Hybrid Battery Cells replaced and car runs but can't start itself.

This post will be long winded as I want to make sure I don't miss any details that might help with this issue.

I drove my Prius from CA to TX a few years ago, after having the hybrid battery replaced by a company when I was still in CA (they used a refurbished battery). After a few months in TX It started sending codes that the hybrid battery was dying again so this time I took it upon myself to replace the cells that were mentioned in the codes. I took a very long time to get to replacing those cells, probably a year of very light use (just driving to the gas station once every 4-5 days to keep the 12v charged). I went on a flight back to CA for my sisters wedding and when I came back to TX I really slacked off on keeping up with the car and it just sat in the driveway for about 2 months. When I got back around to using it again, I jumped it and didn't even make it down the street before the car just died while in motion as soon as it let the engine turned off, I had to push it back into my driveway. After reading some forum posts it was clear it was the 12v, I went and bought a new one and sure enough with the new 12v in it would at least start itself (still had issues with the hybrid battery).

A few months later got around to taking out the hybrid battery and replacing the cells.
I took apart the hybrid battery found the cell that was reading lower voltage and replaced it with ones I bought off ebay. All cells in the hybrid battery after being replaced were reading 7.4 - 7.6. I built it all back up and jumped it again, and it worked like a charm. No more error codes, no lights at all, the Hybrid battery appeared to be charging itself while driving like normal and the car was running as smooth as its ever run since my trip out here to Tx. I took about a 30 min drive to try and give the car some time to charge the 12v, it would turn off the engine when I stopped at stoplights/signs and kick it back on when I was moving again, no problem. After my drive I get back to my house and park the car, I turned it off and immediately tried to turn it back on again to no avail. When I turned it off it still showed some lights, like the door open light but as soon as I tried to turn it on, it all went black. I jumped it again and it gave me an issue saying something along the lines of the transmission could not put the car into park and I needed to park it on a flat surface with the parking break fully engaged. It had given me the issue once before, before I replaced the cells in the hybrid battery and I just flicked it on and off a few times and it went away. I did so again while it was connected to the other car, on and off again a few times and the Prius turned back on again, however it now has the large red triangle with the ! in it light on. It is not sending any error codes it just has that light on. I imagine if I attempt to turn the Prius off again it will need to be jumped to start again (its still on and running outside, nothing connected to it, all on its own power). I checked the 12v with my voltage reader and it was at 13.8 so I don't think its the 12v, and like I said earlier I just replaced this 12v a few months ago.

I am not a smart man, at most I am a primate that knows how to use powertools, I have gotten this far from sheer dumb luck, brute force, and the help/guidance of kind people on the internet like yourselves. Any advice on what it could be or what I can check for next would be greatly appreciated. Thank you for taking the time to read this and any advice you may give to this small monkey-brained man.

 

Small Update I went out and drove the car around the block for a bit, the car drove fine but after a few laps it threw a check engine light/code. I tried to connect my OBD2 reader and read it from my phone but my phone would not connect to the OBD2 through Bluetooth for some reason even restarting my phone a few times. I turned off the car and tried to turn it back on and the same thing happened, some lights when I turned it off, when I tried to turn it on, everything went dark. Don't know if this helps at all just more information at least.