Help sizing my battery bank.

[maw1000]

I have a question about the sizing of my battery bank. I have a fish aquarium that I want to run off grid because of rolling power outages we might have in California. I was looking at using a MPP solar all in one inverter. I will be recharging the batteries with solar. I want to build a system that can run 24 hours and recharge itself in the winter time. I don’t need to go three days if there’s no sun. If I have to connect to the grid if the batteries get to low then the inverter will switch over automatically. In my location my peak sun hours in winter is average 3.42. I am planning on building the battery bank with lithium batteries. so I was wondering how many amp hours would I need to run my system in the winter time. I am giving you a break out how much wattage is my fish tank uses per hour. When I run the lights that’s when I use the most electricity and I run them between 2 PM and 10 PM every day. I figured daytime the solar would pretty much run the system and keep the batteries charged. Here is a break down by hour of usage.

 

[Bossrox]

You're using almost 1kw per day & since during the day you're using solar to do the job then you only need 125% higher in battery power than what your overnite use tallies up to. You can take most lithiums down to 90% or more but like lead acids, you're shrinking their life span so I would size your lith's so you keep the draw to an 80% average.

Then since you're only using a kw day, you don't need a whole bunch of panels. A single 300 watt panel is about all you need. On a good sunny 7 hr day you'll get about 1600 watts, enough to supply your load & fully charge the batts but an extra panel to cover less than ideal days would be a better build.