2006 Prius wont start, and no ticking noise

Now that I've jotted down some notes, there seems to be a discrepancy in Optima batteries:

tanglefoot gives: Optima DS46B24R
Interstate site: Optima SC46B24RD

Scary because google search on the "SC46B24RD" only pops with Interstate Batteries, no place else.

 

That is because Interstate is using their own part numbering system. Optima is doing the same thing. Their number is similar to the OEM number but it too is different.

Note the number of the Toyota battery pictured below for the Prius that is being sold today at the dealers.



Look at the upper right hand corner of the picture above. Notice the part # which reads S46B24R, also note that the amp/hr rating is 45. The Optima Yellow Top has a 38 rating.

 

Big thanks to everyone for their input. Followed this youtube as a guideline for changing out the battery:

But, as seems like the norm, nothing is ever as easy as it seems on the Prius. I'm gonna assume the previous owner had issues changing out the battery the last time because a lot of the nuts had signs of stripping. The bolt post that keeps the battery [bracket] secure, by the side of the car, had metal in the grooves. It probably took me 15 mins to wrestle that one bolt off. It seems like Toyota doesn't think anyone has regular sized hands to work on these cars.

Bottom line, I got it done save for the bolt that secures the vent to the side - that one met it's demise going down the rabbit hole, never to be seen again. Car is running again. Thanks again to everyone who responded.

 

I would assume the prior owner had crappy tools insufficient for the job. If necessary you may want to replace the especially worn hardware.

Yes, it is really easy to lose that bolt which is now rattling around under the 12V battery. A magnetic wand might help you to find it without having to remove the battery.

 

If you fish the screw out for the vent duct that you dropped, you can easily start that screw into the hole. Use some lithium grease and place the grease on the head of the screw. Use enough grease that the screw will stay inside a socket on a extension when you hold the setup level. Then simply slip the whole thing into the hole where the screw goes and snug up the screw. A good flash light or even better a drop light will help you to see the hole on the side of the Prius. The part it screws into is plastic, so just snug up the screw.

If you can't use grease, put some tape on the head of the screw. Just enough to make the screw fit the socket as described above. I found the grease worked best for me. Tape was cumbersome to get just right, but grease worked real well.