How do private lenders work?

[Ezra Soto]

Need some advice. I am in the middle of a cash out refi on my investment property to invest in a duplex. The problem I'm having is that the banks want 25%  and that will take all my cash  and I would like to keep some cash for emergency funds. I think 20% down would be perfect. I think I seen some private lenders do 20% down. Need some guidance.