diy solar

diy solar
Resource icon

Battery and Solar Planning Tool Based on Representative Weather Data B70.0 Revised

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 .......
  • 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)
Results include ......
  • 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)
The Process ............
  • 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
Sample Output: Generator run events summary and solar data from PVWatts.
  • Sample Results.JPG
    Sample Results.JPG
    36.7 KB · Views: 158
  • Hurricane WH Plot.JPG
    Hurricane WH Plot.JPG
    37.1 KB · Views: 166
Author
hclarkx
Downloads
631
Views
1,976
First release
Last update
Rating
0.00 star(s) 0 ratings

Latest updates

  1. Updated to accept new PVWatts hourly solar download format.

    NREL recently changed the file format of the hourly solar data that they provide for your choice...
  2. THIS TOOL IS CURRENTLY NOT USABLE - PLEASE DO NOT DOWNLOAD UNTIL IT IS FIXED

    The National Renewable Energy Laboratory in Denver that makes PVWatts available has changed the...
  3. Small refinements, non user cells are protected.

    See title
Back
Top