Newbie with a problem

Prius never does well sitting especially in that part of the country in the winter a month really wow I guess y'all have better vehicles for that area to drive obviously the first thing to check is the 12 volt batteries capacity most O'Reilly's AutoZone's Menards and what have you can do this I doubt anyone's going to pass this battery but we'll see there's a bunch of fusible links fuses one at the battery a little one refuses up front all those need to be checked maybe take the battery out of the system remove the cables get a new one if that's what Menards or AutoZone tells you that's where you start if there are any lights on we need to have a capable scanner to get the codes It is necessary.

 

It's either the battery is past its use-by date or you've got loose connections to the battery. Either way, if you had attended to the problem 9 months ago you'd be golden. A stitch in time and all that.

There are some good threads here that detail the steps needed to see what needs to be replaced after a cross-connected jump start. Use the 'Advanced Search' feature (by clicking on the 'More...' button in the search box at the top of any forum page. You can then limit your search to only Gen 2 (and child) forums so you get information relevant to Gen 2s.

The fusible link is not the only fuse that needs checking.

 

Sounds to me like the 12v battery has a loose connection or is in a perpetual low state of charge and never really has the "charge time" to get to a healthy state. If you don't find a loose connection, at least get the battery tested. If it's marginal, it's probably best to get a new one.

As for the reverse jump, it's very likely the main fusible link is blown in the underhood fuse box, plus 2 or three of the normal circuit fuses.
Look through the clear plastic cover to inspect the upper right corner link. That's the one that normally melts for a reverse jump. There're several threads about replacing that fusible link, and even how to get around it temporarily while waiting for repairs. It can be a pain in the *** to replace but it's DIY do-able. I have about 15 of them on the shelf in the garage.

 

Checking fuses after a reverse jump, don't forget to check the small 5 amp one in the fuse block attached to the + 12 volt battery post. That can be blown, and will cause a DC/DC converter code if it is. Even a dealer can sometimes be fooled by that and say you need an inverter replacement in addition to the fuses.

I hear sometimes the converter really does go south. But be sure to check that fuse before giving up on it.