Category Archives: Solar

Off grid solar is, luckily, improving rapidly.
I started my build in 2010. In my area there were no good resources so I had to head to the internet and hack away on my own. I made a few minor mistakes, but mostly my 1kw system has performed above, way above, expectations. I have most of the amenities of modern life … I just can’t use them all at once or whenever I feel like. Luckily I don’t need air conditioning when the weather is cloudy. And if I have to wait for a sunny day to do laundry … well I’m drying my clothes on a line anyway.
These posts will document some of my trials and tribulations. I try to keep it light, hope you enjoy.

LFP is King — and I have proof

Vindication is mine

Dear readers, as you know I’ve been touting the energy storage benefits of lithium iron phosphate batteries (LFP) for off grid families who need reliable solar / wind / hydro energy storage from the moment I discovered a plug and play format earlier this year.

Sharing my realization on sites other than this one, I have been attacked, yes, and slandered, by a variety of what I have come to call “leadites.” Those who cling to this idea that solar power will remain in one fixed position.

Oh the battles I could tell you about. But today, dear reader, I found scientific proof to my hypothesis that LFP is the new best solar/wind off grid storage media.

To wit:

A comparison of lead-acid and lithium-based battery behavior and capacity fade in off-grid renewable charging applications
by Elena M. Krieger, John Cannarella, Craig B. Arnold
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ USA

Mwha ha hah … take this leadites …

Continue reading LFP is King — and I have proof

LiFeP04 vs Flooded Lead Acid batteries

Post from Simon, Karrak Farms, Australia

Creeky says: I thought this was interesting, so I bring this to the attention of those who are interested in LFP batteries for offgrid power storage.

LFP compared to FLA
LiFePO4  Flooded Lead Acid
Total Operating Voltage Range 14.4 – 11.2 15.5 – 10.5
Normal Operating Voltage Range, No Load 13.8 – 12.8 (90%-20%SOC) 15.5 – 12.0 (100%-50%SOC)
Normal Operating Voltage Range, C/8 Load 13.8 – 12.4 15.5 – 11.0
Normal Operating Voltage Range, C/2 Load 13.8 – 12.0 15.5 – 10.5
Max sustained charge rate 1C C/8
Recommended sustained charge rate N/A C/10
Sustained discharge rate 1C C/8
Peukert Coefficient ~1.02 1.2-1.6
Current efficiency >95% <90%
Lifespan ~10 years ~6 years
Warranty 5 year prorata (balqon) 5 year prorata (trojan)
Cost per kWh ~US$340 ~US$130
Cost per usable kWh ($/kWh/cycledepth) ~US$523 ~US$325
Cost per usable kWh per year ~US$52.30 ~US$54.20

Continue reading LiFeP04 vs Flooded Lead Acid batteries

LFP battery revolution changes off grid electric forever

I am weeping with joy as the Lithium Iron Phosphate battery (LFP or LiFePO4) completely changes off grid energy storage

Recently I stumbled across the Balqon LFP 9kw energy storage battery. It comes complete: battery management system, even a fuse, so it’s plug and play. The benefits look amazing, but how will it fare in comparison to my lead acid battery pack?

LFP battery pack
This Balqon LFP battery pack gives you 13 years of 4.5 kw daily energy use and you can buy it today. I’m in love.

Continue reading LFP battery revolution changes off grid electric forever

My off grid solar experiment

 Creeky’s solar system:
Or how I live the life of Riley off grid
Check out the coming Solar posts for more information about how I built my solar system.
Background:

When I started building my solar system in 2010 there were very few resources available in my part of the world. So I took the “build it and hope” approach.

  • First I built a solar shed with a rack that allows the solar panels to be easily adjusted for spring/fall, summer, winter, and big wind storm in the forecast. You can read more about the shed in the shed post.
The first cladding of the solar shed is complete. Let the rains come.
The first cladding of the solar shed is complete. Let the rains come.
  • Then I got some good batteries configured for 12 volts
12vbatterypack
These are Crown 395s. I have 6. 3 sets of two, in serial, in parallel strings. Works for me. And gives me about 1200 amp hours at 12 volts or 15kw of power. Which, with lead acid battery packs means about 3kw of reserve power.
  • I installed 1kw of solar panel power. Panels were in the 4 to 6 dollar a watt range. I was very fortunate to find high quality mono crystalline panels for $2/watt from a solar provider clearing inventory of demo panels.
    • As I’ve grown my needs I’ve upgraded to two mppt controllers so that I can have 2 kw of panels to charge those batteries. Currently (ha ha) I have 1.5 worth of panels
The solar shed
This is me spring of 2012. 1kw of panels working away.

Continue reading My off grid solar experiment

The solar shed: Part One

Building the shed

Your first quandry with any solar system is where the heck to put it.

Using a hybrid timber frame / regular wall I built an 8x8x10 frame for my shed.
Using a hybrid timber frame / regular wall I built an 8x8x10 frame for my shed. She’s solid as a rock boys.

You have to hang panels that are 3 feet by 5 feet in my case and weight 50 lbs each. You have to store batteries: 720 lbs of lead for me. And you need a safe dry spot for your charge controller, your inverter, your combiner boxes. And, if you’re like me, cheap, you have to do it on a limited budget.

What do you do? Here’s my solution:

Continue reading The solar shed: Part One