2023 Prius Prime + NOCO Genius 5: Under-hood charging vs. direct battery charging?

I recently picked up a NOCO Genius 5 to help maintain the 12V battery. My driving consists of a lot of short trips, and my 1-year-old OEM replacement battery (under warranty) recently tested in the yellow/"Recharge" range at Toyota, so I figured a maintainer would be good preventative maintenance.

I'm trying to determine the best charging method.

Option 1 - Under-hood charging posts
The Prime has the dedicated under-hood charging/jump points (positive terminal in the fuse box and negative chassis ground).

My concern is that when the hood is open, the MID constantly displays a "Hood Open" warning. Even if I clear the message, it comes back after a few seconds and the display stays illuminated. I'm assuming this keeps at least some of the vehicle electronics awake and draws power from the 12V battery while it's charging.

I considered routing the charger cable through the gap near the brake fluid reservoir and closing the hood, but I don't really like the idea of closing the hood over the charger clamps.

Option 2 - Direct battery connection
The 12V battery is in the rear cargo area.

My thought is to:

• Fold the rear seats down for access.
• Connect the NOCO directly to the battery (or install the permanent eyelet harness).
• Route the charger cable through the rear passenger window.
• Close the hatch and all doors.
• Leave only the rear passenger window open for the cable.

This way the car would think everything is closed:

• No hood-open warning.
• No hatch-open warning.
• Vehicle should be able to go into its normal sleep mode while the battery is charging.

The car is parked inside my garage, so leaving one rear window open overnight isn't a security concern.

Questions:

1. Is there any downside to charging this way?
2. Does the car actually stay awake with the hood open, or do the ECUs eventually go to sleep despite the warning message?
3. For those using a NOCO or similar maintainer on a Gen 5 Prius/Prime, which charging method have you found works best?

Thanks! I'm probably overthinking this, but since I plan to keep the car 10–15+ years, I'm trying to establish the best long-term charging routine.

 

Thanks for the reply Mendel. To answer your question, yes, I get a hood open message in the dash (the screen above the steering wheel - MID) even when the car is completely off. Power is off, key is not in any proximity of the car.

I can also confirm that notifications also show up on the MID whenever the rear trunk or any of the doors are open. Pushing the "back" arrow on the steering wheel (as shown on the MID notification) temporarily turns off the screen and message, but within a few seconds, the MID turns back on with the notifications. When multiple doors are open, the MID cycles through all of the open doors.

 

Oh perfect! Thanks for pointing that out.