I've been traveling the country in my Prius for the past several months and so I thought I would share it here. I watched all the Prius camper videos on YouTube and asked tons of questions in the Prius camping groups on Facebook and got all the ideas I could and then finally made my own Prius camper. I installed a power inverter, fridge, microwave, sleeping platform, and a lot more stuff. Here it is: Posted via the PriusChat mobile app.
Nice setup! I would suggest moving the + connection for the inverter from the bolt where you have attached it, just to the nearby bolt that is on the other side of the battery fuse. (It's behind a little spot where the plastic of that fuse/connector housing folds out.) Here's what that looked like in my old Gen 1 (where the same style fuse/connector housing was used). The cover flap is folded open in the photo so you can see the connection. Connecting at that recommended spot means you've got the battery fuse between your inverter wiring and the battery, and also, at the far forward end under the hood, the DC/DC converter fuse between your wiring and the car's converter. That makes it a well-protected spot. It also means that when you are running the inverter and the car is READY (which I hope is pretty much always, right?), because your inverter's power is coming from the DC/DC converter then and not from the battery, you just have the voltage drop of one fuse on that power path, rather than two.
I cannot for the life of me figure out how to get the black plastic cover off of the positive terminal assembly on my Gen 2 to get at the bolt that you're referring to underneath. Does anyone know how to get at it without destroying it? Right now I have my inverter connected directly to the positive terminal (I just removed the red cover). That's how I've seen it done everywhere else, but if there is a better way, I'd definitely switch to it!
On my Gen 1 (I bet Gen 2's is pretty similar), on the side of that black plastic body was a flap that is just clipped closed over that bolt. It's 'hinged' at one side (the way they do 'hinged' for little plastic flaps, just very thin plastic where it folds over) and there's a little squeeze-to-release deal at the far edge. There wasn't any big neon sticker on it saying "OPEN HERE", but just looking at it for a minute or two thinking "there was surely a way they accessed the bolt for assembly..." did the trick for me.
Would a Prime be a better option for heating instead of turning the engine on at interval to warm up the cabin?
I took your idea and ran with it, making my own 2010 Toyota Prius IV build-out. Instead of batteries and inverters, I bought a Goal Zero that charges by the car when driving or solar panel which operated a fan and microwave. I'm selling my Prius and the buyer doesn't want the camper build-out. The build-out is available for sale: includes custom PVC frame and custom shaped platform. It is very lightweight yet sturdy, allows for all of the space the rear seats took up. Only asking $100 to cover costs of material.
