I am back with another question about batteries. The batteries that the solar store recommended to me in their original quote for the backup system were the following:
12V/110AH/20HR deep cycle AGM-GEL combination made by Master Solar.
They recommended that I use two of these. I recognize the nomenclature: 12V = 12 volt battery; 110AH = 110 amp hours; 20HR = 20 hours?
If 20HR indeed is 20 hours, does this mean that the battery can run for a maximum of 20 hours at 110AH before it needs to be recharged?
If one battery is 110AH, does this mean that you can get 220AH if the two are connected?
I had originally asked for a quote from the solar outfit here to run my aquaponics system, powered by a 92 watt submersible AC water pump in continuous use (24 hours), completely with solar. But I had a major sticker shock when I saw the quote, which prompted me to go in the direction of a backup system charged off the grid electric system that I wrote about here in previous posts.
In the original quote, they said I need 4 of the batteries listed above connected to produce 24V to adequately run the 92-watt pump 24 hours continuously with 3 - 100-watt solar panels. I assumed at the time that I needed the 3 panels to keep the batteries adequately charged. However, now I am not so sure. The pump only uses 92-watts per hour. That is less than one 100-watt light bulb in continuous use.
However, my reason for writing is to understand amp hours. I found a website that guides you to determine your battery needs. Below are the calculations to run my pump.
Pump: 92 watts X 24 hours = 2208 watts
Independence: 3 days - 2208 X 3 = 6624 watts
Battery drain: 40% - 6624 ÷ 0.4 = 16,560 watts
Amps required: 16,560 ÷ 24V = 690AH
These calculations, if correct, indicate that I need 690AH? to run the pump continuously. However, the 4 batteries that they recommended are only 110AH each. Any way you slice it, I cannot get that battery configuration to add up to the 690AH that the calculations say that I will need.
Am I missing something? Originally, I had thought that the four batteries were overkill, but after doing the calculations above, it seems that they might be insufficient.