Under Construction


Steca 12V/5A Charge Controller
Trace C12 (At peter grubb hut)

Battery: (Deep Cycle)
See: Deep Cycle Batteries in Products

Misc Notes:
Don't put more than 4 strings of batteries in parallel. The batteries begin to struggle among themselves if you have too many in parallel. The weaker cells drain current from the stronger batteries,

From thread at www.wind-sun.com/ForumVB

Anyway, I have a small system which consist of the following PV components.

1 - 65 Kyocera Panel
1 - Steca 12V/5A Charge Controller
1 - 125 AH Energizer Deep Cycle Battery
1 - 1000 watts continous Go Power Inverter
1 - Go Power Class T Fuse Block (Rated 110A) between inverter and Battery

Well, you have to understand how much, how long, and what types of loads you are planning on using.... I don't know where you live, but if it is in a northern latitude / desert type area... You are looking at 2-6 kWhrs per day per sq.meter. Or, roughly 2-6 hours of full sun equivalent.

Your 65 watt array, will max out (in cool weather) typically somewhere around 57 watts max. Assuming 80% efficiency on charging and 80% efficiency on inverter and 2-6 hours a day of typical sun (winter/summer), you will be able to run a 1,000 watt inverter load for xx per day:

Inverter@1,000 watts = 57 watts * 2 hours * 0.8 * 0.8 / 1,000 watts per hour = 0.073 hours or 4.3 minutes per day (winter) Inverter@1,000 watts = 57 watts * 6 hours * 0.8 * 0.8 / 1,000 watts per hour = 0.219 hours or 13 minutes per day (summer)

A 100-125 amp*hour 12 volt battery will probably only supply about 10-20 minutes of power before damage occurs.

A bank of batteries (probably 20-40x the capacity of the single 100 amp*hour battery will probably run not 20-40x longer, but 40-80x longer because the batteries are more efficient at delivering power at a 20 hour rate than a 1 hour rate.

And, lastly, the type of load may define the type of inverter you can use--a modified sine wave inverter is cheap, but generates close to a square wave rich in harmonics which will cause overheating in many motors and appliances. A sine wave inverter (at 5+ x the cost and usually heavier) will do a much better job of running reactive and non-linear loads (motors and electronic loads would work better on a sine wave type inverter).

The 57 watt rating I gave you is an estimate of the power generated on a cool day with a bit of wind near high noon on a clear summer day--it is the number that California uses for calculating rebates as the manufacturer's numbers are way higher than anyone would typically find (except in cold/subzero conditions)...

Solar panels are "solar batteries" and only, at full sun (near noon with clean and cool weather) will output their rated voltage and current. Anything else will typically reduce their output dramatically. Typically, solar panels are only used in these types of applications:

1. Solar Panel charges a rechargeable battery during the day. The rechargeable battery supplies power at other times (either directly or through inverters, or a combination).
2. Solar Panel connects to Grid (AC utility power for home/office). If sun is up, panel/inverter "injects power" into the power lines (and can spin utility meter backwards.
3. Direct Solar Panel to load. Typically water pumps (from well/lake into tank, or circulating hot water to storage tanks, running swamp coolers, etc.). Useful when power is only need when sun shines or if other storage device for non-sun periods.

There is also another issue, the typical inverter cannot handle the wide voltage range available from a solar panel (a 12 volt panel can actually output between 17-23 VDC or so--probably high enough voltage to damage the inverter).

DIY Solar Panel:
DIY Solar Panels A Step-By-Step Guide
DIY Solar Panel Installation - Are Cheap Solar Panels Finally Here? - Popular Mechanics
Home Made Energy - DIY solar panel
  A long marketing pitch for a DIY guide for $47 that tells you how to build a 120 watt monocrystalin panel for $150.
  At digg.com they say it is a scam.

Home Made Energy - DIY solar panel
  A long marketing pitch for a DIY guide for $47 that tells you how to build a 120 watt monocrystalin panel for $150.
  At digg.com they say it is a scam.

Forum Advice:
From: Charging and Use - Harbor Freight 45 Watt Solar Panel Kit Community Forum
On my current system, I use the 45 watt harbor freight panels, + 1 Homemade 100 + watts panel.

My system current is connect to 2 walmart 27DC-6 12 Volt Everstart 115 amp hr , Deep cycle batts.. I ditched the HF controller

because honestly its a Junk controller.. Great for a power source connectiions with voltage regulation. But thats about it..

I just bought 10 Amp pwm HQRP Charge controller " EPIP SOLAR " But I am constantly using the power when the sun is shining bright for small wattage items, Plus I use LED lighting thru out my house. I also have these lights on at night for nice nightlights. But the HF cntroller is ok I guess if your just using the 45 watts of panels.. anymore than that. get a charge controller that works for the said amount of solar panels.

I do plan on Upgrading this charge controller to a MPPT model, But havent made any decisions on what Model or brand I will use yet.

SEI "Photovoltaics Design and Installation Manual"

Portable Solar Chargers and Types of Panels
Batteries Technology
Solar Electric Forums at wind-sun.com
Add Solar Power to All Your Stuff This Weekend at LifeHacker.com
Solar Energy International (SEI)
Deep Cycle Batteries in Products
Solar Panels in Products
Power Inverters
Charging in Tech
Solar Ray: Deep Cycle Batteries
Alternative + Renewable Energy | Northern Tool + Equipment

last updated 28 Apr 2008