My LLC and solo-401K contirbution limit

Hello,

I have a consultation LLC and I work full time. The earnings from LLC I am saving it in solo-401K-roth and I have 401K with my full-time employment as well. How much money I could save in solo-401K per year?

 

Further, my wife does administrative works for the LLC and I pay her for those. Could she save some percentage of that in to her solo-401K acct.? if she had one?