electronics testing capacitors
ok, i can answer my own question after using LTspice and Mathway tools.

V0 = Voltage before test discharge resistor is in circuit

V1 = Voltage immediately when discharge resistor is in circuit

V2 = Voltage at end of discharge resistor in circuit

t = discharge time

R = discharge resistor

ESR = ?

C = ?

ESR = -1 * R + ((V0 * R) / V1)

C = -t / ( ln(V2/V1) * (R + ESR))

For example

R = 7

V0 = 50.1

V1 = 29.06

V2 = 12.03 

t = 0.005

ESR = 5

C = 470uf