I've assembled a spreadsheet to size my RV solar/battery system. I didn't find anything like it on the internet so did the DIY thing. I've been using it for six years, through three battery and solar upgrades. It is well tested.
Currently the spreadsheet is in Excel but has been checked in Google Sheets.
There is no charge. The spreadsheet is in the public domain. There is a lot of documentation included in the spreadsheet.
NOTE: There is an energy use calculation page in the spreadsheet, but this is not the purpose of the spreadsheet. The purpose is to size a battery and solar system to limit generator run events, particularly as affected by weather.
Overview .......
Data Required ......
Currently the spreadsheet is in Excel but has been checked in Google Sheets.
There is no charge. The spreadsheet is in the public domain. There is a lot of documentation included in the spreadsheet.
NOTE: There is an energy use calculation page in the spreadsheet, but this is not the purpose of the spreadsheet. The purpose is to size a battery and solar system to limit generator run events, particularly as affected by weather.
Overview .......
- Extensive documentation (yes, I have a writing problem)
- A day/night load calculation worksheet (you can enter your data directly)
- Paste-in of representative yearly hourly solar data from PVWatts for specific camping locations
- Simulation of day to day evening and morning battery SOC
- Supports two mini-split or heatpump A/C units and electric fridge
- Designed for LiFePo4 batteries (user can approximate AGM with some effort)
- Evening generator run events (solar and/or battery falls short)
- Daytime generator run events (solar and/or battery falls very short)
- Generator Ah use at each generator run event
- Evening battery SOC (sundown)
- Morning battery SOC
- Percent of available solar used each day
- (the above and some other variables are provided in charts)
Data Required ......
- Day and night miscellaneous load data by season (summer & winter)
- Refrigerator energy use at 70F (amps and duty cycle) (12V or Residential)
- Space heater amps and hours of use
- A/C 1 rated Watts plus hours of use (day, evening, night)
- A/C 2 rated Watts plus hours of use (day, evening, night)
- Minimum battery morning SOC in percent
- Hourly weather data from PVWatts for specific locations of your choice
- (next above is created in the NREL PVWatts solar planning tool)
- Enter data
- Enter trial battery and solar array sizes
- See annual generator run events
- Adjust battery and solar array sizes for tolerable generator run events
