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DIY Solar Panels: Myths and Questions Answered

The author completed a 700 watt DIY solar project for his own rooftop and gained this authentic and valuable experience in the process.

Procurement of materials is an important part of a DIY solar panel project

Procurement of materials is an important part of a DIY solar panel project

Learn How to Make DIY Solar Panels

Making your own DIY Solar Panel can be a great hobby, especially if you have a technical mindset and prefer to do things, your own way. It can give you a priceless learning experience but, if you are serious about initiating a DIY Solar Project, you must be aware of the challenges that you may face during this determined endeavor.

This write-up elaborates on some of the most common questions and technical aspects a DIY hobbyist has to deliberate on, when initiating a DIY solar project.
In this article, I'll discuss:

  • The cost of DIY solar panels
  • How long it takes to make a DIY solar panel
  • Mono-Crystalline vs Poly-Crystalline cells
  • Half cut solar cells vs full 6' x 6' cells
  • How to measure energy generated
  • On-grid vs battery connected off-grid

Are DIY Solar Panels Cheaper?

If you are assuming that a DIY endeavor will save you some money as opposed to purchasing pre-fabricated solar panels, you might be mistaken.

With a DIY solar panel, you have to bear the costs of additional materials, other than the cheap solar cells that you purchased. Make sure you add all of them to the calculation and then compare the combined costs. These additional costs are included in the table below.

Cost* breakup of a 100 watt DIY solar panel.

*May vary depending on local conditions.

ItemQuantityEstimated Cost

Glass Sheet

9 sqft. / 100 watt panel

$ 10 - 15

Solder Iron + Soldering Tip

1

$ 3 - 5

Tabbing and Busing Wire

30 m tabbing wire and 2 m bus wire

$ 10 - 20

Wood or Aluminium Framing Material

According to perimeter of the glass sheet

$ 5 - 20 (Aluminum is more expensive)

Epoxy Resin

1 kg / 100 watt panel

$ 8 - 9

Silicon Sealant

1 tube

$ 3

MC4 Connectors

2 / panel

$ 2

DC 6 sqmm single core wire

20 meters

$ 10 - 20

Cost of Time Spent

10 hours

Varies person to person

Mono-Crystalline or Poly-Crystalline Cells for DIY Solar?

A very wise decision can be to use Mono-Crystalline cells instead of Poly-Crystalline cells. That is because, when you are prepared to make a significant investment of time and money in making DIY solar panels, you might as well consider spending a few extra bucks for increased current output from Mono-Crystalline cells - in the same amount of time and effort.

Mono-Crystalline cells are slightly more expensive than poly-cells but given that you have to pay the same amount of shipping charges, customs duties, and other miscellaneous costs for both, it may be worthwhile to bear the extra cost of mono-cells for increased current output.

A summary of the trade-off between Poly-Crystalline and Mono-Crystalline cells for DIY solar panels projects.

Poly-CrystallineMono-Crystalline

Cells Cost

less

high

Shipping Cost

same

same

Custom Duties Cost

same

same

Cost of Materials for Panel (Glass sheet, epoxy and tabbing wire)

same

same

Time Spent in Panel Fabrication

same

same

Mono-Crystalline cells will make a higher wattage panel in the same time and effort.

Mono-Crystalline cells will make a higher wattage panel in the same time and effort.

Half Cut Solar Cells vs Full 6' x 6' Cells

Half cut solar cells, that is size 6' x 3', are slightly more expensive than full 6' x 6' cells (due to extra effort spent in cutting them) but have advantages for DIY panels.

This is because panels can have a higher open-circuit voltage for the same amount of panel size, as more cells can now be arranged in series on the same glass sheet area. So, they double the panel voltage and half the current flowing through the panel.

Less current means fewer tabbing wires per cell are required to carry the reduced current.

  • A typical 6' x 6' cell has a maximum of 8 amperes of short circuit current, which roughly means 3 tabbing wires per cell.
  • A typical 6' x 3' cell has a maximum of 4 amperes of short circuit current, which roughly means 2 tabbing wires per cell will work.

Cells can have a 2-BusBar or 3-BusBar arrangement depending on the current flowing through the panel.

Cell SizeShort Circuit CurrentTabbing Wires Required per Cell

6' x 6'

8 Amperes

3 (minimum)

6' x 3'

4 Amperes

2 (minimum)

Half-cut cells generate less current so require less number of tabbing wires per cell. Usually a 2-BusBar arrangement is enough.

Half-cut cells generate less current so require less number of tabbing wires per cell. Usually a 2-BusBar arrangement is enough.

How Much Time Does It Take to Make a DIY Solar Panel?

