Can't get power plug all the way in

Your 12v battery is most likely nearly dead. Put a charger on the 12v battery.
Charging the traction battery does not charge the 12v.
My guess is the car hasn’t been driven much.
There are many discussion on 12v battery discharge issues.
Not sure if not being able to insert the plug all the way in is related. Perhaps the locking pin is dependent on the 12v battery?

 

If the connector lock pin was in the lock position, which can happen when the doors are locked depending on your settings, and the 12V battery is too weak, it won't retract and you won't be able to plug in the EVSE cable. Which doesn't matter anyway because of the facts pointed out by @schja01 about not being able to charge the 12V in the way you wanted to anyway. As he said, put the 12V on a charger and all should be well again.

 

Starting the car briefly doesn't fix a dead 12V. It was still too dead to power everything needed for hybrid battery charging.

Now that you got it charging the hybrid battery, it's trickle charging the 12V while it charges the hybrid battery. But that still won't be nearly enough. You need to get that 12V charged back up for reliable operation. Then take it to an auto parts store to have it tested to see if it is damaged from being run so low.

 

You need to purchase a battery charger for your 12v battery to get it back to normal voltage. Going forward, you should buy an inexpensive battery maintainer trickle charger to keep it topped up.

 

Here is information on the 12v battery. Most likely, you will be needing to replace it with a new 12v battery. OEM battery may be in back-order in your area, but any 12v battery with a size group of either LN 1, H4, or 140R will work.
HELP - 12v battery on backorder | PriusChat

 

A smart battery maintainer is a very low amp charger that charges at a floating rate at ~1A or less. Its use is limited to maintaining an already charged 12v battery, but not really suited to charge a drained battery. It is a better investment to buy a smart charger that can charge at 5A (which is the max recommended amp for the 12v battery in the PP according to the manual). The higher the charge amp, the more expensive it will get. CTEK, NOCO, Schumacher, Battery Tender are all well-known brands. And there are tons of cheaper no-brand chargers out there. I used a cheap ~$20 5A smart charger (no longer available at Amazon) and worked fine. Since then, I invested in a better charger and now use the Victron Bluetooth charger. It is a bit pricy but about the came as CTEK or NOCO with similar specs, but one thing this one makes so useful is that it has Bluetooth communication built-in. During charging or maintenaning, you can check the battery status from your phone app.

 

You are welcome. One thing about the app for the Victron Bluetooth charger is that it can be used for a variety of Victron line-ups of battery charger, regulator, inverter, etc. The Victron is well known solar equipment manufacturer. I don't have a solar panel at our house, but I plan to install it sometime in the future. I may have more devices to be able to monitor then. Oh and another thing to remember is that it is connected by Bluetooth (not sure which ver.), and the range is maybe ~20ft max without walls. So, if your garage is detached or further away from where you are, it may not catch the signal.

Here are some screenshots of the Victron app with one of my 12v batteries currently in a "storage" mode.

 

This is not a phone. The AC charger for the traction battery does not charge the 12-V battery. You can only charge the 12-V battery from the traction battery if the car is in the READY mode.

 

I wouldn't get an aftermarket battery unless a Toyota battery is not available. It voids electrical warranties and can cause problems. Here is the Toyota battery:

2021 Toyota Prius Prime vehicle battery—00544H4052470—genuine Toyota part

Moreover, the reason the 12-V battery is dying seems to be either because the owner only does short trips or leaves the AC charger connected, the latter of which could quickly drain the 12-V battery. Playing the radio or keeping the lights on with the hybrid system off can also quickly drain the battery.

 

"I wouldn't get an aftermarket battery unless a Toyota battery is not available. It voids electrical warranties and can cause problems."
Is this true? What is different about any flooded lead acid 12v battery of the correct size and capacity? Can an AGM battery cause problems, or just give longer life? Like the ACDelco LN1 AGM battery from Summit Racing for $153 delivered.

Leaving the charge cable plugged in for even a couple of days has not discharged my 2017 battery significantly. Nor has running the radio for nearly an hour with the system off. Never a problem...so far.

 

I never heard or read such a claim by Toyota. Do you have any info on this? I really doubt your claim on voiding the electrical warranty and causing problems if aftermarket of the same size is used.

I have never replaced the 12v battery on my PP or previous Gen3, but for our Toyota Sienna, the battery was replaced at the Toyota dealer where I purchased the car. Yeah, it was long after the 3/36 warranty period, but our Toyota dealer didn't even use Genuine Toyota battery for the replacement battery.

 

It says:

Why Your Battery Should be a Genuine Toyota Replacement:

• The only warranty replacement battery approved for your Toyota vehicle.

2021 Toyota Prius Prime vehicle battery—00544H4052470—genuine Toyota part

By the way, from my experience, Toyota TrueStart batteries are of high quality—better than the Japanese Toyota batteries.

I would go for Toyota TrueStart over the ACDelco AGM, but those who used the latter can post their experiences.

 

I think you are mistaking the warranty on the battery. It says nothing about voiding the warranty on the vehicle.