True solar build possible?

The panels are so light and thin that I duct taped them to the roof. with black gorilla tape they actually look very nice and match the car's dark blue coloring pretty closely. I have it trailing down the inside. I haven't had any issues with leaks

 

Alright guys here is the current status. I have started to narrow down the concept with a Prolong Battery Reconditioner/Charger. I am going to see if it's possible to run that while the car is on but I have to speak with the company some more.

Here is where it gets interesting. I found an isolating battery combiner that will allow 2 inputs to power one output and protect either side should the other give out. This would allow me to splice into the 12v output from the converter and supply half of the 12v load with solar and I will be trying the possibility of adding a dash switch to disconnect the converter input and run fully off solar until the battery gets too low and I switch back to both. My current plan is to confirm with my mechanic the best way to tap into the 12v output from the converter before it hits any of the car's systems or fuses to let all of that protect the system as normal. I saw on another post here that I might have to wire the system to be 24v and get a 24v to 13.8v step down converter to ensure solid 13.8v for the system but I am going to test it first to see if it can handle the batteries going lower like 12-13v range. One way or another I will start streamlining the system possibly swap the batteries for a couple 50ah Lifepo4 batteries in series for the 24v but that will be like $600. Most likely I will wind up with 2-4 55ah batteries wired for 24v and a step down converter. so far if I was going to do this from scratch I would go with 2 120w panels in series, a 10a mppt charge controller, 24v battery bank of capacity yet to be determined, voltage shut off switch, battery combiner, and a dash switch to enable/disable the prius converter connection. I might go with an 80a mppt controller to avoid having to buy a voltage switch but since the panel wattage is so small it would make sense to go with a cheaper mppt and a voltage switch. Honestly for $80 an 80 amp pwm controller that can do both might be a good cost saver but if I can get more charge out of the panels it would translate to longer discharge cycle from the offset of the panels charging while the batteries are being drained. I will find out today if this will work or if its back to the drawing board.

Also I live in a cooperative housing townhome. I can't put anything on the roof and have no space in my front yard and backyard is shaded. The only solar I have access to is that which hits my car

 

New update. The car doesn't like it when you interrupt the connection from the converter to the fuse box. Possibly the voltage is too low. The car actually seems to run just fine in park when all the fuse box is powered by the 12v batts with no input from the converter but that thing puts out 14.65 volts and I think the system expects that. That is why I wanted to do a step down converter that I found which is adjustable voltage and just have it put out 14.7 volts and use the battery combiner but all of this equipment is designed to work with a negative connection back to the batteries. If I can't do this my other option is to tap into individual systems via the fuse box but that could get messy.

The most interesting thing right now is that I think I can do this same idea with the inside fuse box which seems to control a ton of low level lighting and such. I opened it up and saw the same 6 gauge white wire just like the 12v battery-fusebox connection. If I can just unplug that I can avoid a bunch of hastle. Hopefully it likes that more. The plan is to do this tomorrow and see what happens.

 

Ok so I spent a good 4 or 5 hours on the road and the car had no problems running that second fusebox off batteries. The only issue is the thing pulls very little power. I have a very small subwoofer under the front seat and when I crank up the sound to the max I was pulling a total of 7 amps. That is 7 amps however that are NOT coming from the HV battery so that is a success. I think it powers all the little internal lights on the switches and the headlights, break lights, dome lights, power locks and windows. Lots of things that don't draw continuous power but do definitely drain it away over time. The next step is to start tapping into some of the hungrier systems in the front fuse box. Research indicates it has the headlights and brights, turn signals, random lights like the trunk light and lower inside door lights, and both the radio and it's amp all come out of there so if I can tap those I should be saving a decent amount of power. In truth I could tap in to most of the important things like brakes and power management but that stuff should probably just stay connected to the regular system. With my current 220Ah of 12v I can probably run most of the system at night for up to 5 or 6 hours. I'm buying some fuse taps which I will basically just jump from one output to the other and add a fuse to that connection. As I get an idea just how much power everything takes I can add more and more systems to the mix like the A/C cooling fan, the inverter cooling fan, and the radiator fan and see how stable everything looks.

Wish me luck!