Can you actually use a smaller font? Man.......

1st. Using an exhaust fan when the light is off; Is a waste of electricity.

If you can run a 1000w lamp, in you r grow space, and keep temps in the 70's, then you don't need much exhaust. However; it does help to recirculate air. You need athermostat that turns on fan if temps get above 80-85 degrees.

A 100-w lamp and ballast use approx. 11 amps. so you should not an issue runnign all you need for the small area you are using. doesn;t make sense that you are having issues in that regard.

lastly. Grow room should be 1/3 of total available size of entire grow area. this is because when you flower planys will be at least 2-3 times as big as vegged planys. One final note. You want the veg area hotter than the flower area; Always.