Step 1: Choose systems to compare.
 

System #1   Choose a System - Choose system #1 - - Titan 500 - - Titan 1000 - - Titan 1500 - - Titan 2000 - - Titan 2000 With two extra batteries - - Yeti 1250- - Yeti 1400 Lithium- - Yeti 3000 Lithium- -Apex with 500 watts solar- -Go Mini Solar Kit - -Patriot 1500- -Solar Max 5300 - -Solar Max 6000 - -Solgen 2500 - -Solgen 6000 - - Enter your own details -   System Specifications:   Invertery type - Pure sine wave - - Modified sine wave -   Inverter Idle power consumption in watts?   Inverter efficiency? %   Charge controller type? - High quality MPPT - - Non MPPT charge controller -   Batteries Maximum Depth of Discharge (DOD) %   Battery type - True Deep Cycle AGM - - Typical Deep Cycle AGM - - Marine Battery - - Lithium -   Batteries size in watt-hours   Solar size in watts   Retail cost

 
V.S.
 

System #2   Choose a System - Choose system #2 - - Titan 500 - - Titan 1000 - - Titan 1500 - - Titan 2000 - - Titan 2000 With two extra batteries - - Yeti 1250- - Yeti 1400 Lithium- - Yeti 3000 Lithium- -Apex with 500 watts solar- -Go Mini Solar Kit - -Patriot 1500- -Solar Max 5300 - -Solar Max 6000 - -Solgen 2500 - -Solgen 6000 - - Enter your own details -   System Specifications:   Invertery type - Pure sine wave - - Modified sine wave -   Inverter Idle power consumption in watts?   Inverter efficiency? %   Charge controller type? - High quality MPPT - - Non MPPT charge controller -   Batteries Maximum Depth of Discharge (DOD) %   Battery type - True Deep Cycle AGM - - Typical Deep Cycle AGM - - Marine Battery - - Lithium -   Batteries size in watt-hours   Solar size in watts   Retail cost

 

 
Step 2: Choose what you will run.
 

Power Usage:   Will you use a refrigerator? - 0 - - 1 - - 2 -   Will you use a freezer - 0 - - 1 - - 2 -   Number of hours/day lights will be on   How many watts of light   Dishwasher loads per day - 0 - - 1 - - 2 - - 3 - - 4 -   Washing maching loads per day - 0 - - 1 - - 2 - - 3 - - 4 -   Hot water gallons per day - 0 - - 10 gal - - 20 gal - - 30 gal - - 40 gal -   well pump gallons per day - 0 - - 100 gal - - 200 gal - - 300 gal - - 400 gal -   Will you run a gas furnace? - No - - Yes -   Computer: hours per day   Oven: hours per day   Cooktop burner: hours per day   Crock pot: meals per day   Microwave: hours per day   Other: Watt hours per day

Step 3: Calculate the results.   Remember to recalculate after any changes!
System #1   Run Time     Recharge Time     System Efficiency     Cost per hour runtime $		System #2   Run Time     Recharge Time     System Efficiency     Cost per hour runtime $
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 discharge. 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 information.

 
* 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.