Is it normal to have a dead 12V after 2 weeks of non-use?

yes, gen4 electronics seem to be putting a higher drain on the battery than previous gen's,

that being said, if it is the original battery, there have been a large number of defects

 

There have been a couple of similar threads recently - maybe check them out.

"...large number"? - I think it's just a few really. Most are fine. Mine is almost at 4 years old, and have had no problems.

 

Follow this thread. I am checking the 12v battery on PRIME (same 12v as Ge4) for a week without driving. I have never let my car sit longer than a few days before. But with the current lock-in situation, I am driving the car only once a week. I am still on 2nd day, but interpolating the data so far a fully charged battery 100% at 13.06v will have 50% or 12.01V in 1 week. So, yeah in 2 weeks, it can be low enough not to be able to start the car.

12v Battery Is Discharging, Re-Charge Now ! | Page 2 | PriusChat

 

right. when i say large number, i mean relative to past complaints. we've had a bunch here, not seen in past generations. still unknown whether it is the batteries or defective systems.

 

(EDIT) Wait a sec. I was just reminded in another thread that the Gen 4 vehicles use a conventional wet cell battery mounted in the engine bay. If that is correct......have you checked the "water" level in the battery lately ? That is critical for proper battery operation and health.

(original response)
NO. It's mostly a life style issue.
IF....your normal usage included a lot of short trips OR a lot of down time, then your 12 V battery likely was "low" when you parked it and that is hard on them.
If you have access to AC power where it is parked, a small battery tender is HIGHLY recommended.
If not, a half hour drive every 2 weeks should be enough to keep it going........IF it is fully charged to begin with.

 

Yes. Same thing.
Just because the CAR is 6 months old really says nothing about the age of the battery.
They can be 6 months to a year OLDER than the manufacture date of the car......which can be up to a year before it is sold.
And sitting around unused is WAY harder on wet cell batteries than the previous AGMs.

AND.....even perfectly healthy and fully charged, conventional wet cell batteries "self discharge" at a rate 5 to 10X as fast as an AGM.
Toyota did NOT go back to the old style batteries because they are in any way better..........except for the cost.

 

there's a thread by @Rob43 regarding prime 12volts. it might be worth your perusal

 

As others have mentioned, I've got a thread on this you should look into. Hopefully you leave your new battery alone as it should be charged and in great condition, then just monitor it daily for the 2 weeks that you mentioned. Try to follow the outlined testing procedure below and log your results, then please post up any findings of your lower voltage in my linked thread.

12v Battery Is Discharging, Re-Charge Now ! | PriusChat

Testing Procedure:

For those of you that would like to add your own testing results to this thread, here's what you need to do:

1) Fully charge your 12v battery using some type of external 12v battery charger.
2) Leave your car locked, BUT unlatch your hood so that you can access your 12v battery later without waking up the Primes computer. (Keep your key fob away)
3) Once each day after your initial full charge, check and measure your 12v battery voltage with a voltmeter and log your results.
4) Assuming you have other cars to drive, test for as many days as you conveniently can, the longer the better. For battery safety reasons, terminate your testing at roughly ~11.9 volts which is about ~40% for a 12v battery.
5) Re-Charge your 12v battery with your external 12v battery charger and bring it back up to a full charge.
6) Your testing is done, please post up your daily logged testing info.


Rob43

 

The trim level number that follows the Prius name has NOTHING to do with the design generation number.....which isn't obvious to a casual observer.

 

i suspect so, but a couple things come to mind: prime charges the 12v along with the hybrid battery when plugged in, albeit a very small amount.
due to the electronics, prime may have more quiescent draw, but that's only a thought, don't know anything for sure.

 

Deja vu:

2018 Prius completely dead even after jumping. What now? | PriusChat

 

yup, you gotta navigate carefully