That 150w draw is the max draw. Unless you're using something that needs that much power it's not going to draw that at all times. Especially if what your planning on running is a pump like that with such a small draw.
Just be aware your not supposed to go above 20amp draw on the hybrid.Unrelated, but for hybrid models you can mount this right in the trunk to get 1200W (or more)
View attachment 422822
Again that's not recommended according to the factory of just about every hybrid car. I have seen people in the forums with 1200w-1500w stereo systems. Just because you did doesn't mean you should have. And correction it's 30amp 350wax recommended. I confused it because my sub amp is a 20amp draw.Venturing out into the Prius forums it looks like people are pulling about 50 amps so a 1000 watt inverter seems to be the max. With the car in "Ready" and not driving.