Solar Generator Comparison Calculator

solar system comparison calculator

This calculator will compare up to two solar generator systems by calculating how long you can run appliances WITHOUT SUN, as well as calculating recharge times, efficiency and more.

There are three steps to this calculator.

1- Choose up to two systems to compare.

2- Enter all appliances and tools you will be running in an emergency situation. Usually this means critical things, like a fridge or freezer, or maybe even a gas furnace.

3- Click the “Calculate!” button to calculate the results for the systems.

Step 1: Choose systems to compare.

System #1



System #2



Step 2: Choose what you will run.

Power Usage:
















  Step 3: Calculate the results.

Remember to recalculate after any changes!

  System #1

  System #2

              Solar Generator
Run Time = The amount of time in hours the system
will run without any sun. For critical loads such a
refrigerators, freezers, furnace, etc. This time should
be at least 48 hours to last through stormy weather.

Recharge Time = The time in hours to recharge your
batteries if fully drained to there maximum level of

System Efficiency = The average of several effiecinecy
measurements. Anything over 70 Is extremely good.
Anything under 50 is poor, and you should consider
a different system for your application.

Cost per hour runtime = The amount in dollars it will
cost you for each hour of Run Time you have.

System results are calculated from manufacturers reported

* Actual charge times will vary depending on outside temperature, type of batteries, and other variables. However this is a good approximation, and much more realistic than other charge times you will see, because it takes into account solar panel size, battery size,max DOD of battery bank, as well as the two phases of charging (Bulk, Absorption). Float charge time is not calculated in, because it can range from 0 to 12 hours depending on the type of battery. However after the absorption charge your batteries are nearly full.
In order to maintain long battery life you should allow for a good float time often, unless your battery bank is lithium, then you do not need to float charge your batteries.