If I Connect Solar Panels, A Battery, And A Load, Can I Figure Out How Long It Lasts?
Say the battery is 40 Amp-hours and the load uses 5A. If the solar panels are recharging the battery at 2A, do I have enough info to find out how long the batter will last? If not, what more would I need?
It depends on the application
You will draw 5 Amps for how many hours per day?
You will get 2 amps for how many hours per day?
For each hour of operation at 5A you will need (5/2) = 2.5 hours of sun.
Hope this properly answers your question
Assuming all voltages are the same, you’d be draining the battery at 5 -2 = 3 A.
Assuming the battery starts off fully charged, 40 Ah / 3A = 13 hours and 20 minutes, approx.
Of course, the discharge curve won’t be so discrete, but for a first approximation, this will work.