power shed" post is on page two or page three now).

As a quick refresh: the power shed holds 4 250 watt panels attached to 6 400 amp hour 6v batteries configured in a 12v system with 3000 watt pure sine inverter.

First, here I am, back on the farm Spring 2012 (this is a 3 season recreational property). I plug in the travel trailer and have power!

Note that the shed and the panels made it through the winter in excellent condition. My hinges were strong enough to hold up to the fiercest winter blast.

So: triumphs
* The shed is still standing.
* The mounting system is sturdy enough.
* The dock hinges allow multiple angles!

Now: tragedies
* The pwm controller was replaced with a MPPT controller (MS-MPPT 60).
I didn't realize that pwm was turning my 48v panels into 12v panels (I did sell the old pwm for what I paid for it).

I connect the new mppt controller to the wireless network and discover:
* highest power production is just over 6 kw
* given an average sunny day, easily produces 4 kw

Triumphs:
* I have run all my lights, kettle, blender, tv, microwave, water pump, battery powered devices, high speed internet via satellite and a 46" tv (I may watch too many netflix movies) strictly off of solar for the past 5 months.
* A 12v system is robust. In August I typically find my batteries in the a.m. at 12.55 or better (15% discharge). I have never had a morning with my batteries discharged more than 12.5. I do turn off the internet modem when I go to bed. It saves 30-35 watts/hr.

Tragedies:
* A 24v system with two more batteries and two more panels would have run an electric fridge and an air conditioner. So close!

Note: on occasion the 1000kw system ran an 8000 btu seer 9.9 air conditioner, usually from 3 to 7 p.m. Cooling the "house" during the hottest part of the day. This did draw down my batteries a bit. With a 1500 watt system the a/c would run completely off the panels. I could get another controller, mate it to the current one, and run two additional panels or; go 24v (still requires two more solar panels).
I turn the a/c on only after the batteries have gone to "float." This means they are fully charged. I turn the a/c off once the panels are out of the sun. The "house" is also out of the sun.

In summation:
Anyone looking to go offgrid with modest electrical needs will be well served by a 12 volt system with 1200 amp hours of battery storage and 750-1000 watts of solar panels.
A solar shed is a good idea.

Recommendations:
* Go 24 volt and up your solar to 1500 watts. Now you can have a modern electric fridge/freezer. My propane fridge accounts for the best part of my propane consumption (aprox. 40 lbs/mo.)
* add too many solar panel watts. Haze, clouds, dirt on the panels all conspire to limit output power. So more panels is better.

09-08-12, 04:20 PM	#1
creeky Journeyman EcoRenovator Join Date: Jun 2011 Location: a field somewhere Posts: 304 Thanks: 64 Thanked 44 Times in 31 Posts	P-p-p-ower shed: part two Here are a few pics and a general update on the "power shed" I built last year. (For those who missed it, the original "power shed" post is on page two or page three now). As a quick refresh: the power shed holds 4 250 watt panels attached to 6 400 amp hour 6v batteries configured in a 12v system with 3000 watt pure sine inverter. First, here I am, back on the farm Spring 2012 (this is a 3 season recreational property). I plug in the travel trailer and have power! Note that the shed and the panels made it through the winter in excellent condition. My hinges were strong enough to hold up to the fiercest winter blast. So: triumphs * The shed is still standing. * The mounting system is sturdy enough. * The dock hinges allow multiple angles! Now: tragedies * The pwm controller was replaced with a MPPT controller (MS-MPPT 60). I didn't realize that pwm was turning my 48v panels into 12v panels (I did sell the old pwm for what I paid for it). I connect the new mppt controller to the wireless network and discover: * highest power production is just over 6 kw * given an average sunny day, easily produces 4 kw Triumphs: * I have run all my lights, kettle, blender, tv, microwave, water pump, battery powered devices, high speed internet via satellite and a 46" tv (I may watch too many netflix movies) strictly off of solar for the past 5 months. * A 12v system is robust. In August I typically find my batteries in the a.m. at 12.55 or better (15% discharge). I have never had a morning with my batteries discharged more than 12.5. I do turn off the internet modem when I go to bed. It saves 30-35 watts/hr. Tragedies: * A 24v system with two more batteries and two more panels would have run an electric fridge and an air conditioner. So close! Note: on occasion the 1000kw system ran an 8000 btu seer 9.9 air conditioner, usually from 3 to 7 p.m. Cooling the "house" during the hottest part of the day. This did draw down my batteries a bit. With a 1500 watt system the a/c would run completely off the panels. I could get another controller, mate it to the current one, and run two additional panels or; go 24v (still requires two more solar panels). I turn the a/c on only after the batteries have gone to "float." This means they are fully charged. I turn the a/c off once the panels are out of the sun. The "house" is also out of the sun. In summation: Anyone looking to go offgrid with modest electrical needs will be well served by a 12 volt system with 1200 amp hours of battery storage and 750-1000 watts of solar panels. A solar shed is a good idea. Recommendations: * Go 24 volt and up your solar to 1500 watts. Now you can have a modern electric fridge/freezer. My propane fridge accounts for the best part of my propane consumption (aprox. 40 lbs/mo.) * add too many solar panel watts. Haze, clouds, dirt on the panels all conspire to limit output power. So more panels is better. Attached Images Last edited by creeky; 09-20-12 at 07:00 PM..