2023 Hybrid 12 volt ROB says it is being driven in B , it is not.

i believe it does charge the battery in b mode.

it is possible some thing is draining the battery when off, or it is not charging properly when on, but most of the 12v issues are from not driving the car frequently enough.

did the dealer test the battery?

what is an rob btw?

 

Who told you that?

 

This doesn't have to do with your problem, but why do you think it's impossible to use B at 70 on the highway?

 

So you previously had a Gen 3 Prius, probably never worried about the 12V, and never had an issue with it. But Gen 5 has added a lot of new tech that puts additional demand on the 12V, perhaps even when the car is off. I'm not an expert on Gen 5, but it may be trying to connect to a Toyota cloud for over-the-air updates (OTAs) when the car is off. Perhaps try and turn off any connected services in the settings. In other makes, if the 12V gets low, it automatically puts the systems in low power mode essentially shutting down the connected services so as not to drain the battery completely.

I understand the 12V is in the back of the car again, but there are "jump" points under the hood. So, you could always connect a trickle charger to the "jump" points while the car is parked to keep the 12V topped up.

Maybe you've got a simple voltmeter and can connect it to these same jump points and read the voltage with the car off (should be around 12+ volts) and again with the car on (READY). It should be 14+ volts when the car is in READY showing the 12V is charging.

 

^ The key to resolving this is likely in the above.

Can you describe your usage of the car:

How many drives per week?
Roughly what distance?
Do you sometimes just sit parked, say listening to radio, and if so do you always have the car in “Ready” mode (fully on)?
Ever left a door ajar, for protracted period?
Ditto for light on?
Any accessories always plugged in (say dash cam, alarm system)?

If you’re open to a relatively easy DIY and have (or are ok to acquire) a digital multimeter, you can check:

battery voltage (a rough measure of battery status)

amperage draw on the battery when the car is off

For a more in-depth measure of battery status, most automotive retailers will have electronic load tester, and likely be willing to test your battery for free. It’s good for their business to do so; you may buy a replacement battery from them.

You can acquire DIY level tester similar to what the stores (and dealerships) use, for under $100 USD. One brand, that’s worked ok for me, is “Solar”. Current iteration is Solar BA9 I believe.

 

Strange things sometimes happen, and a new ( 2 week old ) battery dying, is strange, for whatever the reason is.
I recommend if there is another dealer within driving range, you could take it there and ask what they think the problem might be, keeping your fingers crossed that they can find and fix it.

 

12 volt battery has always been a prius issue. it has gotten worse with each new generation, and everyone has problems based on their driving habits.
if you drive every day, it will not raise its ugly head, but as it becomes less and less, the problem can surface.
that being said, someone has to determine if the battery is good, if the car is draining it excessively when off, or if the charging system isn't working properly.
once those things are eliminated, you should start keeping a battery maintainer on it.
i hope the engineers get you sorted!

 

• Do you have a white label on your driver door jam saying you have Spireon Lojack or some other gps tracker? Dealers now are loading these on all the cars they get for the extra profit. I have the label on my 2020 Prime and have 12 volt battery drain issues. It always starts but the battery runs down too fast for my driving time to recharge it.
• May want to ask dealer if you have lojack device to know.

 

Both of these claims were already questioned in earlier posts above. I'm just going to do it again, because I am doubtful of both of them, and I wouldn't want other readers of the thread to pick them up and start repeating them.

 

Any chance the keys are being stored near the car when you aren't driving?

The smart key system involves a certain amount of radio communication between the key and the car, typically as you are walking up to it. That radio conversation requires electrical power. The car initially uses a tiny amount of electrical power to sense whether the key is nearby.

When the key is thought to be approaching, a few extra circuits wake up in the car, and draw more electricity so that it can react immediately when you go to open the door.

If the keys never go that far away from the car, the car will waste a lot of 12v power in that "is he or isn't he?" stage of monitoring.

 

I drive in B mode all the time and have never had an issue with the 12v battery running low. An installed lojack would certainly drain the battery over time. Even without a lojack installed, the battery will eventually drain down if the car is not driven very often or for very short trips only. I see you only drive it 60-70 miles per week. Parked 12v battery drain is no doubt a bigger issue in the 2023 model vs 2010 model. My Prime manual states: ■If the vehicle is not used for a long time ●The 12-volt battery may discharge. In this event, charge the 12-volt battery.

 

Our '10 pretty much LIVES on a charger. Tough to do if you're street parked though...

 

Well, then I think bisco called it in post #2. Car needs more use overall, and more frequent use. And if that doesn't work, add a trickle charger.

Very generally speaking, a Prius is built to absorb lots of miles fast, and it is very good at that.

It's a bit less good at lasting a long time with little usage, but hopefully you'll get it worked out.