Brinkman Rechargeable Battery Pack Run time



I'm looking for a portable solution to using a corded spotlight to avoid the short battery life related to rechargeable handhelds. I saw brinkman has a portable battery pack . It says it has 12amp/hour capacity. The lights I am looking to run range between 7.36 amps (200,000 cp) and 9 amps (400,000 cp). If I were to run the light constantly, how long would the power pack last if fully charged? I'm sure the answer is simple, just not familiar with this type of conversion.