Realistically speaking, from procurement of materials to soldering tabbing wire on solar cells and then doing epoxy on the finished panel, it can easily take 8–10 hours for fabricating just a 100 Watt panel. Even longer if you are not good at soldering and you may face additional difficulty in making a frame for the glass sheet.

Make sure you have enough time, and above all, patience, to conceive a four to five hundred watt project. To give you an idea of how much time it can actually take, I have provided a breakup of steps involved in DIY panel fabrication with the estimated time required.

Breakdown of activities for fabrication of a 100 watt DIY solar panel with estimated time required.

ActivityRequired Time

Procurement of Material (Glass Sheet, Epoxy and framing material)

Variable

Cleaning of Glass Sheet

10 - 15 Minutes

Cutting tabbing wire of required length

30 Minutes

Soldering tabbing wire on front side (-ve) of solar cells

1.5 - 2 hours

Arranging solar cells on Glass Sheet

1 hour

Soldering tabbing wire on backside (+ve) of cells

1.5 hours

Soldering BusBars

15 Minutes

Test the completed panel before applying epoxy

10 Minutes

Preparing and applying epoxy resin

1 hour

Fabrication of solar panel frame (Wood or Aluminum)

1 - 1.5 hours

Soldering tabbing wire on solar cells consumes the most time. Right: Testing a DIY solar panel in sunlight.

Soldering tabbing wire on solar cells consumes the most time. Right: Testing a DIY solar panel in sunlight.

How to Measure Energy Generated from DIY Solar Project?

It is extremely important to know actually how much energy your system has generated in order to:

  • Keep track of system efficiency.
  • Calculate the return on investment.

Most modern solar inverters come with android apps (like the one pictured below) that monitor kilowatt-hours generated and keep them stored on the cloud so that your data is not lost. Make sure the inverter that you purchase has this option - an app that can meter the units generated.

If the Inverter Does Not Have Wifi Monitoring

  • Option 1: Connect a DC watt-meter with the solar panels. This will help you read current, voltage, watt-hours, and ampere-hours (if a battery is present) in real-time.
  • Option 2: The SmartLife® app pictured below can also work independently with Wifi enabled switches that are available from Chinese manufacturers. Connect it on the inverters AC output and this is another cost-effective option.
Addition of a DC energy analyzer and monitoring apps will help you keep track of electrical quantities.

Addition of a DC energy analyzer and monitoring apps will help you keep track of electrical quantities.

Vital electrical parameters that should be recorded by your DIY Solar Project.

Electrical ParametersDescription

kWh ( Today )

Electricity units generation for today.

kWh ( Monthly )

Electricity units generation for month.

kWh ( Total )

Total units generated by system. (This is most essential for ROI calculation)

Watt Peak ( Wp )

Maximum value of power measured by DC watt-meter

Ampere Peak ( Ap )

Maximum value of current measured by DC watt-meter

Ampere-hours ( Ah )

If you are charging a battery through solar charge controller, it measures how much battery capacity you have charged or drained.

DC Current

Instantaneous DC current from solar panels or to load if it is DC.

AC current output.

Instantaneous AC current flowing towards the load or grid

On-Grid Vs Battery Connected Off-Grid DIY Solar Projects

Grid-Tied solar systems convert DC power into AC and feed it directly into the AC grid. The inverters are synchronized with the AC grid which acts as the primary load.

This essentially ensures that whatever AC power is generated will be either utilized over the AC mains of your house or will be fed back into the grid, where you sell it by way of net metering. This eliminates the need for storage and hence the batteries.

With a DIY project, costs and time are the most important consideration and this concludes that on-grid systems are more suited for DIY projects and the table below summarizes why this is the case.

A summary of additional works that may be required if you choose Off-Grid Solar as DIY project against Grid-Connected System.

On-Grid Solar SystemOff-Grid Solar System

Can save the cost of batteries.

Expensive batteries will be required.

Requires zero maintenance other then panel cleaning.

Batteries require periodic maintenance and checks.

No changes in house AC wiring are required.

Modifications in existing AC wiring may be required according to Off-Grid system capacity.

No restriction on appliances of daily use.

Usage of appliances may be restricted/changed according to system capacity.

How to Arrange and Connect DIY Solar Panels

Solar panels connected in series will give a higher voltage output.

Solar panels connected in series will give a higher voltage output.

Your inverters and panel configuration should be such that it maximizes the DC bus voltage, this way you will be able to:

  • Keep DC current to a minimum level and will save on heating and other system losses.
  • Reduce internal resistive losses in the solar panels.
  • Increase MPPT performance.
  • Increase system output in low light conditions.

This can be done by arranging solar panels in series rather then parallel to increase their voltage and keep the current same.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2021 StormsHalted

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