Jump Starting The Car

prius doesn't need a lot of amperage, but i think the 12v outlet (aka cigarette lighter) is off with the car off

 

Okay, there's a couple different levels here.

First, the Prius doesn't use the 12V battery to start the engine. The 12V battery is only used to power up the electronics. Because of that, you need very little power to get the car going if you do manage to drain the 12V. In that sense, the toy you have might actually be strong enough to power up the car to get the electronics going after a short wait, and that could allow the car to use the main battery to start the engine.

But that leads us to problem number one. There's a reasonable chance the power needs to already be on in order for the power outlet to be active. But you can't power on the car until you've got a little juice in the battery. But to get a little juice into the battery, you need the power outlet to be active. You're stuck in a loop.

The second big problem is that those cigarette lighter starters are basically just useless toys. Did you ever actually try to use it? The far, far, far better solution is to just get a small jump pack and learn where the jump points are under the hood. The positive should be in the engine relay box under a red plastic protector; the negative just needs to go to a ground. You can get just about the smallest jump pack out there since the car needs so little juice to power up the electronics enough to use the main battery to start the engine.

Just a note: Keep the jump pack in the glove compartment or the center console. It seems logical to put it in one of those storage compartments under the cargo floor, but how are you going to open the rear hatch if the 12V battery is dead? It's not fun.

 

Sorry, I've never looked into it to that level.

I'm guessing the following would work, but that's only a guess. Someone with better experience can say what the better brands are.
NOCO - 500A Lithium Jump Starter - GB20

Or even: https://halo.acgbrands.com/en_US/bolt-flashlight.html

 

That has been true of a lot of cars for a long time, before Prius. There were too many plug-in devices in common use capable of draining the battery, to safely leave these outlets powered.

 

sounds like one of those things they used to sell on tv 50 years ago, around Christmastime