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Basic Solar Power Tutorials

Connections

Connecting the Charge Controller

After you connect the Solar Panels to the input terminals of the Charge Controller using the chart at the end of Correct Cables and Wire Sizes, you can use the same size wire to connect the Charge Controller output to the batteries since these wires will carry no more current than the solar panel wires and will probably be located pretty close to the batteries anyway.

Connecting the Power Inverter

The Power Inverter is next. Both the Power Inverter and the Batteries require the largest wires in the system. During operation, the AC produced by the Power Inverter draws considerable amps from the batteries. Not only are very large wires required, but they should not exceed 6 feet in length to reach the batteries. These wires are like the large battery cables in cars. Use the largest size possible. An AC appliance drawing 10 amps (like a microwave or vacuum cleaner) will require 100 amps at 12 volts DC. Even large cables will get warm. Don't skimp here.

Connecting the Solar Panels

There are three types of wiring configurations that are relatively easy to learn. Once mastered, the job of wiring becomes easy as pie. The three configurations are: 

1. Series wiring 2. Parallel wiring 3. Combination of series/parallel wiring
Series wiring Parallel wiring Combination of series/parallel wiring

In any DC generating device such as a solar panel or battery, you will always have a negative (-) terminal and a positive (+). Current flows from the negative terminal through a load to the positive terminal. 

Series Wiring

To wire any device in series you must connect the positive terminal of one device to the negative terminal of the next device

Series wiring

* Note:

  1. When you wire panels in series the individual voltages of each panel is additive. In other words if each panel in the above example can produce 12 volts, then 12 + 12 = 24 volts. 
  2. The second important rule to remember about series circuits is that the current or amperage in a series circuit stays the same. So if these panels each had a rating of 12 Volts/220 Amp hours then the total value of this series circuit would be 24 Volts/220 Amp hours.

Remember the Voltage in a series circuit is additive and the Current stays the same.

Parallel Circuits

To wire any device in parallel you must connect the positive terminal of the first device to the positive terminal of the next device and negative terminal of the first device to the negative terminal of the next device.

Parallel wiring

* Note:

When you wire panels in parallel the resulting Voltage and Current is just the opposite of a series circuit. Instead the Voltage in a parallel circuit stays the same and the Current is additive. If each panel in the above example had the potential of producing 350 Amp hours then 350 + 350 = 700 Amp hours, the Voltage would stay the same.

Remember the Voltage in a parallel circuit stays the same and the Current is additive.

Series/Parallel Circuits

Hold on to your hats because here's where it gets a little wild. Actually you've already learned all you need to know to under stand series/parallel circuits.

A Series/parallel circuit is simply two or more series circuits that are wired together in parallel.

Combination of series/parallel wiring

In the above example two separate pairs of 6 Volt panels have been wired in series and each of these series pairs have been wired together in parallel.

Remember in parallel circuits the current is additive so you increase your run time or Amp hour capacity or in the case of solar panels, you increase your charging current by wiring the solar panels in parallel. Since we need 12 volts and have 6 volt panels on hand, wiring the panels in series allows us to get the 12 Volts.

An easy way to visualize it would be to start by wiring the panels in individual sets that will give you the voltage that you need. Let’s say that you need 24 volts but have 6 volt panels on hand. First wire four of the panels in series to get 24 volts. (Remember wire in series to increase the voltage) and continue to wire additional sets of four panels until the panels are used up.

Next wire each series set of four panels in parallel to each other (Positive to positive to positive and so on and then negative to negative to negative and so on) until each series set is wired together in parallel. If each series set of panels equals 24 Volts at 350 Amp hours then five series sets wired to each other in parallel would give you a 24 Volt @ 1750 Amp hour panels pack.

Remember: In a series circuit current stays the same but the voltage is additive. In a parallel circuit the voltage stays the same but the current is additive.

Connecting the Batteries

The batteries are last. They will also require very large cables like the large battery cables in cars. The full current to the loads and also the full charging current flow thru the entire battery bank. Connect all the batteries with large high quality cables. Showing below is Battery Wiring Diagrams tutorial for examples of Series and Parallel wiring techniques:

  1. This diagram shows a simple parallel circuit to increase current or power. Assume that we are using 12 volt batteries. The power of all 3 batteries add to give us the effect of a battery 3 times as powerful but the voltage stays the same at 12 volts. Parallel wiring increases current but the voltage does not change. This is the wiring used when jump starting a car for example.

  2. This diagram shows a simple series circuit to increase the battery voltage level. The voltage of all 3 batteries add to give us the effect of a battery 3 times the voltage or in this case a very large 12 volt battery. In this circuit the current is the same as the current in just 1 of the batteries. But since the 4 volt industrial batteries are very large, we have in effect created a huge 12 volt battery.
  3. This diagram shows a combination series and parallel circuit to increase both the battery current and voltage level at the same time. The left to right series connection add the two 12 volt batteries to make 24 volts. And, since we did this 3 times and then connected each group of 2 (now 24 volts) in parallel we end up with one very large 24 volt battery. It has twice the voltage of a single 12 volt battery and 3 times the current or power because all 3 groups are wired in parallel.

Solar Energy Systems wiring diagram

These diagram examples could represent 12, 24, or 48 volts systems. The basic wiring configuration would be the same for any voltage system. These diagrams are meant to give a general idea of typical system wiring. Certain grounding and fusing circuits have been omitted from the wiring diagrams for clarity.

* Note: based on 100 watt solar panels and a 5 hour solar day.

DISCLAIMER : Always make sure that all of your equipment is properly fused and grounded for safety. Also, be sure to read and follow the advice and instructions that come with your equipment. These example diagrams, while reasonably accurate, are not meant as a substitute for the recommendations of a licensed electrician. These examples are a guide only and are meant to demonstrate how typical system components are connected together.



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