Sustainable Home: Finishing your Solar Power System

Disclaimer: please be careful when dealing with electrical components. Never have wires exposed, and always wear insulated gloves and clothing items. Also, this is for off-grid purposes only. Don't ever try and connect things to your home power grid. Only allow licensed electricians to do any work on your home, and get all proper permits. 

In our first segment in the sustainable home series, we left off making a solar panel at the cost of around $50 per 100 watts. In this post, we'll show you what to do in order to finish an off-grid Solar Power System, and it's typical costing.

Below is a diagram of what our final setup will look like, we'll then go over each individual component, their importance, and how much it will typically cost you. For now, we'll focus on only one panel, and one battery. We'll cover expanding your system later.

A- Solar Panel

The most essential part of your solar system (sort of).

If we're being real, it could be replaced with anything that generates dc power. Could be a bike, wind turbine, or a hamster wheel hooked up to an alternator.

As we covered in the previous post, you could either build your own on the cheap, or buy one directly from a manufacturer.

B-Diode

This little dude acts like a gate, letting current flow in only one direction: towards the battery. Current drain into the solar panels can cause battery levels to drop as well as some damage to your solar panels. Remember to place them oriented as seen in the diagrams (your actual diodes will have a white line on them too).

 Diode Symbols: The Triangle points towards the direction of allowed flow.

Diode Symbols: The Triangle points towards the direction of allowed flow.

$3.18

 

C- Charge Controller

These devices monitor your battery charge levels so that they stop charging when the batteries are full. Overcharging your battery can lead to damage and other unpleasant things, so this is pretty important. As seen below, there will be ports where you hook up your + / - wires of your solar panel, and the + / - wires of your battery.

$10.50

D- Deep Cycle Battery

A deep cycle battery is different than a normal car battery, they are specially made for many discharges and recharges, so they're often found used in RV's and boats. The batteries will typically have indications on what side is positive (+), and what side is negative (-). For the love of all that's holy, don't touch both sides at once without proper insulation, you could be in for a shock.

You will see batteries designated with voltage, and something called "Ah". This is short for Amp- hours. Simply put, if a battery is rated for 10 Ah, it means that at full charge, it can draw 10 amps for 1 hour before being depleted, or 5 amps for 2 hours, or 2 amps for 5 hours, or 1 amp for 10 hours, or 0.5 amps for.........I think you see the pattern.

For just charging laptops or cell phones, you're probably fine using a smaller battery, about 12-20Ah

$25.93

E- Inverter

This is where you plug in your phone charger, or other appliance. The inverter is responsible for transforming the battery's 12 volt DC current into 110V AC current. Sometimes if your appliance is pulling too much current, the fuses can blow on this thing, so make sure not to push it with your first build. Powering a computer or TV for a while isn't out of the question with a larger inverter, you'll just have to check the wattage on whatever you're looking to plug in.

When attaching the alligator clips to the battery, remember: Black to Black, Red to Red

$35.00 $38.99

For anything over 10 feet in distance, and carrying higher than 10 amps, you'll likely want to use thicker electrical wiring to and from your components. 14 AWG (american wire gauge) with 10 ft of circuit length will give you about a 3% drop in voltage.

 

If you're curious about what an appliance uses in terms of electricity draw, use this device to find out. It's pretty useful in determining what your solar power needs will be if you plan on using multiple appliances plugged into a power strip.

$18.38