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  • Writer's pictureSolar On EV

What is the “Solar Gain Calculator”

Updated: Nov 16, 2021

The “Solar Gain Calculator”, a simple online spreadsheet, would calculate mileage gain if a solar system were installed on an electric vehicle, created by Solar On EV. It calculates the mileage benefits and the estimated sizing for the solar system coverage area.

When you click on the tap “Solar Gain Calculator” or enter the URL, you’ll come to the screen below:

A Solar Gain and sizing calculator/spreadsheet to show the benefits/changes after solar installed on a EV.
A screen shot of the Solar Gain Calculator

It is the default screen from an interactive online excel spreadsheet. On this excel form, you’ll notice some color highlighted boxes, the “Green”, “Blue” and “Yellow”. Different colored boxes represent different types of data shown.

The “Green” boxes

The “Green” boxes are the only variables for calculation and only change via the dropdown list. The items you picked will be used for the calculation/estimation. There are only three “Green Box” on the calculator, and they are:

  1. EV models – the model of EV to use for the simulation according to their battery size, efficiency, and driving range

  2. Approx. Daily Distance Traveled – the daily average traveling distance for your EV to calculate the average daily power required.

  3. Solar Configuration – the size of the solar system (in terms of power output) to be used for the calculation.

The EV models

When you click on the “Pick an EV model” dropdown box, it shows a list of popular EV models available for the simulations, including Tesla Model 3, Cybertruck, Nissan Leaf, Porsche, Mercedes, MG, etc. Once you pick an EV model, the calculator will update with the appropriate EV’s info on the next category, “The EV model you chose”. The data for each EV model was acquired from Electric Vehicle Database and regularly updated. In the case of the EV model’s data acquired from other sources, the EV model will be asterisked (*).

The Approx. (or Average) Daily Distance Traveled

It is the average daily distance driven for your EV over the year. If you know about your daily commuting distance, you can use it for the calculation. Otherwise, you can determine your traveling distance by averaging out from your yearly mileage driven. It is only a guestimation, so pick a figure that best fits your situation. It will also immediately show you the annual total distance traveled from the figure you picked. Therefore, you can also choose the figure based on the annual distance traveled shown.

The Solar Configuration

It is the size of the solar system you choose, or you can fit onto your EV. When you pick a figure, it’ll calculate the daily and yearly “power output” in kWh and the surface area occupied in m2 for the solar system in the “Yellow boxes”. A figure for CO2 emission reduction is also estimated. Regarding the size of the solar system to pick, you can refer to the “How to – solar sizing” article on different ways to calculate the available surface areas or pick a size you like to experiment with the differences.

The figures we used are based on the panel performance of 200W per m2 and coverage factor of only 0.8; that is, the coverage area is 20% larger than the required area, a 1.20m2 of the surface area is required for the 200W panel rather than 1 m2. The overall “Daily Solar Power Output” is calculated on an average of 5 peak sun hours per day

The “Yellow” boxes

The “Yellow” boxes are “solar gain” calculated for the EV you picked after solar install. That is, the actual benefit figures if you’ve solar on EV.

The “Blue” boxes

The “Blue” boxes are results calculated based on the factory defaults of the EV you picked. They are the driving range, days before the battery depletes, and recharge frequency. The results are only for comparison with the calculated results after solar install.

The EV model you chose

This section illustrates some factory default info of the EV you chose and calculates the “EV Range” before solar installed in “Blue box” and “Approx. Solar Mileage Gain per Day” after solar installed in “Yellow box”.

Further down, it calculates your EV’s days of driving, recharge frequency yearly, and CO2 emitted over the year from the factory defaults before solar is installed in the “Blue box”.

If you have solar on your EV

Those are the calculated results (the yellow boxes), the comparison of figures with solar systems picked above, and figures calculated from factory defaults (the blue boxes). It clearly shows if there are advantages of solar being installed on the EV you picked.

Following is an example on choosing different criteria (the green boxes) would result:

For example,

Green boxes pick: “Tesla Model 3 Long Range”, “35” km, and “900W”.

It immediately shows the “Approx. distance traveled per year” is 12775km, “Daily PV Power Output” of 4500Wh, and the “Estimate system size” of 5.6m2 of coverage, etc...

Further down, it shows the factory default figures of EV models picked and the results before solar installation. For a Tesla Model 3 picked, the battery will last for 14 days and requires 26 recharges over the year.

After that, it shows the comparison figures with solar installed on the heading of “If you have solar on your EV”. In this case, the battery will last for 82 days compared to 14 only, 4 recharges only compared to 26 recharges required, and the driving range from 490km to 2874km.

If you’ve picked something different from the Green boxes, that is, a change of “35” km to “25” km.

The 900W solar system will last for “Infinite” days, and no more recharges are required. Therefore, the EV is totally “off-grid” based on the new figure of “25” km you chose from the Green Boxes.



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