u/Dr--DisRespecT

I have a 5kW power solar plant with an average generation of 600 units per month (go upto 780 in peak summers), but with no batteries. I don't know anything about batteries. I want to install batteries now, my usage for the night is 4 fans max with 1 or 2 ACs rarely, not always. I have heard about lithium ion batteries. Can someone guide me about the batteries so I hope I don't waste my money