Solar Energy * Solar Energy System Sizing * Solar Panel Estimator * Solar Battery System Estimator * Green Energy

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Solar Panel and Battery System Estimator

Use this estimator to get an idea of how many solar panels you will need to replace all of your current power consumption. It will also calculate how many storage batteries you will need to store that power.

Note: You DO NOT NEED TO HAVE BATTERIES in your solar system in order to make it work. You can purchase a grid-tied system which will complement your grid power with solar power. It allows the consumer to draw power from the grid when their system is not generating enough electricity to power your home, like at night or a cloudy day, thereby eliminating the need for batteries. This also allows individuals with surplus power (wind, solar, etc) to sell the power back to the utility. This is sometimes called "spinning the meter backwards" as that is what literally happens.

Select closest Size and Use factor for each Item

Just click the 'Calculate' button below to see the pre-selected default settings which approximate the typical usage for a small household of 2 persons. Or, select the choices that apply to you from the drop down lists then click the 'Calculate' button below.

Number of Panels/Batteries Needed
Number of Solar Panels (80-100 watt)  
Number of Batteries (12v @ 105 AH)  
* NOTE: The number of Solar Panels required is based on a typical 90 watt panel. The batteries are assumed to be standard 12 volt @ 105 amphours.

System Sizing Estimator

Select size in cubic feet. With an icemaker, select the next larger size.
How many persons are using it? 2 persons is average use (35% run time).
Select TV type & Screen Size.
How many hours per day is the TV on?
Select a MicroWave Oven based on Power rating (Wattage).
How many minutes per day is the MicroWave used?
Add wattage of lights in all rooms. (four 60 watt bulbs =240 watts)
If using fluorescent Bulbs, use the actuage wattage, not the incandescent equivalent
How many hours per day are the lights on?
Flat screens use less wattage than old-fashioned CRT types. Printers and/or sound systems will increase wattage.
How many hours per day is the computer used?
This section allows you to add power usage from 25 to 1500 watts for extra items or items not included above.
How many hours per day is the device used?

Based On Your Appliance Usage

Wattage Requirements Breakdown
Refrigerator watts = WattHours =
Television watts    = WattHours =
MicroWave watts = WattHours =
House lights watts = WattHours =
Computer system = WattHours =
Misc items watts  = WattHours =
Summary of WattHours required
Total daily WattHours required     =
WattHours required for 3 days     =
Battery capacity (50% discharge) =
Battery Bank size in AmpHours
12 Volt 24 Volt 48 Volt


TV Wattage Estimator:

Screen Area:

First, we need to estimate the screen size. When a TV is given as 52 inches, the 52 inches is measured diagonally across the screen, it is not the width of the screen. If you want to calculate the width, the classic trig formula is:
A² + B² = C²
where A is the width, B is the height, and C is the length of the the diagonal of the TV.

Since there are a million possibilities of combinations of A² + B², You also have to know the aspect ratio, which is either 16:9 (letterbox) or 4:3 (traditional)

Example: 52in TV (4:3) aspect ratio

52² = 2704 sq. inch
A = 4/3(B)
2704 = 1.33²B²
2704/1.76 = B²
B= 31.3 in
A = 41.5
Screen area = 31.3 * 41.5 = 1299.6 sq inches.


TV Watt values per square inch

Microdisplay rear projector: 0.14 watt per square inch
LCD: 0.29 watt per square inch
Plasma: 0.34 watt per square inch
CRT (non flat-panel): 0.34 watt per square inch