BRRRR - How much can you actually cash out at the Refi?

[Scott Graham]

Hi BP - I am in the process of closing on my first duplex and I want to use the BRRRR strategy on this property. The part of the BRRRR strategy that I do not fully grasp is how much can one truly cash out after refinancing a property? For example:

Purchase Price = $20K

Rehab/Construction Loan from Bank = $80K

After the rehab is complete and tenants are occupying the property - if I refinance the property through the bank for $150K - am I allowed to withdraw 75% of $150K loan or is it the difference between the original construction loan of $80K and refi loan of $150K? 

Thank you for your help,

Scott